Hey all,
I have a 97 z28 M6 rear end is on jacks, car is turned off. Just finished installing ss brake lines due to mushy brakes. I ran into issues when trying to bleed the system starting at the front 2 abs fittings then moving to pass rear. When helper was pumping the brakes I could hear air escaping from somewhere. Found it to be coming from the intake hose. Didn't think this was normal so I disconnected the brake booster vacuum hose going to the intake and capped it off using a bolt. After capping it I had helper start pumping the brakes again and I heard air still escaping. This time I found it coming out from where the MC connects to the BB. Then disconnected the MC from the BB since I thought it was leaking fluid from the rear (I’m thinking the cap). I used a 3/8 ext to push the piston in. MC didn’t leak air or fluid.

Are these normal indications?

I figured there was a problem since it was taking forever to get any fluid to come out of the pass rear. And while pumping the brakes they never seemed to get harder to push.

I’m trying to bleed the brakes by pumping the brakes to build up pressure then open the respective fitting. I would continue to do this till all air bubbles are gone and the fluid is clear.

To finish it off while the MC was off I pushed the brake pedal in and something fell off or got sucked inside. And i can't find it anywhere. I feel like a total noob right now.

Could I have a bad brake booster?

Any help will be greatly appreciated!

 

I don't think this is your whole problem but the sequence is left front, right rear, right front, left rear.

If you let the ABS module run dry, you may need a tech I (GM Tool) to re-set it.

 

This air escaping while apply the brake pedal is a bad brake booster diaphragm. Maybe you will find brake fluid into the brake booster.

The vacuum hose (are broken?) must be firmly attached to the source in the intake manifold and the check valve too. Clean and lube the grommet and the connectors barbs.

You have to purge the ABS module first then each calipers as JohnD described it so. But you have to rehome the ABS module pistons in very first palce either TECH 2 scanner (preferred method) or manually. Should not be any ABS DTC present, such is, the amber ABS warning light must be OFF all times before 3 secs you start the ignition switch.
Manually:
Don't touch the brake pedal
Start engine and allow it to run for almost 10 seconds. Observe the amber ABS warning lamp
If the amber warning lamp turned ON and stayed ON after 10 secs You need to conect the TECH 2 scannner and STOP flushing procedure. Prepare your green skinnny leaves to fly at the GM dealer.
If the amber ABS warning lamp turned ON for 3 secs and turned OFF and stayed OFF then turn off the engine.
Pepeat procedure one more time
You're redy to flush or bleeding the brake fluid in the system.

Puff....at last..

Hope this helps

dochidalgo

 

I thought after bleeding the abs you move to the furthest caliper from MC?

 

ohhhh, my mistake, yes:

ABS module, RR, LF RF LR

My apologies

dochidalgo

 

I used a Mityvac vacuum pump to bleed the brakes, then swapped out BB. Everything works now. Brakes feel better than before but still don't compared to wife's altima. Thanks for all the help!

Do LT1 brakes just suck?

 

The sequence at the wheels is RR, LR, RF, LF.

 

Thanks

 

Thanks, shoebox, I thought I was losing my mind (well, I still might be) reading these responses. I always started with the longest line, being the RR, and working backwards to the shortest line.
From an Internet source:
"When you are bleeding the system, start with the wheel that is farthest away from the master cylinder, and then work your way back towards the front left wheel. In other words bleed the system in this order: right-rear, left-rear, right-front, left-front. Bleeding in this order will minimize the amount of air that gets into the system. Always bleed each caliper more than once, because bleeding the other calipers can dislodge air into the system. You might be surprised that after 5 times around the car there still might be a little bit of air in the system. A good rule of thumb is the more you bleed, the better your brakes will be."
If you use a Mityvac, be aware that you may get some bubbles. This is caused by the fact that the tube itself is not completely sealed on the nipple (unless you clamp it, which they don't mention). So don't let it worry you, just go with the flow. So to speak.

 

I was puzzeled reading it myself. So much that I looked it up in the manual to make sure I had not suddenly gone crazy.

 

I´ve read the GM 1997 Service Manual (GMP/97-F-1) Book 1 of 2 F Platform
page 5-31 Brakes Manual Bleeding Procedure Point 9 Bleed sequence

and it stated there the sequence I wrote. I want to be sure about it

Clarification only

Regards
dochidalgo

 

Forgive my ignorance, but I'm on my first Camaro, in fact, first-ever GM product. I have a '96 Z28 with ABS and ASR. I'm trying to figure out why I need to bleed the ABS unit, if I'm only going to be replacing the calipers while the respective brake lines will be clamped. How much air can possibly get in the system this way, especially enough to travel all the way to the ABS module? Or am I missing something here? I will NOT be replacing any brake lines.

 

A properly working brake system is a sealed system other than the fill cap so you shouldn't have to clamp any lines other than the one you are working on. Personally I would just make sure you can get the brake line off the old caliper before removing it- keep it tight enough to prevent air from entering. Mount the new caliper and transfer the line to the new caliper.

On a side note- I bought the $5 bottle from Autozone for bleeding brakes and I must say it worked great. When I swapped over to SS lines on the car I was able to bleed all 4 calipers by myself. I'm sure there are better systems out there but for the $5 it was worth it.

 

That's what I was thinking too, but there seems to be a lot of adamance out there on the subject of bleeding the ABS unit. Just seemed an awful long way for the air to travel.