Home » Public Forums » GMCnet » [GMCnet] BRAKES!!!
| [GMCnet] BRAKES!!! [message #204963] |
Wed, 17 April 2013 15:07  |
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fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
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Senior Member |
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My braking system is not working correctly.
When I got the coach beginning of February, all was well.
a couple-three weeks ago, however, I got the brake warning light,
accompanied by the pedal doing nothing for the first half of its
travel. I'm still able to bring the coach to a stop, but I have to
really push hard if it's going to be a quick one. for a while, every
other pedal push would get full braking, and the light would go back
out. then, it was every third, then every fourth.
Now, it's on much of the time. I can reliably shut the light off, and
get normal pedal feel, but only if the parking brake is engaged.
without the parking brake, it's once in awhile. Judging by
temperatures and sound, its the rear brakes that I've lost. the front
reservoir is about half full.
Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
occurred to me that I don't know what the correct fluid to use is,
aside from the old GM part number, 5464831.
Any advice? i've already looked over Gene's brakes pages, and aside
from the advice that I install a vacuum pump, and which master
cylinder is OEM equivalent, nothing there seems terribly useful to my
situation.
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #204965 is a reply to message #204963] |
Wed, 17 April 2013 15:22  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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The front resevoir being low indicates that it is the rear brakes that are
responsible for your fluid loss. You more than likely have at the least,
poorly adjusted rear drum brakes, and more than likely have leaky wheel
cylinders which accounts for the fluid loss. The correct fluid for the
coach is indeed DOT 3. If the coach has sat idle for a long time, and then
been placed into service, moisture which condenses in the brake fluid
system has rusted your wheel cylinders, and damaged the seal between the
cylinder walls and the fluid cups. The rear brakes need to be inspected to
determine the extent of the damage. If you do not posess the skills and/or
experience to safely hoist the coach and remove the drums, then, it looks
like time to consult an expert. No mystery in the drum brakes, but a
quality job will insure your personal safety and that of those around you
when you drive the coach. NOW is a good time to take care of this.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Wed, Apr 17, 2013 at 1:07 PM, Patrick Fitzmorris
<fitzmorrispr@gmail.com>wrote:
> My braking system is not working correctly.
>
> When I got the coach beginning of February, all was well.
>
> a couple-three weeks ago, however, I got the brake warning light,
> accompanied by the pedal doing nothing for the first half of its
> travel. I'm still able to bring the coach to a stop, but I have to
> really push hard if it's going to be a quick one. for a while, every
> other pedal push would get full braking, and the light would go back
> out. then, it was every third, then every fourth.
>
> Now, it's on much of the time. I can reliably shut the light off, and
> get normal pedal feel, but only if the parking brake is engaged.
> without the parking brake, it's once in awhile. Judging by
> temperatures and sound, its the rear brakes that I've lost. the front
> reservoir is about half full.
>
> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
> occurred to me that I don't know what the correct fluid to use is,
> aside from the old GM part number, 5464831.
>
> Any advice? i've already looked over Gene's brakes pages, and aside
> from the advice that I install a vacuum pump, and which master
> cylinder is OEM equivalent, nothing there seems terribly useful to my
> situation.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] BRAKES!!! [message #204967 is a reply to message #204965] |
Wed, 17 April 2013 15:28 |
|
fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
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Senior Member |
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okay. While I have the know-how to do the rear brakes myself, the
tools and space and time are somewhat lacking.
Maybe I'll take it to a shop, and have them grease the rear wheel
bearings at the same time.
I'm guessing the light going out when parking brake applied has
something to do with the wheel cylinders being extended by the cable's
action, perhaps moving the piston past a portion of the cylinder wall
that has scoring or rust damage, allowing the pressure to build?
On Wed, Apr 17, 2013 at 1:22 PM, James Hupy <jamesh1296@gmail.com> wrote:
> The front resevoir being low indicates that it is the rear brakes that are
> responsible for your fluid loss. You more than likely have at the least,
> poorly adjusted rear drum brakes, and more than likely have leaky wheel
> cylinders which accounts for the fluid loss. The correct fluid for the
> coach is indeed DOT 3. If the coach has sat idle for a long time, and then
> been placed into service, moisture which condenses in the brake fluid
> system has rusted your wheel cylinders, and damaged the seal between the
> cylinder walls and the fluid cups. The rear brakes need to be inspected to
> determine the extent of the damage. If you do not posess the skills and/or
> experience to safely hoist the coach and remove the drums, then, it looks
> like time to consult an expert. No mystery in the drum brakes, but a
> quality job will insure your personal safety and that of those around you
> when you drive the coach. NOW is a good time to take care of this.
