Home » Public Forums » GMCnet » [GMCnet] FW: Still dealing with Brakes
| [GMCnet] FW: Still dealing with Brakes [message #278685] |
Fri, 29 May 2015 22:22  |
Neil Fonville
Messages: 68
Registered: May 2014
Karma: 0
|
Member |
|
|
About to the point of just selling out and be done. Spent 15 hours installing 4 wheel disc brakes on the rear and about as much time getting the coaches brakes to actually work. Working is a pretty loose term here too. After getting the kit installed, I have really no braking. Spent ton of time bleeding with various methods. Then, I installed a new master cylinder 34 mm model from O'riley and a new all disc PV4 combiner valve. Spend the last 6 hours bleeding. Not much better. I bleed with a suction bleeder from Harbor Freight. Ran a quart of fluid through and no bubbles. Brakes are worse than when I started. I can't think there is air in the system at this point. Dumped $1800 in parts and lots of time. Frustrated that there is no qualified mechanics in the DFW area to help maintain my coach. The person referred by local GMCers lives in Athens 60 miles away. Not practical as he has a full time job and does not have time for big projects. The thrill is now gone an
d I'm about to fire sell a nice GMC II with no brakes. Any idea what needs to be the next step to get this thing back on the road? Where is the closest place to get someone qualified to get this coach fixed?
Frustrated GMC owner in DFW
Neil Fonville
Allen, TX
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
1975 GMC II
Allen, TX
|
|
|
|
| Re: [GMCnet] Still dealing with Brakes [message #278686 is a reply to message #278685] |
Fri, 29 May 2015 23:08  |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
|
Senior Member |
|
|
Neil,
I’ve been there. Well, in the neighborhood of there, but never to the tune of $1,800… I have had very good success with the cheapie Harbor Freight vacuum sucker but I just have a feeling in my bones that pressure bleeding is different than suction bleeding. All I can figure is that with pressure bleeding all the braking components are at their maximum, pad permitting, and maybe there is some place for air to hide when retracted.
I could be blowing air - but know that many of us have been frustrated by these baby’s too. It’ll be sweet when it works.
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
> On May 29, 2015, at 8:22 PM, Neil Fonville wrote:
>
> About to the point of just selling out and be done. Spent 15 hours installing 4 wheel disc brakes on the rear and about as much time getting the coaches brakes to actually work. Working is a pretty loose term here too. After getting the kit installed, I have really no braking. Spent ton of time bleeding with various methods. Then, I installed a new master cylinder 34 mm model from O'riley and a new all disc PV4 combiner valve. Spend the last 6 hours bleeding. Not much better. I bleed with a suction bleeder from Harbor Freight. Ran a quart of fluid through and no bubbles. Brakes are worse than when I started. I can't think there is air in the system at this point. Dumped $1800 in parts and lots of time. Frustrated that there is no qualified mechanics in the DFW area to help maintain my coach. The person referred by local GMCers lives in Athens 60 miles away. Not practical as he has a full time job and does not have time for big projects. The thrill is now gone an
> d I'm about to fire sell a nice GMC II with no brakes. Any idea what needs to be the next step to get this thing back on the road? Where is the closest place to get someone qualified to get this coach fixed?
>
> Frustrated GMC owner in DFW
> Neil Fonville
> Allen, TX
> _______________________________________________
> 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
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278688 is a reply to message #278685] |
Sat, 30 May 2015 01:05 |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
|
Senior Member |
|
|
Neil Fonville wrote on Fri, 29 May 2015 22:22About to the point of just selling out and be done. Spent 15 hours installing 4 wheel disc brakes on the rear and about as much time getting the coaches brakes to actually work. Working is a pretty loose term here too. After getting the kit installed, I have really no braking. Spent ton of time bleeding with various methods. Then, I installed a new master cylinder 34 mm model from O'riley and a new all disc PV4 combiner valve. Spend the last 6 hours bleeding. Not much better. I bleed with a suction bleeder from Harbor Freight. Ran a quart of fluid through and no bubbles. Brakes are worse than when I started. I can't think there is air in the system at this point. Dumped $1800 in parts and lots of time. Frustrated that there is no qualified mechanics in the DFW area to help maintain my coach. The person referred by local GMCers lives in Athens 60 miles away. Not practical as he has a full time job and does not have time for big projects. The thrill is now gone an
d I'm about to fire sell a nice GMC II with no brakes. Any idea what needs to be the next step to get this thing back on the road? Where is the closest place to get someone qualified to get this coach fixed?
