Hi all,

I have an interesting break issue.

About a month ago the breaks where fading and needed to be pumped. I figured the rear wheel cylinders where gone.

Opened up the rear and looked like one of the cylinder sides had seized completely and the other only one side was seized.

Went to Napa and got a replacement pair, and I have a homemade topsider and vaccumed in new fluid.

Breaks where back to awesome! Then soon after that it was going back to not having a full pedal. Sometimes it'* almost there, sometimes I have to stomp to break.

Anybody run into this?

94 bonneville SE.

Thanks!

Have you ever replaced the rubber lines? It'* possible one is letting go and expanding. I'd pull the wheels and have someone take a look while holding the pedal.

Talking about the front?

I'll have a look at it over the weekened, but the last time it happened (bad rubber) my truck would dive bomb to the opposite side of the bad rubber.

Merely tossing out a suggestion.

Either that or you didn't get all the air out.

Bill'* 2 suggestions are the most likely culprits, but you may also have a master cylinder issue. When you have a full pedal, does it drop down when you hold constant pressure on it for a few minutes?

My money is on air in the lines.

Bill,

Not trying to "Poo-Poo" your idea, and I REALLY appriciate your feedback, just trying to figure out the logic, and I know how hard these things are to diagnose over the wire...

As for air in the lines, which is what I'm thinking as well, I never let the reservoir get empty, and I had a SOLID pedal after I bled it, and after a few days it was back to mush. Does that sound like air in the system?

also, sometimes I have a full pedal and sometimes I don't. It'* very inconsistant. Sometimes I'm driving for a while and It'* there and sometimes it'* not, others, I use it full and a few seconds it'* gone...

2K,

When you say a full pedal, engine running? pump and hold? If & when I get a full pedal?

Thanks again...

Engine running, pump until solid and hold for a minute or so. If the brake pedal slowly moves down you probably have a master cylinder issue. If it holds firm, it is something else.

With your rear brakes in such inoperable condition previously, I have a couple of theorys. Once you get the brakes up, is the pedal nice and firm, or is it spongey? I wonder if the adjustors are seized, and the brakes are not adjusting properly now. Very possible since they were not moving for so long. I would pull the drums again, and make sure everything is still in good shape, the adjustors turn free, and the gear teeth are not worn down.

Depending on how old the adjustors are, you may just want to replace them to be safe. It'* cheap insurance.

I'm with you on what you are saying. The two items I suggested first are based on the work that was done and the resulting issues that typically happen. No sweat ...I'm typically sitting here smiling as I type stuff like that. Been there, looked for answers and found that usually it'* go figure it out.

I'd agree it could be the master with some of the additional stuff you mentioned. The pedal should be consistent, even with a bad line ballooning. When it'* not consistent, that'* commonly a master seal starting to go and acting funny.

When I replaced the wheel cylinders I adjusted the adjuster and I only have 2-3 clicks for the parkign break...


Ok, 2K, I tried what you said and pumping for a minute, engine running led to no increase in preasure. it holds but at the bottom 1/4 pedal and pumping only brings it up to the bottom 1/4.

Not very consistantly, but I noticed if I'm driving for a while and press on the breaks I get a fuller peddal (about 3/4) . If I press it again in under a second, I get a low pedal (about 1/4).

Taking a shot in the dark here, but if I have a small vacuum leak in the booster would it cause this?

Also at one intersection I put my foot on the break and I had a decent pedal, took a little pressure off and pressed again and it went pretty low.