> Jim Hupy
> Salem, OR
> 78 GMC Royale 403
>
>
> On Wed, Apr 17, 2013 at 1:07 PM, Patrick Fitzmorris
> <fitzmorrispr@gmail.com>wrote:
>
>> My braking system is not working correctly.
>>
>> When I got the coach beginning of February, all was well.
>>
>> a couple-three weeks ago, however, I got the brake warning light,
>> accompanied by the pedal doing nothing for the first half of its
>> travel. I'm still able to bring the coach to a stop, but I have to
>> really push hard if it's going to be a quick one. for a while, every
>> other pedal push would get full braking, and the light would go back
>> out. then, it was every third, then every fourth.
>>
>> Now, it's on much of the time. I can reliably shut the light off, and
>> get normal pedal feel, but only if the parking brake is engaged.
>> without the parking brake, it's once in awhile. Judging by
>> temperatures and sound, its the rear brakes that I've lost. the front
>> reservoir is about half full.
>>
>> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
>> occurred to me that I don't know what the correct fluid to use is,
>> aside from the old GM part number, 5464831.
>>
>> Any advice? i've already looked over Gene's brakes pages, and aside
>> from the advice that I install a vacuum pump, and which master
>> cylinder is OEM equivalent, nothing there seems terribly useful to my
>> situation.
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #204974 is a reply to message #204963] |
Wed, 17 April 2013 16:09 |
Jim Bounds
Messages: 842
Registered: January 2004
Karma: 0
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Senior Member |
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If pulling the E brake effects the issue, the overwhelming problem is in the rear drums-- out of adjustment, etc. The bigger issue though is this is a new mechanism to you, a 30+ year old box of mold covered chocolates and you are talking about your brakes-- probably the most important system on the coach. DO NOT patch the problem, take the brakes apart completely, replace all of it and at least the brakes will new be "restored" and you can have the peace of mind that if all else fails you can ride the horse to the ground and jump off! Consider these parts:
o Brake master cylinder (no rebuild, only new)
o combination valve (get a new one)
o Front brake hoses (the original rubber ones swell and close off from the inside)
o Rear brake hoses (if the shoulders where the bolt goes through the center manifold is rounded, they are original-- move away slowly!)
o Wheel cylinders (4) (how could they not be leaking if they have been just sitting around)
o Calipers (they are cheap, directly from a Toro)
o Pads (stock pads are less than $20 a set)
o Shoes (riveted 462 RR, they are small money
Gravity, pressure then pump bleed with DOT3 and you should have great brakes. If that works well, install a new sensatized booster and your brake problems will be a thing of the past and won;t you feel better knowing you can stop your 12,000 pound projectile?
All of this would be less money than throwing money on the wall changing things to discs bringing your personal liability to a crashindo
Yea, I know this will create contriversy, sorry -- just my opinion,
Jim Bounds
----------------------
________________________________
From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
To: gmclist <gmclist@temp.gmcnet.org>
Sent: Wednesday, April 17, 2013 4:07 PM
Subject: [GMCnet] BRAKES!!!
My braking system is not working correctly.
When I got the coach beginning of February, all was well.
a couple-three weeks ago, however, I got the brake warning light,
accompanied by the pedal doing nothing for the first half of its
travel. I'm still able to bring the coach to a stop, but I have to
really push hard if it's going to be a quick one. for a while, every
other pedal push would get full braking, and the light would go back
out. then, it was every third, then every fourth.
Now, it's on much of the time. I can reliably shut the light off, and
get normal pedal feel, but only if the parking brake is engaged.
without the parking brake, it's once in awhile. Judging by
temperatures and sound, its the rear brakes that I've lost. the front
reservoir is about half full.
Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
occurred to me that I don't know what the correct fluid to use is,
aside from the old GM part number, 5464831.
Any advice? i've already looked over Gene's brakes pages, and aside
from the advice that I install a vacuum pump, and which master
cylinder is OEM equivalent, nothing there seems terribly useful to my
situation.
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| Re: [GMCnet] BRAKES!!! [message #204980 is a reply to message #204974] |
Wed, 17 April 2013 16:55 |
|
fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
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Senior Member |
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well, no disagreement from my end of things. Disks may be nice, but
they're not necessary. ~90% of the city bus fleet still runs four
wheel drums. Granted, they're air brakes, and the drums are massive
(as are the pistons) but they aren't finned.
I still figure that if drums are good enough for a 15 ton 40 foot
stainless steel behemoth, they're plenty good for me.
When you say rear brake hoses, you mean the hoses that run from the
center of the bogie assembly to the wheels, right?
As for the sensitized booster, what sets it apart from the original
one, which has always seemed to work excellently for my purposes?
How do i do the gravity part of the bleeding? i'm familiar with the
concept of pressure bleeding, and pumping the brake pedal, but i've
never heard of or done a gravity bleed.