Frustrated GMC owner in DFW
Neil Fonville
Allen, TX
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Neil,
You didn't say anything about bleeding the master cylinder. If not, then bench bleed the MC is first. Make 2 tubes from outlets and bent to reach into the fluid of the reservoirs (when bleeding don't let the end of the tubes get exposed). With the MC in vice, cycle the piston at a moderate rate until there's only clear fluid
being cycled. Now mount the MC, don't drain or remove bleed tubes jet, when mounted remove one bleed tube at the time to connect the brake tube, and top off the MC.
The next step is best accomplished with a power bleeder, it provides fluid pressure and volume to push the air out. Figure on bleeding the system twice to make sure all air is out, and it may take 2 qts to do it. I don't reuse bleed fluid, possible contamination.
Start bleeding from the farthest point from the MC, right rear, then right front, left rear, left front. I use clear jar with a hose into fluid as an air lock.
Make sure that the vacuum seal that's between the booster and MC is still there, or the booster won't work.
I've never have had success with a suction bleeding, lack of fluid volume and speed of fluid through the tubes.
For the pressure pot I used a 1/2 gal. garden sprayer and made the MC cover. Jim Hupy makes covers and ?.
Hopefully this will bring you over the hump. Be persistent, don't give up.
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
[Updated on: Sat, 30 May 2015 01:12] Report message to a moderator |
|
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278694 is a reply to message #278688] |
Sat, 30 May 2015 06:25 |
Neil Fonville
Messages: 68
Registered: May 2014
Karma: 0
|
Member |
|
|
Thanks everyone. I have actually had a chance to sleep on it and my frustration level is now under control and back to rational thinking. So a few questions.
I will go back a bench bleed the MC because that will help determine if it is defective. I did buy a "new" one and not reman but who knows. Did I get the correct or best part for the job? I used part number Oriley's part number NMC1668.
http://www.oreillyauto.com/site/c/search.oap?keyword=nmc1668
The friend helping me wondered if having the block behind the pedal is restricting the pedal throw to not allow enough pressure to build when pump bleeding? I have a small block of 2x4. Is that necessary with this MC model? Can you blow the seal out on it or is this just necessary on the OEM MC?
Also, I beat the mounting bracket flat and mounted the MC in front of the bracket. I was expecting the pedal to have a slight soft feel for say the first 2% of pedal movement and then stiff up with braking action beginning. The push rod length being 2mm (thickness of the bracket) or so too short. Is that expectation correct? Currently the pedal goes to at least 50% of pedal movement before any braking action begins when the coach is moving. It does not take near as much when we have the wheels off and see the calipers close.
Glad to hear the vacuum bleed was not useful to others. I just assumed since I was getting a clean solid stream of fluid that meant no air. I guess that's a bad assumption and there can be air pockets in the system because the pressure is too low to suck the air out?
Brake fluid is cheap. I have used 4 quarts in the process and will use another 4 if that what it takes.
Last question. If my local brake and muffler shop has a bleeder that pushes fluid from the caliper to the MC, is that better than the pressure bleeder?
Sure love this GMC but sometimes it's like your kids. You just can't control all it's actions and outcomes but you sure do love them.
Thanks again.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
1975 GMC II
Allen, TX
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278695 is a reply to message #278685] |
Sat, 30 May 2015 06:33 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
|
Senior Member |
|
|
these stories I read now and again just bum me out. It should not be this difficult.
You have already spent $1800.00, spend another $75+ shipping on Jim Hupy's bleeder:
http://bdub.net/jhupy/
I am almost certain if you bleed using his bleeder, then you can almost certain troubleshoot everything else but air in the system. Plus less frustration with any other bleeding method.
to give you an example on how well I think it works, I have had a leak in my rear drums for a while(maybe 2 summers). I just check the fluid before I leave, and top it off. Well, something changed, and when i went to leave last friday, I checked the fluid and the reservoir for the rear brakes (front) was empty. It usually is at most 1/2 down, but my coach has been sitting for 6-8 weeks. I filled it up, tested the brakes and for sure I had not much of a peddle.
