Brake Problems

[DSP]

I'm trying to get my rebuilt GLH back on the road and ran into some issues today bleeding the brakes. First off, virtually everything on the car brake related is brand new, master cylinder(24mm cast iron), stainless steel lines and hoses, calipers, wheel cylinders, drums/shoes and rotors/pads. The brake booster, prop valve and check valve were reused since they were working fine when pulled off the car originally. I kept my stock 220mm drum brakes and went with the caravan brackets/calipers/master cylinder. The calipers are on the correct side with the bleeders up. The master cylinder was bench bled prior to installation. It took a little while to push fluid through all the new lines and that is when I noticed my issue. The driver side caliper and right rear wheel cylinder appear to have bled all the air out and were working like they should when the pedal was pressed. Try as I might, the passenger side caliper and left rear wheel cylinder kept expelling a mix of fluid and pretty large bubbles when the bleeder was opened. If I remember right, the L-body's brakes are split diagonally, so it seems like my problem should be somewhere with the pass front/driver rear? The reservoir was kept filled at all times, so no air was getting in that way. I checked all the connections on the entire system and didn't find any signs of leakage. If air is getting in then shouldn't fluid be escaping somewhere? Any chance there might be some kind of issue with the proportioning valve:shrug:. Any help you all can offer will be greatly appreciated.

Dan

[tryingbe]

I would suggest you get a power bleeder and that will find that leak in a jiffy.

http://www.summitracing.com/parts/mv...FRRcfgodlmIA-w

[BIGBRUDDA]

Subscribing, as I've had the same problem with my 86 Daytona C/S, for the last year! I've bled over a gallon of fluid ,and still have only a whimpy pedal, after 6 strokes or more.

[going4speed]

on glhs 313 I originally used a new cast 1945 master cylinder. I bench bled that thing for 45 minutes and never felt like I got all the air out but finally put it on and it worked.
After that I bought a 14" wheel caravan master cylinder that are still available aftermarket in aluminum. That thing bench bled like a champ in two minutes. I dont know what the difference really is but just felt like the cast iron cylinder had a defect or something.

Oh and a power bleeder is a no brainer. Freakin' awesome!

[DSP]

on glhs 313 I originally used a new cast 1945 master cylinder. I bench bled that thing for 45 minutes and never felt like I got all the air out but finally put it on and it worked.
After that I bought a 14" wheel caravan master cylinder that are still available aftermarket in aluminum. That thing bench bled like a champ in two minutes. I dont know what the difference really is but just felt like the cast iron cylinder had a defect or something.

Oh and a power bleeder is a no brainer. Freakin' awesome!

I had the same problem, the piston firmed up a little but not like I remembered from doing one on a stock omni years ago. I have the stock master cylinder that came off the donor caravan, I think I might swap it in and give it a try. If I can find some solid brake bleeder plugs, I'll try bleeding the master cylinder that way and see if it makes a difference. I went the tubing into the reservoir route. I've been looking at power bleeders and reverse bleeders since I don't always have access to a helper. Does anyone have a recommendation for a good quality pressure bleeder that works with our master cylinders?

[going4speed]

This is the one I have:

http://www.amazon.com/dp/B000TYJEXG/..._M3T1_ST1_dp_1

[black86glhs]

The rear piston is the primary piston on that MC. That corresponds with the right front and left rear issue your having. You could be sucking in air from the rear of the master cylinder. TRy swapping the other MC and see if it fixes it. You would think it would leak from there and it may be, but you can't see it or just hasn't shown up yet.

[DSP]

I'm going to put the car on hold for a few days. It's all of 12 degrees now and supposed be be single digits in the evening and I don't have anywhere heated to work on it. Plus my lovely assistant is refusing to sit in a freezing car and pump the brakes and everyone else is suddenly busy. I'm going to pick up one of the power bleeders so I can just bleed them myself, then everyone will be happy. Either that or teach the dog how to pump the brake pedal, she's the only one who enjoys working with dummy out in the cold.