Where do I get a combination valve? is it a standard part that is not
unique to our coaches?
How about them wheel cylinders? if I have the parts counter guy look
up a toro, will he find the right ones? I don't know if they're leaky
or not. Is it possible that the same behavior could result from
another issue, like frozen adjusters? the PO claimed he drove it
regularly to keep it limber, but it did only have ~62k on the clock.
I've been able to come to a smooth stop with only front brakes, in no
small part because of the fact that as one who was trained how to
safely drive a 12-15 ton city bus, I always give myself plenty of
room. but my luck is bound to run out sooner rather than later, so i
want to fix this.
On Wed, Apr 17, 2013 at 2:09 PM, Jim Bounds <gmccoop@yahoo.com> wrote:
> If pulling the E brake effects the issue, the overwhelming problem is in the rear drums-- out of adjustment, etc. The bigger issue though is this is a new mechanism to you, a 30+ year old box of mold covered chocolates and you are talking about your brakes-- probably the most important system on the coach. DO NOT patch the problem, take the brakes apart completely, replace all of it and at least the brakes will new be "restored" and you can have the peace of mind that if all else fails you can ride the horse to the ground and jump off! Consider these parts:
>
> o Brake master cylinder (no rebuild, only new)
> o combination valve (get a new one)
> o Front brake hoses (the original rubber ones swell and close off from the inside)
> o Rear brake hoses (if the shoulders where the bolt goes through the center manifold is rounded, they are original-- move away slowly!)
> o Wheel cylinders (4) (how could they not be leaking if they have been just sitting around)
> o Calipers (they are cheap, directly from a Toro)
> o Pads (stock pads are less than $20 a set)
> o Shoes (riveted 462 RR, they are small money
>
> Gravity, pressure then pump bleed with DOT3 and you should have great brakes. If that works well, install a new sensatized booster and your brake problems will be a thing of the past and won;t you feel better knowing you can stop your 12,000 pound projectile?
>
> All of this would be less money than throwing money on the wall changing things to discs bringing your personal liability to a crashindo
> Yea, I know this will create contriversy, sorry -- just my opinion,
>
> Jim Bounds
> ----------------------
>
>
> ________________________________
> From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
> To: gmclist <gmclist@temp.gmcnet.org>
> Sent: Wednesday, April 17, 2013 4:07 PM
> Subject: [GMCnet] BRAKES!!!
>
>
> My braking system is not working correctly.
>
> When I got the coach beginning of February, all was well.
>
> a couple-three weeks ago, however, I got the brake warning light,
> accompanied by the pedal doing nothing for the first half of its
> travel. I'm still able to bring the coach to a stop, but I have to
> really push hard if it's going to be a quick one. for a while, every
> other pedal push would get full braking, and the light would go back
> out. then, it was every third, then every fourth.
>
> Now, it's on much of the time. I can reliably shut the light off, and
> get normal pedal feel, but only if the parking brake is engaged.
> without the parking brake, it's once in awhile. Judging by
> temperatures and sound, its the rear brakes that I've lost. the front
> reservoir is about half full.
>
> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
> occurred to me that I don't know what the correct fluid to use is,
> aside from the old GM part number, 5464831.
>
> Any advice? i've already looked over Gene's brakes pages, and aside
> from the advice that I install a vacuum pump, and which master
> cylinder is OEM equivalent, nothing there seems terribly useful to my
> situation.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #204985 is a reply to message #204963] |
Wed, 17 April 2013 17:31 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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| fitzmorrispr wrote on Wed, 17 April 2013 15:07 |
My braking system is not working correctly.
When I got the coach beginning of February, all was well.
a couple-three weeks ago, however, I got the brake warning light, accompanied by the pedal doing nothing for the first half of its travel.
|
Brake warning light means low of fluid. Brakes not doing anything for half a pedal reinforces that.| Quote: |
I'm still able to bring the coach to a stop, but I have to really push hard if it's going to be a quick one.
|
That's because you are only stopping on half (or less) of the wheels.| Quote: |
for a while, every other pedal push would get full braking, and the light would go back out. then, it was every third, then every fourth.
Now, it's on much of the time. I can reliably shut the light off, and get normal pedal feel, but only if the parking brake is engaged. without the parking brake, it's once in awhile. Judging by temperatures and sound, its the rear brakes that I've lost. the front reservoir is about half full.
|
Sounds like you have a leak and some air in the lines. Also, setting the parking brake is accomplishing the equivalent of adjusting the rear brakes.| Quote: |
Now I went and bought a bottle of DOT3 fluid at O'reilly, but it occurred to me that I don't know what the correct fluid to use is, aside from the old GM part number, 5464831.
|
DOT 3 is the correct stuff.| Quote: |
Any advice? i've already looked over Gene's brakes pages, and aside from the advice that I install a vacuum pump, and which master cylinder is OEM equivalent, nothing there seems terribly useful to my situation.
|
You might have a leak, or not. The rear wheel cylinders might not be retracting (due to rust and such). Jim is correct that the safest approach is new master cylinder, new combination valve, new wheel cylinders in the rear, new calipers in the front, new flex lines on all 6, new pads in front and new shoes in the rear. Adjust rears and bleed all wheel cylinders and calipers.