I hooked up the Jim hupy bleeder(maybe 3-5 minutes) cracked the bleeders. and I had my pedal back and I was in business again in about 10-15 minutes. after a couple hundred mile weekend, my reservoir is still topped off, so not sure what is up. I ordered all new rear brake parts, and will be rehabbing the rear in the next week.
I have piece mealed my braking system since I have owned my coach. not smart, but after buying that pressure bleeder, I can't see how I have lived without it for so many years. I have not yet, once not finished a 10 minute bleeding job with it and not had a solid good pedal, or issue with any air in the line. I have bleed my gmc maybe 5-10 times. a couple jeep wranglers. and 2-3 other misc. vehicles.
There is tons of coaches out there that stop plenty well. try not to let this discourage you.
I don't know what you have going with the modified braking system. The only other thing that can be hard to diagnose, is the right push rod for whatever booster/master cylinder setup you have that might throw things off.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
[Updated on: Sat, 30 May 2015 06:35] Report message to a moderator |
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278696 is a reply to message #278694] |
Sat, 30 May 2015 06:53 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Neil,
There are a number of possible issues regarding your brake situation, but
the first one is clear: Your Booster-to-MC push rod is too short by at
least 0.100" -- the thickness of the bracket you mounted between the
booster and the MC. Here's one way to measure the length you need to make
a replacement pushrod:
http://www.gmcmhphotos.com/photos/g6289-master-cylinder-pushrod-gauge.html
If you don't want to fool with that, you can go the "modeling clay" route
-- put a dab of that on the end of the OEM pushrod, re-mount the MC
temporarily, then measure the length to which the clay is deformed. Take
about 0.005" off of that dimension for the new pushrod. Be sure the
profiles of the ends of the replacement match the original. DO NOT make it
too long or your brakes will lock up.
You say braking action begins at 50% pedal travel. With the short push rod
and new, unseated pads, I don't consider that abnormal. If the coach
stops, you need to drive it to "bed in" the pads. The pedal height and
braking action will continue to improve for at least 1000 miles (at least
it takes that long with my light braking habits).
Let us know what the situation is after you install a long-enough push rod.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com
On Sat, May 30, 2015 at 7:25 AM, Neil Fonville wrote:
> Thanks everyone. I have actually had a chance to sleep on it and my
> frustration level is now under control and back to rational thinking. So a
> few questions.
>
> I will go back a bench bleed the MC because that will help determine if it
> is defective. I did buy a "new" one and not reman but who knows. Did I
> get the correct or best part for the job? I used part number Oriley's part
> number NMC1668.
> http://www.oreillyauto.com/site/c/search.oap?keyword=nmc1668
>
> The friend helping me wondered if having the block behind the pedal is
> restricting the pedal throw to not allow enough pressure to build when pump
> bleeding? I have a small block of 2x4. Is that necessary with this MC
> model? Can you blow the seal out on it or is this just necessary on the OEM
> MC?
>
> Also, I beat the mounting bracket flat and mounted the MC in front of the
> bracket. I was expecting the pedal to have a slight soft feel for say the
> first 2% of pedal movement and then stiff up with braking action
> beginning. The push rod length being 2mm (thickness of the bracket) or so
> too short. Is that expectation correct? Currently the pedal goes to at
> least 50% of pedal movement before any braking action begins when the coach
> is moving. It does not take near as much when we have the wheels off and
> see the calipers close.
>
> Glad to hear the vacuum bleed was not useful to others. I just assumed
> since I was getting a clean solid stream of fluid that meant no air. I
> guess that's a bad assumption and there can be air pockets in the system
> because the pressure is too low to suck the air out?
>
> Brake fluid is cheap. I have used 4 quarts in the process and will use
> another 4 if that what it takes.
>
> Last question. If my local brake and muffler shop has a bleeder that
> pushes fluid from the caliper to the MC, is that better than the pressure
> bleeder?
>
> Sure love this GMC but sometimes it's like your kids. You just can't
> control all it's actions and outcomes but you sure do love them.
>
> Thanks again.
