Home » Public Forums » GMCnet » [GMCnet] BRAKES!!!
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| Re: [GMCnet] BRAKES!!! [message #206876 is a reply to message #206776] |
Sun, 05 May 2013 12:53   |
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fitzmorrispr
Messages: 137
Registered: February 2013
Location: Los Angeles
Karma: 0
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gene, those are indeed excellent prices, however, i'm not upgrading to
discs just yet. It'll probably be several years.
JR, I'm not upgrading my calipers at all, I want an OEM style MC. Are
any of the ones I mentioned good for that?
As for the wheel cylinders, I was gonna go OEM style. Would that be
the 15/16"? Is that used on all four rear wheels?
Any particular reason to switch?
also, those part numbers return Bendix branded hoses for the front
wheel hoses, which /look/ just like the ones I linked. I guess I'll
have the shop order both so we can compare them.
(i'll note that I searched under '1973 GMC P35/P3500 Van' which seems
to be the same as the Chevy P30)
A., the prices may be close, but I'll take $9.99 and five miles away
over $12.50 and 500 miles away.
It's stuff like the rear brake hoses that i'll order from Applied.
Jim's a pretty great guy, and he's got lots of expertise and
inventory, but he's a long ways away from L.A.
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #206930 is a reply to message #206908] |
Sun, 05 May 2013 23:44 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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A 3" wide shoes does not really improve from an engineering side as
coefficient of friction is what matters , not the area.
The reason why you will notice the difference, is that the lining material
of the 3" is very good one and the shoes are now touching on an area that
is not glazed.
Matt Collie's coach responded considerably better after the Drum/ Drum
Reaction Arm was installed there.
It was a good comparison of standard to the one with reaction arm as Matt
drove down and knew its capability before and now with the system using the
same brakes.
On Sun, May 5, 2013 at 5:37 PM, A. <markbb1@netzero.com> wrote:
>
>
> ljdavick wrote on Sun, 05 May 2013 17:10
> > The price for the drum brake reaction arm is pretty compelling. If they
> offer much of the benefit of the disk reaction arm and have 4 parking
> brakes to boot then this might be the way to go for me. I have no data to
> support it, but I suspect that 2 big disks and 4 big drums would be plenty
> of braking for these coaches. Disks would help prevent fade and are always
> "adjusted" but those benefits are secondary to me.
> > Is my thinking flawed?
> If my financial situation ever allows it, I will buy a drum brake reaction
> arm kit, because I don't believe disk brakes are necessary or desirable on
> the rear of a GMC motorhome.
>
> If I fell into a lot of money, I would add Tom Hampton's "Better Brakes"
> rear shoes and wheel cylinders to the rear drum reaction kit, and then add
> 80MM calipers to the front. I estimate that would about double the amount
> of energy the brakes could dissipate (while preserving the balance
> front-to-back), with a corresponding reduction in stopping distance.
>
> Then all we need is someone to engineer a cost effective anti-lock braking
> system...
> --
> '73 23' Sequoia For Camping
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> "Time is money. If you use YOUR time, you get to keep YOUR money."
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] BRAKES!!! [message #206931 is a reply to message #206930] |
Sun, 05 May 2013 23:51 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Pat,
I would check out the Master Cylinder as that seems to be creating he
differential pressure, also there can be a wheel cylinder leaking.
Pop off the wheels first and see that the wheel cylinders are good.
No use spending money unless you desire more than a good standard brake.
On Sun, May 5, 2013 at 9:44 PM, Jim Kanomata <jimkanomata@gmail.com> wrote:
> A 3" wide shoes does not really improve from an engineering side as
> coefficient of friction is what matters , not the area.
> The reason why you will notice the difference, is that the lining material
> of the 3" is very good one and the shoes are now touching on an area that
> is not glazed.
> Matt Collie's coach responded considerably better after the Drum/ Drum
> Reaction Arm was installed there.
> It was a good comparison of standard to the one with reaction arm as Matt
> drove down and knew its capability before and now with the system using the
> same brakes.