If you were a shadetree mechanic, you could find the specific problem area and fix only that, but then you would be messing with the brakes again in the not too distant future. Best to do it all at once, and do it right. Brakes aren't something to cut corners on.
Any brake shop could do the brake work, where they will have trouble is jacking it up without damaging something. If not for that, you could take it anywhere and get the work done. One of the subtle nuances of the GMC vs a passenger car is that the rear drums come off with the hub instead of separately. Might as well have the rear bearings greased while it is apart.
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| Re: [GMCnet] BRAKES!!! [message #204986 is a reply to message #204980] |
Wed, 17 April 2013 17:37 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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If you want to get your brakes back to OEM condition do exactly as Jim suggests. Jim is having you refurbish the entire brake system which is a good move. Most parts are available from your local auto parts store.
The combination valve is available from either Jim Bounds or Jim Kanomata. (GMC Coop or Applied GMC)
The sensitized booster is a booster that makes it easier to press on the brake pedal and again is available from either of the Jims.
If you need new rotors or drums, They are a big job and they are a unique part, again available from either of the Jims and other GMC specific suppliers.
If all you want to do is to get back to stock then follow Jim Bounds'suggestions.
I have a small additional suggestion.
Use Dot 4 or ATE brand fluid. It is fully compatible with DOT 3 but has a higher boiling point.
After the above things that Jim B. listed there are lots of "upgrades". I'm not going to list them as I'll miss a few and at this point I believe you are attempting to return yours to normal operation.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] BRAKES!!! [message #204994 is a reply to message #204980] |
Wed, 17 April 2013 18:28 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Patrick,
From the questions you've asked below I would suggest you do a bit of homework and download a copy of this manual:
http://www.bdub.net/manuals/X7525/index.html
Once you're read and studied the entire section on BRAKES ask us any questions to help you fully understand and comprehend what
you've read.
Regards,
Rob M.
-----Original Message-----
From: Patrick Fitzmorris
well, no disagreement from my end of things. Disks may be nice, but
they're not necessary. ~90% of the city bus fleet still runs four
wheel drums. Granted, they're air brakes, and the drums are massive
(as are the pistons) but they aren't finned.
I still figure that if drums are good enough for a 15 ton 40 foot
stainless steel behemoth, they're plenty good for me.
When you say rear brake hoses, you mean the hoses that run from the
center of the bogie assembly to the wheels, right?
As for the sensitized booster, what sets it apart from the original
one, which has always seemed to work excellently for my purposes?
How do i do the gravity part of the bleeding? i'm familiar with the
concept of pressure bleeding, and pumping the brake pedal, but i've
never heard of or done a gravity bleed.
Where do I get a combination valve? is it a standard part that is not
unique to our coaches?
How about them wheel cylinders? if I have the parts counter guy look
up a toro, will he find the right ones? I don't know if they're leaky
or not. Is it possible that the same behavior could result from
another issue, like frozen adjusters? the PO claimed he drove it
regularly to keep it limber, but it did only have ~62k on the clock.
I've been able to come to a smooth stop with only front brakes, in no
small part because of the fact that as one who was trained how to
safely drive a 12-15 ton city bus, I always give myself plenty of
room. but my luck is bound to run out sooner rather than later, so i
want to fix this.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] BRAKES!!! [message #205000 is a reply to message #204963] |
Wed, 17 April 2013 19:20 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
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|
Both of mine showed this symoptom. Bleeding the front brakes properly cured both... the reservoir (back one strangely) had emptied and air had gotten in the line. I now check the reservoir much more often.
--johnny
'76 23' transmode norris
'76 palm beach
From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
To: gmclist <gmclist@temp.gmcnet.org>
Sent: Wednesday, April 17, 2013 4:07 PM
Subject: [GMCnet] BRAKES!!!
My braking system is not working correctly.
When I got the coach beginning of February, all was well.
a couple-three weeks ago, however, I got the brake warning light,
accompanied by the pedal doing nothing for the first half of its
travel. I'm still able to bring the coach to a stop, but I have to
really push hard if it's going to be a quick one. for a while, every
other pedal push would get full braking, and the light would go back
out. then, it was every third, then every fourth.
