Here's my history on brake repair:

-Brake pedal hard to press. Goes to floor. Stopping is difficult.
*Replace Brake Booster
-Master cylinder leaking
*Replace Master Cylinder
*Bleed brakes
-Brake pedal is very soft and travels far before grabbing. Pedal is not hard to use, but exhausting after a while
*bleed brakes
-Problem persists, and also, new master cylinder leaking
*Replace master cylinder
*Bleed brakes
-Brake pedal is very soft and travels far before grabbing. Pedal is not hard to use, but exhausting after a while
*bleed holy hell out of brakes
-Brake pedal seems more normal
(Normal operation for a few weeks, firm brake pedal, adequate travel, good braking)
-Two weeks later:
-Excessive pedal travel to when brakes "catch." slightly spongey pedal feel. Brake catches near floor, will go within 1" of floor when pushed. Hisses LOUDLY when pumped a few times(normal?) Slight pumping improves pedal response slightly, temporarily. Braking distance seems normal. Was sitting on slope in R, facing up, holding the brake, car started rolling backwards suddenly, applieed brake harder
*resolution?? New brake lines?? Another booster??

 

On a station wagon once, I had a similar problem, the pedal would go all the way down, if I stepped on it hard and fast, it wouldn't go down, if I let down on it slowly, it easily went down... turned out to be the booster.

 

I've always thought that if the car rolls while on the brakes, you have a hydraulic leak. Calipers good? Loosing any brake fluid? ABS pump fittings dry? I'm not sure if the ABS pump can leak internally. Hate to say it but is New M/C #2 bad??

Having bad brakes sucks! I had a Sunbird whose booster went out. I had to REALLY STAND on the pedal just to slow down; used both feet to keep it at a stop (auto trans). Pedal was never really mushy tho.

 

Not losing any fluid.

 

:confused:

I've heard that there can be problems with pushrod length. I don't remember exactly what or why. But if the rod on the pedal (or the booster) is too short, it won't press the piston in the M/C all the way. Otherwise, I can't think of anything else.

-Jason.

 

hissing = big vacuum leak. Line broken, or blown booster diaphragm


[Modified by BobMachus, 5:12 PM 11/2/2001]

 

Yeah, if it hisses - it's got a problem. Hard to believe after all those replacements, but sounds like the booster is suspect - again. I would check the elbow where the vacuum line attaches, sometimes they stress and crack, but never seen one that would only 'hiss' when the pedal was depressed.

For brakes, I would only use GM new replacement parts. Never a part from and AutoZone (well maybe NAPA if I was stuck). If these were new GM parts I would raise unholy heck.

After that it sounds like air in the system (I know I said that befoe). But, as many times as the MC has been replaced, that's lots of times to get air in. If air is in the ABS (do you have ABS - forget year) that takes some work and a Tech 1 to get out. If the MC was not blead properly (bench bleeding and fitting cracking, and bleeding with partial pedal depression) it is very difficult to ever get it correct.

Lastly, the flex lines to the calipers, after time and on rare occasions, can collapse under pressure and make for some weird brakes. You can't see the colapse - it happens internally. This is really rare, and does not seem to be the problem. This problem can be hard to discern from brake fade or air in the lines or old fluid. This almost never happens in pairs (like front left and right) and therefore almost always will cause a pull under heavy braking.

Think there is a bad booster and air in the lines. There is an adjustment between the booster and MC that usually can just be set to the existing - however if this is way off, I wonder if it could cause early failure?

Pete

 

yeah, it's a parts store booster. $80 as opposed to $220 + :eek:

 

Sometimes you get what you pay for? I have had luck with parts store stuff, but never buy parts store brake stuff.

Have your tried Jeff Koop or TLD?

After that I would go to a shop with a pressure bleeder and Tech 1 and get the air out!

Pete

 

That's a TLD price. I'd hate to see what GM's price is. I'm just going to get a warranty replacement for $0. The car ain't worth new GM parts unfortunately.
I'll sell it first.. if that was possible. I've ran adds for a few months with 0 response.



[Modified by Smash, 7:18 PM 11/2/2001]

 

OK. But your labor is also money. You could be working OT, or getting an advanced education or cert. that is worth big money, or any number of other personal advancements.

Brakes are your life! What if the next one goes completely without warning? What if it goes when you need it the most? What if if just fails a little, but you have to panic stop - and there is not enough there? No, brakes are worth your life.

I can't stand these SOB's that sell junk rebuild parts. Send them a certified letter that you almost ran over schoolgirl at 15 MPH because of their trash. Put them on warning that you expected a safe part, paid for a safe part, and have had two unsafe parts. Ask them if their parts are safe. Tell them that you feel that you will be responsible for bad judgement in buying their parts and that this letter is Due Diligence in confirmation of the quality of their parts that you have not only paid for, but have invested in labor for both installation and removal. Push them hard for a refund for labor and materials. Tell them you will go public (if you can take the review) if they won't take responsibility for the junk safety parts they are selling.

It's one thing to sell junk alternators, it's another to sell junk that can cause loss of property and life.

OK, I feel better.

Pete

 

you are right about that. I had planned on buying a "metal booster" and new factory MC when I got some GS or C5 brakes, but now I'm wondering if i want to invest any money in this car at all.
I don't know if I can get them to refund the booster. I'm gonna have my bro in-law bleed the holy hell out of the brakes for me (he owns a big-o) and go from there.

 

Whats the tech 1? Is it a brand or type of pressure bleeding system? Is it common in most shops? Thanks

 

Ah-hah
The ( ) part after the T has a vacuum leak around it. Would it be alright to silicone it for now, and replace it when I can? I'm talking about the round "seal" on the booster where the line plugs in

 

Not a good solution, but I've done worse when I was broke. If you take this chance, make sure you clean the surfaces with a good alcohol and allow the RTV to setup for at least 24 hours.

Tech 1 is a scanner tool used by GM techs (also tech II and tech III now), unlike the readily availble home use scanners it allows certain extra functions including commanding the servo's in the ABS unit to open the various valves - which will help with getting out air trapped within the ABS modulator.

 

i opened the "lip" a little and siliconed it, ran it around., I'm gonna let it sit for a few hours, then do a "seal" around the outer edge and let it sit overnight. Should take care of me until I can get a new one from 18carfan, if it's not too expensive.