>
>
>
> On Sun, May 5, 2013 at 5:37 PM, A. <markbb1@netzero.com> wrote:
>
>>
>>
>> ljdavick wrote on Sun, 05 May 2013 17:10
>> > The price for the drum brake reaction arm is pretty compelling. If they
>> offer much of the benefit of the disk reaction arm and have 4 parking
>> brakes to boot then this might be the way to go for me. I have no data to
>> support it, but I suspect that 2 big disks and 4 big drums would be plenty
>> of braking for these coaches. Disks would help prevent fade and are always
>> "adjusted" but those benefits are secondary to me.
>> > Is my thinking flawed?
>> If my financial situation ever allows it, I will buy a drum brake
>> reaction arm kit, because I don't believe disk brakes are necessary or
>> desirable on the rear of a GMC motorhome.
>>
>> If I fell into a lot of money, I would add Tom Hampton's "Better Brakes"
>> rear shoes and wheel cylinders to the rear drum reaction kit, and then add
>> 80MM calipers to the front. I estimate that would about double the amount
>> of energy the brakes could dissipate (while preserving the balance
>> front-to-back), with a corresponding reduction in stopping distance.
>>
>> Then all we need is someone to engineer a cost effective anti-lock
>> braking system...
>> --
>> '73 23' Sequoia For Camping
>> '73 23' CanyonLands For Sale
>> UA (Upper Alabama)
>> "Time is money. If you use YOUR time, you get to keep YOUR money."
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] BRAKES!!! [message #208612 is a reply to message #205041] |
Thu, 23 May 2013 05:58 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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| Ken Burton wrote on Thu, 18 April 2013 04:04 |
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.
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Ken, do you know why you would to go to 1 1/16" brake cylinder for the middle wheels and 15/16" for the rear wheels. I also found it listed in the Brake Info list set from Mr.Fisher.
Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] BRAKES!!! [message #208629 is a reply to message #208612] |
Thu, 23 May 2013 09:06 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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To keep the rear/rear tires from locking up on heavy braking.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On May 23, 2013 3:59 AM, "Bruce Hart" <hartsgmc@gmail.com> wrote:
>
>
> Ken Burton wrote on Thu, 18 April 2013 04:04
> > 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, do you know why you would to go to 1 1/16" brake cylinder for the
> middle wheels and 15/16" for the rear wheels. I also found it listed in
> the Brake Info list set from Mr.Fisher.
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> _______________________________________________
> 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 #208630 is a reply to message #206966] |
Thu, 23 May 2013 09:22 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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| A Hamilto wrote on Mon, 06 May 2013 11:21 |
| jimk wrote on Sun, 05 May 2013 23:44 |
A 3" wide shoes does not really improve from an engineering side as coefficient of friction is what matters , not the area.
The reason why you will notice the difference, is that the lining material of the 3" is very good one and the shoes are now touching on an area that is not glazed.
Matt Collie's coach responded considerably better after the Drum/ Drum Reaction Arm was installed there.
It was a good comparison of standard to the one with reaction arm as Matt drove down and knew its capability before and now with the system using the same brakes.
|
Tom Hampton's kit includes larger wheel cylinders for increased pressure on those 3" shoes. A reaction arm on that setup would be nirvana.
|
Bigger shoes helps 2 things;
1. Pad life
2. Bake fade
Cold stopping is not changed
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] BRAKES!!! [message #208642 is a reply to message #208612] |
Thu, 23 May 2013 13:58 |
Ronald Pottol
Messages: 505
Registered: September 2012
Location: Redwood City, California
Karma: -2
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Senior Member |
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Under braking the middle wheels are pressed into the pavement and the rear
wheels are lifted by the brakes effect on the bogies. This is the same
thing as shaft drive effect on a motorcycle. The reaction arm systems are
like BMWs paralever on their shaft drive motorcycles, effectively
eliminating it.
Pressed down allows for more braking, lifted, less.