Now, it's on much of the time. I can reliably shut the light off, and
get normal pedal feel, but only if the parking brake is engaged.
without the parking brake, it's once in awhile. Judging by
temperatures and sound, its the rear brakes that I've lost. the front
reservoir is about half full.
Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
occurred to me that I don't know what the correct fluid to use is,
aside from the old GM part number, 5464831.
Any advice? i've already looked over Gene's brakes pages, and aside
from the advice that I install a vacuum pump, and which master
cylinder is OEM equivalent, nothing there seems terribly useful to my
situation.
_______________________________________________
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] BRAKES!!! [message #205002 is a reply to message #205000] |
Wed, 17 April 2013 19:54 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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One more item that always seems to get overlooked is a spring kit for the
rear brakes. Jim K has them for $13.00 for two wheels.
Most likely they are 35+ years old and have lost their tension.
http://www.appliedgmc.com/prod.itml/icOid/595
On Wed, Apr 17, 2013 at 6:20 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
> Both of mine showed this symoptom. Bleeding the front brakes properly
> cured both... the reservoir (back one strangely) had emptied and air had
> gotten in the line. I now check the reservoir much more often.
>
> --johnny
> '76 23' transmode norris
> '76 palm beach
>
> From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
> To: gmclist <gmclist@temp.gmcnet.org>
> Sent: Wednesday, April 17, 2013 4:07 PM
> Subject: [GMCnet] BRAKES!!!
>
>
> My braking system is not working correctly.
>
> When I got the coach beginning of February, all was well.
>
> a couple-three weeks ago, however, I got the brake warning light,
> accompanied by the pedal doing nothing for the first half of its
> travel. I'm still able to bring the coach to a stop, but I have to
> really push hard if it's going to be a quick one. for a while, every
> other pedal push would get full braking, and the light would go back
> out. then, it was every third, then every fourth.
>
> Now, it's on much of the time. I can reliably shut the light off, and
> get normal pedal feel, but only if the parking brake is engaged.
> without the parking brake, it's once in awhile. Judging by
> temperatures and sound, its the rear brakes that I've lost. the front
> reservoir is about half full.
>
> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
> occurred to me that I don't know what the correct fluid to use is,
> aside from the old GM part number, 5464831.
>
> Any advice? i've already looked over Gene's brakes pages, and aside
> from the advice that I install a vacuum pump, and which master
> cylinder is OEM equivalent, nothing there seems terribly useful to my
> situation.
> _______________________________________________
> GMCnet mailing list
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--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] BRAKES!!! [message #205034 is a reply to message #205002] |
Thu, 18 April 2013 00:58 |
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fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
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Senior Member |
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Rob, i've skimmed that section a few times, since I've got the full
print manual. i'll be sure to read it thoroughly before proceeding.
Kelvin, if I find I need a drum or three, i'll be sure to give you a ring.
Johnny, i suppose bleeding the front might yet fix this, though for
sure they're the ones that work, and my rear reservoir is full
and I guess I'll take Ken's advice and use DOT4. Maybe that blue stuff...
Any gems you guys got in reserve would be appreciated :p
On Wed, Apr 17, 2013 at 5:54 PM, Bruce Hart <hartsgmc@gmail.com> wrote:
> One more item that always seems to get overlooked is a spring kit for the
> rear brakes. Jim K has them for $13.00 for two wheels.
> Most likely they are 35+ years old and have lost their tension.
> http://www.appliedgmc.com/prod.itml/icOid/595
>
> On Wed, Apr 17, 2013 at 6:20 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
>
>> Both of mine showed this symoptom. Bleeding the front brakes properly
>> cured both... the reservoir (back one strangely) had emptied and air had
>> gotten in the line. I now check the reservoir much more often.
>>
>> --johnny
>> '76 23' transmode norris
>> '76 palm beach
>>
>> From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
>> To: gmclist <gmclist@temp.gmcnet.org>
>> Sent: Wednesday, April 17, 2013 4:07 PM
>> Subject: [GMCnet] BRAKES!!!
>>
>>
>> My braking system is not working correctly.
>>
>> When I got the coach beginning of February, all was well.
>>
>> a couple-three weeks ago, however, I got the brake warning light,
>> accompanied by the pedal doing nothing for the first half of its
>> travel. I'm still able to bring the coach to a stop, but I have to
>> really push hard if it's going to be a quick one. for a while, every
>> other pedal push would get full braking, and the light would go back
>> out. then, it was every third, then every fourth.
>>
>> Now, it's on much of the time. I can reliably shut the light off, and
>> get normal pedal feel, but only if the parking brake is engaged.
>> without the parking brake, it's once in awhile. Judging by
>> temperatures and sound, its the rear brakes that I've lost. the front
>> reservoir is about half full.
