rebuild or replace?

[Tom]

Well, Ive bleed my brakes 11 times now, getting bubbles in the back every time. Ive replaced both front brake lines, and replaced all the brake fluid. The front left caliper has been replaced. Still the brakes arent working correctly.

Im not sure what the heck is going on. One thing: the left rear brake didnt push much [if any] fluid out the last time I bleed it. Im going to see if its clogged somewhere, and if not then Im guessing my only choice left is to replaced the master cylender. Should I rebuild it, or buy a rebuilt one from NAPA?

[79Silv4x4]

NAPA

[low 84]

i would just replace with a napa. more trouble than its worth to rebuild it IMO. i've had them apart and they are a pita to mess with.

[PHOENIX]

I have the lifetime warranty mast cycl. from autozone. It works ok, but after about a year to a year in a half it starts leaking. Usually a gasket or something. Other then that it just keeps going. Im gonna replace this one for free, but after that I think I might go new GM. What do you guys think about new GM master cycl? Tom I say replace it, dont waste your time on it. Napa is supposed to have the best rebuilts around, out of the stores. I have had a few friends who have gotten them and not had any problems, couple years nows.

[Tom]

Before I run out and buy this master cylender, can you guys think of anything else Im missing?
When driving, my brake light stays on. I dont get any brakes until Im at least half way threw the pedal travel, then it starts. It feels like Im only getting half my brakes, whether it be just the fronts, just the rears, or a little of all. If I pump the brakes, the light stays on until I release the pedal, then for a split second it goes out. Every time I bleed the brakes, I get more air out the back. There are no splits in the lines, no fluid leaking out anywhere.

[PHOENIX]

You dont have any leaks in the system anywhere do you? Check everything very very well. Follow each line and feel them with your hand to make sure none are leaking. One single little leak can cause many problems in your brake system.

[CustomChevy]

power brakes or manual?

checked your booster? (if power)
make sure vacuum is good.
also, try braking with engine off. see if it brakes the same way.


if bubbles in line, work out each line again. check for leakage.

hope this helps,
good luck!!!

[Tom]

thanks for the help guys. Its power brakes. Vaccum to them is good. The only problem I had before I dis-connected the rear lines for the flip kit is every once in a great while the brakes would get spongy and the pedal would travel a ways down before it would brake. Releasing the pedal and pushing again always solved the problem. Since it only happens about once a month, I didnt worry about it.

[Bowed]

Originally posted by Tom
I dis-connected the rear lines for the flip kit.

I was trying to remember my basics on brake systems and was thinking , if you loose a lot of fluid from one half of the system don't you have to " ALSO " bleed the porportioning valve to make the whole system work right .

[solidaxel]

Bleed the prop. valve this should center the piston in the valve, you will know it when the light goes off. do this last after you have bleed all four corners!!

[J-Spec C10]

I don't want to hijack Tom's post, but how do you bleed the Proportioning valve? would it cause the rears to lock up under light braking if it was bad?

[solidaxel]

With foot pressure on the brake peddel crack the nut on the front lines and then the rear lines. There is a piston that moves in the direction of the fulid loss to stop the flow of brake fulid, and this in turn makes contact with the wire connection on top of the prop. valve and turns on the light in the dash, I beleive that is how it all works. It did for me when I put one on my 55 GMC.