>
>
> _______________________________________________
> 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
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278701 is a reply to message #278697] |
Sat, 30 May 2015 08:17 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Remove the MC, grab the rounded end of the shiny push rod, and pull. It's
about 2.5" long, flat on the hidden end. Should fit snugly in the plastic
push rod (which will also pull out, but needn't).
Ken H.
On Sat, May 30, 2015 at 8:03 AM, Neil Fonville wrote:
> So now the really dumb question. How do you remove the push rod?
>
> I¹ll either build or acquire the Hupy bleeder for sure.
>
> _______________________________________________
> 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
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278704 is a reply to message #278685] |
Sat, 30 May 2015 08:47 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
|
Senior Member |
|
|
I had a similar situation in November-December of 2014, when I went to a new sensitized booster. At the same time I choose to put in a new/rebuilt MC. I choose the same 34mm MC that you had listed from O"Reily's, but got it from AutoValue. I spent many hours trying to bleed the brakes with poor results...meaning that I had low pedal and poor brakes. I removed the MC for another bench bleed. When bleeding, I found that I was able to bleed the rear piston in the cylinder...good flow of fluid when depressing the pushrod. But none or very little flow from the front piston. I returned it to AutoValue in exchange for another one that they had to get from another store. Same problem. They gave me another one and that 3rd one also would not bench bleed. I brought it into AutoValue and had the counter person (a former mechanic...a known good mechanic) try to bleed it. He had the same issue of not being able to bench bleed the forward piston. So, they got me another one from another store. Two more MC"s and still no comple bleeding. I finally borrowed a known good MC (GMC original, not the 34mm style) and installed it. Braking problems gone!! Good pedal, and good brakes. So, I called Dave L and spent some time talking with him about this. Found out that he had a identical problem with bleeding the 34mm while trying to put together a demonstration bench for a GMCMI rally tech session. He could not bleed the front piston in the MC. He finally got a long bar and using some built in leverage, was finally able to break the front piston loose. It then bled fine and worked fine on his demo bench.
I concluded from this whole experience that because of the age of the vehicles involved, that these MC's are not movers in terms of sales, so many of them are MC's that have been sitting on part store shelves for years. During that time the seals and pistons have corroded and frozen in the bore. Dave was able to put enough leverage and pressure on his to finally break it loose, and it then worked properly.
So, what I'm saying here is that there is a good possibility that your rebuilt MC is the problem. So, are you getting a good bench bleed from the MC from both the front and rear pistons? Is there good flow from BOTH recirculation tubes while bench bleeding? If not, you may have a bad MC, with the front piston frozen in the bore. It is not good enough to put enough pressure on the pushrod to "break it loose" because then you have a issue with corrosion that may (sooner than later) take out that seal and render the MC useless.
So, my suggestion is find a known working MC. Bench bleed it and install it. If an known good MC works and solves your bleeding and braking issues...well...you gotta find a MC that bench bleeds from both front and rear pistons on the first push of the pushrod. You may have to return as many as is necessary to get one that bleeds right up front.
Just what I'd do...
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
|
|
|
|
|
|
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278733 is a reply to message #278723] |
Sat, 30 May 2015 16:00 |
Neil Fonville
Messages: 68
Registered: May 2014
Karma: 0
|
Member |
|
|
Update: I went back out today with a clearer head. I pulled the MC and
redid the bench bleed watching it very closely. As others had
experienced, my front chamber was not pushing the same amount of fluid.
On the back chamber when pressing the plunger (not sure that¹s the right
name), I got bubbles of air about the first 10 times. Then a smooth
steady stream. The front would never quit bubbling air even after at
least a hundred cycles and almost no fluid flowed. Tomorrow I will
installed the new MC after confirming it works and is bleed. I¹ll report
back. Thanks for all the input. Lots of good info from this community.
Neil
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
1975 GMC II
Allen, TX
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278754 is a reply to message #278733] |
Sat, 30 May 2015 23:10 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
|
Senior Member |
|
|
On all of the master cylinders I have replaced in the past 40 years, I cannot recall any that had any type of bracket between the master cylinder and the booster. It would violate the vacuum seal and make the brake actuation too far down in the pedal travel. Is this the way you have it installed or am I misunderstanding your mounting description? I haven't looked at mine since reading this thread, and if there is a bracket between the M/C and the booster, I will be really surprised and then stand corrected with a boot to the head...