>>
>> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
>> occurred to me that I don't know what the correct fluid to use is,
>> aside from the old GM part number, 5464831.
>>
>> Any advice? i've already looked over Gene's brakes pages, and aside
>> from the advice that I install a vacuum pump, and which master
>> cylinder is OEM equivalent, nothing there seems terribly useful to my
>> situation.
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
> _______________________________________________
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #205041 is a reply to message #205034] |
Thu, 18 April 2013 05:04 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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The symptom you describe really sounds like rear brakes. I blew a rear wheel cylinder coming out of a GMCMI rally in Louisiana a few years back and it acted the same way as yours.
The combination valve holds off the engagement of the front brakes until there is some pressure on the rears. With a leak back there or badly adjusted rear brakes you will get this type of failure.
In my case I put a plug on the failing line, filled it up with fluid, bleed the rears only, and drove home to Indiana (800 to 1000 miles) on three rear brakes.
After I got home, I replaced all 4 rear wheel cylinders and the rear hoses. I used 1 and 1/16" wheel cylinders on the middle wheels and 7/8" on the rear most wheels. The cylinders were very cheap. I got the hoses from Jim Bounds. I forget what they cost but they are unique to the GMC.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] BRAKES!!! [message #205047 is a reply to message #205034] |
Thu, 18 April 2013 06:38 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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If the reservoir hasn't gone empty, then air isn't the (primary) problem. Unfortunately. And as someone pointed out, once you dive into them, might's well to rebuild the system and be done with it. I picked up a set of cylinders from JimK for my project coach, it seems they were like right around a hundred counting mailing, and they're the proper sizes. For the rest, I'd decide, gonna keep it forever or flog it off directly? Keeper will get braided stainless flex hoses and stainless lines. Flogger will get new rubber hoses and PolyArmour lines. Either will work safely, the stainless stuff will last as long as the fiberglass and aluminum in the body.
This is the point at which you'd decide whether to put in one of the improved braking ststems or not. Which would lead to 'do I upgrade the front suspension or not?' Which leads to the Law Of Jester, "You can't ever do Just One Thing." Your pocket and ambition level wuill decide... but I'd rebuild the brakes anyhow at this point.
--johnny
'76 23' transmode norris
'76 palm beach
Down the street from Road Atlanta
________________________________
From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
To: gmclist <gmclist@temp.gmcnet.org>
Sent: Thursday, April 18, 2013 1:58 AM
Subject: Re: [GMCnet] BRAKES!!!
Rob, i've skimmed that section a few times, since I've got the full
print manual. i'll be sure to read it thoroughly before proceeding.
Kelvin, if I find I need a drum or three, i'll be sure to give you a ring.
Johnny, i suppose bleeding the front might yet fix this, though for
sure they're the ones that work, and my rear reservoir is full
and I guess I'll take Ken's advice and use DOT4. Maybe that blue stuff...
Any gems you guys got in reserve would be appreciated :p
_______________________________________________
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Unsubscribe or Change List Options:
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] BRAKES!!! [message #205049 is a reply to message #205002] |
Thu, 18 April 2013 06:53 |
Jim Bounds
Messages: 842
Registered: January 2004
Karma: 0
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Senior Member |
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Yes, spring kits and adjuster kits are good and cheap to renew. We have found reusing these parts after a careful inspection can be done without degrading the work. Some of the parts are available locally, when someone works with me doing a systems restoration I provide the numbers for those parts-- thats part of the service. See it's not just the part numbers that's needed-- it's all of it, the parts, the tools, install procedures, adjustment and what to expect. That's what you should look for when you look to do something to your coach.
A good example is the question about "gravity bleeding", it's not dark rocket science and my bet is many folks here know what I'm talking about but it's getting the procedures together along with the parts, adjustment and it all. ot do a 3 way bleed there may be problems. Others may feel differently but I have found that if we do n I carry only the parts I use-- why, because I have them to use them not to just sell numbers. A local parts store may have a part but that's all you get when you plunk down your money. There is so much more to it than that. Personally, I think you get short changed when that kid behind the counter hands you a box with a part in it. There's more to it than that!
Jim Bounds
________________________________
From: Bruce Hart <hartsgmc@gmail.com>
To: gmclist@temp.gmcnet.org
Sent: Wednesday, April 17, 2013 8:54 PM
Subject: Re: [GMCnet] BRAKES!!!
One more item that always seems to get overlooked is a spring kit for the
rear brakes. Jim K has them for $13.00 for two wheels.
Most likely they are 35+ years old and have lost their tension.
http://www.appliedgmc.com/prod.itml/icOid/595
On Wed, Apr 17, 2013 at 6:20 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
> Both of mine showed this symoptom. Bleeding the front brakes properly
> cured both... the reservoir (back one strangely) had emptied and air had
> gotten in the line. I now check the reservoir much more often.
