The car has been sitting a little while, the brakes seemed ok last time I parked it but I never was very happy with the holding ability after the brake job I did. I replaced the rotors and pads. I just checked the clearance for the e brake, seemed ok. Fluid level is fine, no apparent leaks. Brakes are not glazed or rusty, so thats not it... maybe dusty more than anything and I found a spider web... maybe thats it lol. Anyway, moved the car and heard a funny noise and I thought it was the rear tires slipping or something and moved the car back and forth a few times and the observer outside the car said the rear tires were spinning. Not good... well, maybe for doing burnouts at the dragstrip but there's no linelock on the car.

Any ideas? 69k on the odo, car is an 89. Rear hoses look like... 89. Thought about replacing them just in case. Didnt see any cracks or sign of cracks in the hoses though. I had bled the system when I did the pads and rotors so there shouldnt be any air in there... but it sorta acts like it.

 

Yeah. 18 years old. The hoses are cheap. Replace them and then re-bleed. Brakes are the one part of a car that can't be just "almost" right.

 

Also, the PBR rear calipers are prone to getting gummed-up where the pin goes into the main piston. You may want to rebuild the rear calipers, it's relatively easy to do.

 

I might do that. Going to try to bleed the brakes tonight, see if that does any good at all... probably not, but hey... I'll give it a shot. If not, hoses and caliper kit here I come.

 

Well, that didnt work.
Doesnt seem to me like there's enough fluid moving through the bleeder... but thats just a guess. Initial impression says there isnt much going on at the master, either. Possible the master is shot? Guess I'm gonna find out...

 

I replaced the master on my iroc once, thinking it might help out. The reality of it was that it did little. Don't get a cast iron one either, they rust overnight. Try to find an aluminum replacement if possible. I rebuilt my rears, put earls ss lines on them, fresh hawks pads, and they felt "better," but I still feel like they can do more. I haven't driven the car in over a year now, but I am putting c4 brakes on in the spring, and when I do that, I will probably blow the lines out and start over with a rebuilt stock master, new prop valve, and see how that works.

Hope you get her straightened out.

 

Did you rebuild the calipers? If you are barely getting any fluid through while bleeding your probably right about a dead master cylinder. I used a new Bendix master from a '98 Z28 (mostly for the reservior) and a 1LE prop-valve, which do wear out as well. They bolt right-up (using the proper prop thread) and work very well together.

 

Nah, havent gotten to it yet. Fortunately, this car isnt a daily driver. Unfortunately, its not much more than a garage ornament right now. I did move it yesterday just to get fluids moving and with the e-brake on I can stop the car but the feel is... terrible.
I plan to try the rebuild kit first, then go from there. I have a feeling though rebuilding calipers isnt going to fix my problem.

 

Ok, I just read all of what the poster posted but heres some things you can try.

1. Master Cylinder might be shot. Just because it dosent leak fluid dosent mean that your primary or secondary cups arent blown. Your Compensating and inlet ports might also be clogged. So check the master cylinder.

2. Might want to check your Proportioning valve.

3. Replace rear lines, yet again just because they arent leaking dosent mean they arent clogged.

Also keep in mind that the rear brakes only do 25% of the braking. So you might want to check your front brakes to.

 

I can check the front, but stopping the car hasnt been an issue... stopping the rear tires is.

I'm not sure about the master myself. Seems like the fluid movement that is visible for the fronts is normal and the rears is non-existant. Its either blowing by the internal seal or there's some sort of blockage to fluid movement between there and the brake pads. The e-brake effectiveness (not so good) has me leaning towards fixing up the calipers first.

 

While not a true diagnostic technique, this simple trick can help to determine if it's time for a new master cylinder... Open the reservior cap, stick in your index finger and drag it about an inch across the bottom, pull it out and observe - if you have a glob of black slime on your fingertip, that's seal material that has broken down from fluid saturation, heat, use, and age. Time to replace....

 

That can all be cleaned out, then flush the system.
My 86 daily driver has 218k on its original master cylinder.

 

It's well overdue and a brand-name new one is so inexpensive it's not worth chancing catastrophic failure that could cost you your car, or worse! Are you really willing to chance your safety and your car to thin, tiny 20 year old rubber o-rings and seals that have been pressure cycled over 20,000,000 times, heat cycled nearly every day for over 20 years, and already showing evidence that they are breaking down?!

 

There isn't a darn thing wrong with that MC. If we take your theory that just because of age you replace something then you better get busy because you have a lot of parts to replace. Never had a brake failure in my life course I do all my own work.

I have three 20 + year old vehicles with the original MC.
It's called regular maintenance. Changing out a perfectly good MC is not on ANYBODYS regular maintenance schedule. Go ask a dealer. Flushing the system with new fluid is on SOME maintenance schedules for sure. That's all that needs to be done.

 

Well I should be able to answer the question (I hope) sometime before Xmas. There was some black residue, and given that its a sealed system and I dont know of any particulate matter in the brake fluid that turns black... rubber fragments is the most likely explanation. I also have an 86 and it has the original master cylinder with 160k miles on it and its just fine. It would be disappointing if the newer and much less mileage one on the 89 was done but given that parts fail when they feel like it, its possible.

 

Using your theory the bald, dry-rotted rubber rings around your wheels are doing just fine too! I guess that the rubber bushings in your suspension and the seals in your drivetrain last indefinitely as well? I mearly offered you advise based on years of working on brakes and suspensions professionally, take it as you will. There is a lot of room between brand-new and catastrophic failure and I will always err on the side of caution, particularly with the #1 safety system on my vehicle. 100K miles is about all I would ever trust any brake system components, and the dealer is the LAST person I would ask advise from in dealing with a 15+ year-old car!
That's enough hijacking, back to the topic...

 

How old are you ? My experience speaks for itself with these matters.

You don't fix what ain't broken unless it is an upgrade. You are wasting your money and NO ONE here is going to agree with you.

 

Better change your battery, starter, alternator and water pump and etc, etc and etc..........and that pesky air pump and power steering pump that has been on there all them years.

Darn thing has to be bad....LOL

 

Like Murco said, back to topic.

JamesC