[looneytuner]

I just bought some bleeder screws that are spring loaded for 1 person bleeding. Open 1 up and pump, then close it. It works like a tire valve in reverse. It will bleed but not let air in when you release the pedal. I think you should be able to get them at Amazon or Jegs.

[tryingbe]

I just bought some bleeder screws that are spring loaded for 1 person bleeding. Open 1 up and pump, then close it. It works like a tire valve in reverse. It will bleed but not let air in when you release the pedal. I think you should be able to get them at Amazon or Jegs.

Trust me, once you used the power bleed, you'll never go back to pumping the brake.

[Tbird232ci]

Is the master cylinder new or is it remanufactured?

[DSP]

Is the master cylinder new or is it remanufactured?

The master cylinder was brand new.
Well, problem is fixed. It warmed up to the low 30's, so I put on my shorts and t-shirt and decided to work on the car(It's pretty sad when freezing feels really warm). I re-bled the old caravan master cylinder using 1-way check valves (worked far better than plugs or hoses looped back into the reservoir) then hooked it up and bled using a power bleeder I picked up. I should have bought one of those things years ago, man does it make bleeding the brakes quicker and easier. A lot of air came out of the RF/LR then it started pushing clear fluid. I re-bled everything again just to make sure, topped off the reservoir and checked the pedal. Presto, very firm pedal and everything seems to be working perfectly. I believe the culprit was the new master cylinder. When I took it off I bled it again on the bench with the check valves and a small amount of air came out, but I noticed the cylinder bore seemed to be pretty "wet." I had to pump it quite a few times, but I was able to get a very small amount of fluid leak out the back of the master cylinder. It would appear that one of the seals in the master cylinder is bad. I was really paranoid about not pushing the piston in too far when I was bleeding it the first time, so I know it was not bottomed out. Maybe it was dried out from sitting on the shelf for so many years? Whatever the reason, all I know is that I have good brakes now and that's fine with me.

[Tbird232ci]

Power bleeders are a godsend. I bought one when I did the CTSV brakes on the front of my Trans Am and it made bleeding the brakes a breeze. Which adapter do you have? I need to order one for my Dodge.

[black86glhs]

The master cylinder was brand new.
Well, problem is fixed. It warmed up to the low 30's, so I put on my shorts and t-shirt and decided to work on the car(It's pretty sad when freezing feels really warm). I re-bled the old caravan master cylinder using 1-way check valves (worked far better than plugs or hoses looped back into the reservoir) then hooked it up and bled using a power bleeder I picked up. I should have bought one of those things years ago, man does it make bleeding the brakes quicker and easier. A lot of air came out of the RF/LR then it started pushing clear fluid. I re-bled everything again just to make sure, topped off the reservoir and checked the pedal. Presto, very firm pedal and everything seems to be working perfectly. I believe the culprit was the new master cylinder. When I took it off I bled it again on the bench with the check valves and a small amount of air came out, but I noticed the cylinder bore seemed to be pretty "wet." I had to pump it quite a few times, but I was able to get a very small amount of fluid leak out the back of the master cylinder. It would appear that one of the seals in the master cylinder is bad. I was really paranoid about not pushing the piston in too far when I was bleeding it the first time, so I know it was not bottomed out. Maybe it was dried out from sitting on the shelf for so many years? Whatever the reason, all I know is that I have good brakes now and that's fine with me.

Hey, I'm not completely full of crap! Sweet.

[DSP]

Power bleeders are a godsend. I bought one when I did the CTSV brakes on the front of my Trans Am and it made bleeding the brakes a breeze. Which adapter do you have? I need to order one for my Dodge.

This is the one you need: http://www.jegs.com/i/Motive+Products/715/1103/10002/-1

[DSP]

Hey, I'm not completely full of crap! Sweet.

Yep, master cylinder seems to be the culprit. I think it's ridiculous that a 28 year old used master cylinder is in better working condition than a new unused U.S. made cylinder.

[black86glhs]

I wonder if you are right and the seal dried out from sitting.