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
|
|
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278761 is a reply to message #278754] |
Sun, 31 May 2015 05:54 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
Terry,
You are correct.
Check Maintenance Manual X-7525 / Section 5 - Brakes / Page 5-20 / Figure 14 and 15 and you can see that the bracket goes on top of
the master cylinder mounting flanges.
Parts Book 78Z / Section 4 - Brakes / Page 4 - 6 / Figure 4.005 Pedal - Brake (incl. Shaft) shows the same thing.
However, when one installs four additional calipers on the rear wheels the OEM master cylinder does not provide enough fluid when
the brake pedal is depressed to feed six calipers. To obtain more fluid a P-3 master cylinder is used.
The OEM bracket interferes with the P-3 master cylinder so you need to beat it flat or buy a kit like this:
http://www.appliedgmc.com/prod.itml/icOid/1016
Which as you can see comes with a flat bracket.
You are correct placing the bracket between the P-3 master cylinder and the booster violates the vacuum seal.
If you check Parts Book 78Z / Section 4 - Brakes / Page 4 -8 Booster - Power Brake / Key 9 / Part Number 5460935 / Description -
Seal you will see it is cup shaped. That cup shaped seal is virtually impossible to find. That seal performed two functions; 1)
sealed the vacuum 2) located the master cylinder in the center of the booster.
http://shop.docrebuild.com/1963-1967corvettepbfrontshellsealoriginalgm18005270.aspx
or
http://shop.docrebuild.com/1963CorvettePBFrontShellSealOriginalGM5460935.aspx
Note that it is the same part number as the one in 78Z but it is NOT cup shaped!
BTW this guy won't sell to you unless you have a Corvette! I tried to order a 5460935 from him and he cancelled the order.
If you have any connections and could find the cup shaped seals it would be great!
Oh yeah, Dave Lenzi uses the 5460935 flat type and machines a thin walled spacer that goes around the tail shaft of the master
cylinder and centers it and pushes the seal all the way down in the booster's bore. He does NOT sell those parts separately they
come with any booster he rebuilds.
Regards,
Rob M.
-----Original Message-----
From: Terry
On all of the master cylinders I have replaced in the past 40 years, I cannot recall any that had any type of bracket between the
master cylinder and the booster. It would violate the vacuum seal and make the brake actuation too far down in the pedal travel. Is
this the way you have it installed or am I misunderstanding your mounting description? I haven't looked at mine since reading this
thread, and if there is a bracket between the M/C and the booster, I will be really surprised and then stand corrected with a boot
to the head...
--
Terry
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278775 is a reply to message #278761] |
Sun, 31 May 2015 11:25 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
|
Senior Member |
|
|
And I have a couple of those cup seals in my boxes of caps and plugs...didn't know they were hard to find, but saved them because I'm a pack rat and rarely throw anything away. Think I got them from a Lincoln Town Car and some kind of import that I replaced the boosters on years ago. Don't know if they would fit the GMC, but I do know they didn't come from one.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278777 is a reply to message #278685] |
Sun, 31 May 2015 12:29 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
|
Senior Member |
|
|
Neil,
Your description of bench bleeding the mc where you continue to get air bubbles is something I have seen before. A recommendation I got in that situation was to put a plug in the rear chamber once it is properly blend. This allows more fluid to flow to the front chamber. I had that situation on my 69 Chevy work truck. Once I plugged the rear chamber the front chamber finally bench bled properly with no bubbles.
I spent a few weeks on my GMC brakes before everything came together. You will get there.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
|
|
|
|
| Re: [GMCnet] FW: Still dealing with Brakes [message #278780 is a reply to message #278777] |
Sun, 31 May 2015 12:39 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
|
Senior Member |
|
|
Steve is right, have had to do that on a few bench bleeds. No rhyme or reason, just some refused to completely bleed without plugging that port. I guess they need the pressure built up in the rear system in order to fully compress the front system.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
|
|
|
|
Goto Forum:
Current Time: Sat Nov 16 01:37:09 CST 2024
Total time taken to generate the page: 0.01192 seconds
|
GMCforum
Search
Help
Register
Login
Home