>
> --johnny
> '76 23' transmode norris
> '76 palm beach
>
> From: Patrick Fitzmorris <fitzmorrispr@gmail.com>
> To: gmclist <gmclist@temp.gmcnet.org>
> Sent: Wednesday, April 17, 2013 4:07 PM
> Subject: [GMCnet] BRAKES!!!
>
>
> My braking system is not working correctly.
>
> When I got the coach beginning of February, all was well.
>
> a couple-three weeks ago, however, I got the brake warning light,
> accompanied by the pedal doing nothing for the first half of its
> travel. I'm still able to bring the coach to a stop, but I have to
> really push hard if it's going to be a quick one. for a while, every
> other pedal push would get full braking, and the light would go back
> out. then, it was every third, then every fourth.
>
> Now, it's on much of the time. I can reliably shut the light off, and
> get normal pedal feel, but only if the parking brake is engaged.
> without the parking brake, it's once in awhile. Judging by
> temperatures and sound, its the rear brakes that I've lost. the front
> reservoir is about half full.
>
> Now I went and bought a bottle of DOT3 fluid at O'reilly, but it
> occurred to me that I don't know what the correct fluid to use is,
> aside from the old GM part number, 5464831.
>
> Any advice? i've already looked over Gene's brakes pages, and aside
> from the advice that I install a vacuum pump, and which master
> cylinder is OEM equivalent, nothing there seems terribly useful to my
> situation.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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| Re: [GMCnet] BRAKES!!! [message #206744 is a reply to message #205049] |
Fri, 03 May 2013 16:30 |
|
fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
|
Senior Member |
|
|
So, i'm planning on sourcing most if not all the brake parts locally,
because O'Reilly is five miles away, and the nearest of the Jims is
about 100 times that.
I'll be buying the hard to find stuff, like battery trays and the APC from him.
So i'm looking to find out if I've found the correct parts.
Master Cylinder
http://www.oreillyauto.com/site/c/detail/BHH2/NMC1534/01292.oap
[ interchange search for F79821 by Wagner brakes gets me these: ]
[ http://www.oreillyauto.com/site/c/detail/BEN0/11730.oap ]
[ http://www.oreillyauto.com/site/c/detail/A1C0/101534.oap ]
Wheel Cylinders: which, if any of the ones on this page will fit? I
notice they all mention 'motor home' in their descriptions...
http://www.oreillyauto.com/site/c/search/Wheel+Cylinder/01324/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
How about the flexible brake lines?
Front: Will these be correct?
http://www.oreillyauto.com/site/c/search/Brake+Hose/03349/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
Rear: Is this it?
http://www.oreillyauto.com/site/c/detail/BHH1/BH80001/03349.oap
Spring kit:
Two of these?
http://www.oreillyauto.com/site/c/detail/BHH0/H7027/01271.oap
If not, can anyone point me the right direction?
_______________________________________________
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #206758 is a reply to message #206744] |
Fri, 03 May 2013 17:56 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
|
Senior Member |
|
|
See notes below:
On May 3, 2013, at 5:30 PM, Patrick Fitzmorris <fitzmorrispr@gmail.com> wrote:
> So, i'm planning on sourcing most if not all the brake parts locally,
> because O'Reilly is five miles away, and the nearest of the Jims is
> about 100 times that.
>
> I'll be buying the hard to find stuff, like battery trays and the APC from him.
It appears that you used the wrong vehicle to search for your parts. A lot of the items are for 84 chevy 1/2T Suburan 2WD. If you were a member of GMCMI and had the parts interchange manual you would have the correct part numbers that you could reference to the OReilly parts catalog. When converting the fronts to 80MM the part numbers in the list that Ken H sent you are good numbers.
All part numbers I have listed are in the OReilly part catalog.
>
> So i'm looking to find out if I've found the correct parts.
> Master Cylinder
> http://www.oreillyauto.com/site/c/detail/BHH2/NMC1534/01292.oap
> [ interchange search for F79821 by Wagner brakes gets me these: ]
> [ http://www.oreillyauto.com/site/c/detail/BEN0/11730.oap ]
> [ http://www.oreillyauto.com/site/c/detail/A1C0/101534.oap ]
The master cylinder you want is a 10-1668 It has a 1.338 born and is the P30 master cyclinder used in most brake upgrades. It is in the OReilly catalog. I am pretty sure that the ones you have listed is way too small to do the upgrade and will not have enough fluid volumn.
Some have used the stock cylinder with larger calipers with varing success.
>
> Wheel Cylinders: which, if any of the ones on this page will fit? I
> notice they all mention 'motor home' in their descriptions...
