Brakes are Kicking my BUTT, Help Please

[UpHill1]

I have a brake problem that is kicking my butt on a 1979 CJ5 . I have tried to keep this as short and too the point as possible.

Last fall the wife and I are out for a cruise and I go to stop and the Jeep pulled hard left, right over the center line. I get safely stopped and do a visual and all looks fine. I am about 5 miles from home and took it slow. Got home and you could smell the brakes. I lifted the left side and you could not turn the wheel.

Let it cool down and removed the wheel to expose a broken inner brake pad wedged in tight. I decided go through all the front brakes, hubs and axle. I replaced the bearings, seals, rotors, calipers, pads and front brake lines on both sides. I purchased all the brake components from Morris 4 x 4.

I bench bleed the master and got everything buttoned up, but could NOT get the front to bleed for anything. Just when I thought I had it a short run had the brakes on and hot.

I started looking at the master cylinder and booster. Replaced both from Morris 4 x 4, flushed to bottles of brake fluid through the entire system. SAME PROBLEM after they heat up. This led me to believe there had to be air in the lines and also the pedal was a little soft until you pumped it a few times. I decided to also change out the proportional valve. I have bleed RR, LR, RF, LF and also RF, LF, RR, LR.

Fast forward and a friend told me the bleeder valves need to be at 12 o’clock to get all the air out. So I pull both the front ones off the rotors and using a c-clamp bleed them again. Guess what there was a LOT of air in the system.

Now I can jack the front tires off the ground and they spin fairly freely as normal. However my pedal has zero slack and within three miles the Jeep is stopping itself when you left off the gas. Jack it up and the front wheels will not turn by hand.

Today I looked at the brake booster push rod. The rod between the brake pedal and the bracket on the firewall is fixed. It cannot be adjusted. The tip of the push rod out of the booster can extend longer but cannot go shorter. The master cylinder bolts up to it easily and you can feel the push rod making contact.

One thing that I noticed that concerns me is the right rear seems strange when I try to bleed it. I’m not seeing the volume of fluid out of it that I see from the other three.

I question now if I got a bad component, maybe bad master cylinder, if I have a different issue going on that I do not understand or maybe the wrong components?

Any comments or suggestion are welcome and greatly appreciated. I hate seeing such a nice Jeep sitting in my garage that is useless at this time.

 

[Torxhead]

For starters, you are using a brake bleeder catch bottle with a tube of some sort right?

 

[Frosty72]

You don’t have one of those brake line locks hiding somewhere do you? Sounds like the fluid is staying pressurized after releasing the peddle.

 

[UpHill1]

For starters, you are using a brake bleeder catch bottle with a tube of some sort right?

Absolutely

I use an old brake fluid bottle with a round hole cut in the cap with a 2 ft 1/4 id clear tube. I also have speed bleeders on the front calipers. However with that said I still do it the old fashion way with the wife presing the pedal down when I open the firring, then I close it off, she releases the pedal and we repeat several times each wheel.

 

[UpHill1]

You don’t have one of those brake line locks hiding somewhere do you? Sounds like the fluid is staying pressurized after releasing the peddle.

You read my mind. This has been all I thought about today. Very soft pedal yesterday before I started bleeding again. Now very FIRM. I replaced the front brake hoses for that exact reason. The only other hose is off the tee there at the rear axle. Other than that it is all steel lines.

So I plan to pull the rear hose and check it and most likely replace. Again that right rear wheel just does not seem right when I bleed them. Not a consistent fluid flow like the others.

Thank you

 

[BIG4D]

When the brakes are hot, and not releasing, loosen the master cylinder off the booster and see if the brakes release.
If so, you have either the wrong rod in there or you have a problem with the pedal assembly.


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[cglax6]

When the brakes are hot, and not releasing, loosen the master cylinder off the booster and see if the brakes release.
If so, you have either the wrong rod in there or you have a problem with the pedal assembly.


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Yeah, what he said!

Did you ever figure this out? Sometimes if the master cylinder wasn't designed as a match to your booster (assuming you have one) the pin length may be your problem. If not, you may have an issue with the pedal assembly.

Let us know what you figured out...I just rent through a front disc brake conversion and ran into a few issues along the way, but nothing like what you describe.