On May 23, 2013 3:59 AM, "Bruce Hart" <hartsgmc@gmail.com> wrote:
>
>
> Ken Burton wrote on Thu, 18 April 2013 04:04
> > 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, do you know why you would to go to 1 1/16" brake cylinder for the
> middle wheels and 15/16" for the rear wheels. I also found it listed in
> the Brake Info list set from Mr.Fisher.
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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1973 26' GM outfitted
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| Re: [GMCnet] BRAKES!!! [message #208644 is a reply to message #208635] |
Thu, 23 May 2013 14:12 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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| A Hamilto wrote on Thu, 23 May 2013 11:44 |
| Keith V wrote on Thu, 23 May 2013 09:22 |
Bigger shoes helps 2 things;
1. Pad life
2. Brake fade
Cold stopping is not changed
|
Your statement applies to brakes with a fixed cylinder size when only the width of the pad/shoe is increased without changing the cylinder size.
A larger wheel cylinder will increase the pressure on the shoes.
That increased pressure applied to the shoes will either cause more energy dissipation (shortening stopping distance) or will lock up and slide the wheels (possibly lengthening stopping distance).
Tom Hampton's kit CAN (probably WILL) change cold stopping distance.
|
I said nothing about brake slave cylinder size.
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] BRAKES!!! [message #208661 is a reply to message #208612] |
Thu, 23 May 2013 18:35 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Bruce Hart wrote on Thu, 23 May 2013 05:58 |
| Ken Burton wrote on Thu, 18 April 2013 04:04 |
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, do you know why you would to go to 1 1/16" brake cylinder for the middle wheels and 15/16" for the rear wheels. I also found it listed in the Brake Info list set from Mr.Fisher.
|
The reason for the difference in the middle and rear wheel cylinders sizes is to try to reduce the rear tires from locking up under heavy braking. You are also correct. I did use 15/16" rear cylinders NOT 7/8" cylinders on the rear wheels.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] BRAKES!!! [message #208733 is a reply to message #208661] |
Fri, 24 May 2013 15:06 |
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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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So guys. I bled the rear brakes and it improved reliability greatly,
but not quite to 100%. I thought the remaining deficit was the result
of a failure to properly tighten the right rear rear screw all the way
before doing the left side. However, the braking quality seems to be
decaying back to the way it was before I did that work, which suggests
it's a different, as-yet-uncorrected, problem.
I guess it's time to do it the hard way.
On Thu, May 23, 2013 at 4:35 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Bruce Hart wrote on Thu, 23 May 2013 05:58
>> Ken Burton wrote on Thu, 18 April 2013 04:04
>> > 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, do you know why you would to go to 1 1/16" brake cylinder for the middle wheels and 15/16" for the rear wheels. I also found it listed in the Brake Info list set from Mr.Fisher.
>
> The reason for the difference in the middle and rear wheel cylinders sizes is to try to reduce the rear tires from locking up under heavy braking. You are also correct. I did use 15/16" rear cylinders NOT 7/8" cylinders on the rear wheels.
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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The Greatfruit: 1973, 26', Canyon Lands or Painted Desert, in Pineapple Yellow
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| Re: [GMCnet] BRAKES!!! [message #359075 is a reply to message #204963] |
Mon, 28 September 2020 22:52 |
LarryInSanDiego
Messages: 336
Registered: September 2006
Karma: 0
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Senior Member |
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Dredging up an old thread, but I have this question: If I go with the drum reaction arm system, is the upsize on the rearmost axle to 1 1/16" even an advantage anymore? Or would sticking to 15/16" on all four WITH the reaction arm system better as all the rear wheels have the same "weight" on them? I also noticed that the oversize wheel cylinder requires bending the brake line. Is the 1 1/16" wheel cylinder available with the same brake line mounting angle as the stock 15/16" ones?
Larry Engelbrecht
San Diego, CA
'73 26' ex-Glacier
TZE063V100319 03/07/73
[Updated on: Mon, 28 September 2020 22:53] Report message to a moderator |
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