>
> http://www.oreillyauto.com/site/c/search/Wheel+Cylinder/01324/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
For 1 1/16" wheel cylinder you want a part# WC86000 or part# 33710. For the 1 1/8" wheel cyclinder you want part# 33709. For replacement 15/16" wheel cyclinder you want part# WC51081 or part#33469
>
> How about the flexible brake lines?
>
> Front: Will these be correct?
> http://www.oreillyauto.com/site/c/search/Brake+Hose/03349/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
For the left front 88MM you want part#77320 and for the right side you want part#
> Rear: Is this it?
> http://www.oreillyauto.com/site/c/detail/BHH1/BH80001/03349.oap
If you need the rear hose for drum brakes then you need this.
http://www.appliedgmc.com/prod.itml/icOid/785
or
http://www.appliedgmc.com/prod.itml/icOid/786
All the rest of the brakes lines for drum brakes are tubing.
If your doing disk brakes then it depends on what size calipers you are using and what brand.
>
> Spring kit:
> Two of these?
> http://www.oreillyauto.com/site/c/detail/BHH0/H7027/01271.oap
You want the part#H7152 spring kit
>
> If not, can anyone point me the right direction?
> __________________________________________
JR Wright
78 Buskirk Stretch
Michigan
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] BRAKES!!! [message #206759 is a reply to message #206758] |
Fri, 03 May 2013 17:58 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
|
Senior Member |
|
|
I left out the right side front hose. part#77421
On May 3, 2013, at 6:56 PM, John Wright <powerjon@chartermi.net> wrote:
> See notes below:
>
> On May 3, 2013, at 5:30 PM, Patrick Fitzmorris <fitzmorrispr@gmail.com> wrote:
>
>> So, i'm planning on sourcing most if not all the brake parts locally,
>> because O'Reilly is five miles away, and the nearest of the Jims is
>> about 100 times that.
>>
>> I'll be buying the hard to find stuff, like battery trays and the APC from him.
>
> It appears that you used the wrong vehicle to search for your parts. A lot of the items are for 84 chevy 1/2T Suburan 2WD. If you were a member of GMCMI and had the parts interchange manual you would have the correct part numbers that you could reference to the OReilly parts catalog. When converting the fronts to 80MM the part numbers in the list that Ken H sent you are good numbers.
>
> All part numbers I have listed are in the OReilly part catalog.
>>
>> So i'm looking to find out if I've found the correct parts.
>> Master Cylinder
>> http://www.oreillyauto.com/site/c/detail/BHH2/NMC1534/01292.oap
>
>> [ interchange search for F79821 by Wagner brakes gets me these: ]
>> [ http://www.oreillyauto.com/site/c/detail/BEN0/11730.oap ]
>> [ http://www.oreillyauto.com/site/c/detail/A1C0/101534.oap ]
>
> The master cylinder you want is a 10-1668 It has a 1.338 born and is the P30 master cyclinder used in most brake upgrades. It is in the OReilly catalog. I am pretty sure that the ones you have listed is way too small to do the upgrade and will not have enough fluid volumn.
>
> Some have used the stock cylinder with larger calipers with varing success.
>>
>> Wheel Cylinders: which, if any of the ones on this page will fit? I
>> notice they all mention 'motor home' in their descriptions...
>>
>> http://www.oreillyauto.com/site/c/search/Wheel+Cylinder/01324/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
>
> For 1 1/16" wheel cylinder you want a part# WC86000 or part# 33710. For the 1 1/8" wheel cyclinder you want part# 33709. For replacement 15/16" wheel cyclinder you want part# WC51081 or part#33469
>
>>
>> How about the flexible brake lines?
>>
>> Front: Will these be correct?
>> http://www.oreillyauto.com/site/c/search/Brake+Hose/03349/C0066.oap?model=P35!s!P3500+Van&vi=1162695&year=1973&make=GMC
> For the left front 88MM you want part#77320 and for the right side you want part#
>
>> Rear: Is this it?
>> http://www.oreillyauto.com/site/c/detail/BHH1/BH80001/03349.oap
> If you need the rear hose for drum brakes then you need this.
> http://www.appliedgmc.com/prod.itml/icOid/785
> or
> http://www.appliedgmc.com/prod.itml/icOid/786
>
> All the rest of the brakes lines for drum brakes are tubing.
>
> If your doing disk brakes then it depends on what size calipers you are using and what brand.
>
>>
>> Spring kit:
>> Two of these?
>> http://www.oreillyauto.com/site/c/detail/BHH0/H7027/01271.oap
> You want the part#H7152 spring kit
>>
>> If not, can anyone point me the right direction?
>> __________________________________________
>
> JR Wright
> 78 Buskirk Stretch
> Michigan
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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