bobabooie

iTrader: (7)

So last April I installed a set of used stainless steel brake lines on my 01 SS with 29k on it whle changing out the warped original rotors and of course got air in the system. I tried to bleed the air but figured out that I had air in the ABS as well. The pedal would pump up to the top as long ad the engine was off but as soon ad it starts, it went to the floor and barely stops. After some research and thought, I figured it would be best to take it to the Chevy stealership to have it done right. They bled the car 3 times and wound up telling me that the pedal goes to the floor because the master is bad. Giving me a bs excuse that since the car sat most of it's life that the seals must have rotten out and blew out during the bleeding process. They quoted me $1200 for a new one installed. I of course changed it myself even though I doubted their diagnosis. And after doing it, I still have no brakes and still get ZERO air while bleeding. A GM tech told me that it sounds like there is still in it or that the booster must have crapped out and to test it by slamming the brakes at idle to see if it pulls the RPM's down which it does. I have been so frustrated that I don't want to mess with it but it would be great to figure this thing out. Besides power bleeding the brakes, I am at a loss. Does anyone have any suggestions?? Or have a bleeder and are somewhat local? I reused the original calipers, just changed the lines. It pumps up and it VERY firm till you start the engine, then it goes to the floor. I would have it done but I don't know of anyone around here who can actually get it right.

bobabooie

iTrader: (7)

Sorry for the long post. The used lines were from a friends car that he was selling, so he pulled them off but they worked fine before. Should I pull them off and install a new set? The rubber originals? Or any other ideas?

Grimes

iTrader: (3)

I mean, i think you really should just keep bleeding the system. Are you starting with the rear passenger wheel, then rear drivers, then front passenger, then front drivers? There has to be air in the system. I mean, you have replaced the master cylinder too, so that eliminates that source of trouble.

There is a small shot that you got a faulty master cylinder, but that would probably be extremely rare.

bobabooie

iTrader: (7)

Grimes, that is the order I have been bleeding them in. I have run 2 if the large bottles of fluid through it and the most I have gotten out the last 3 times was about 5 air bubbles the size of pin heads out of the back passenger side. So all in all I have bled it 10 times and the dealership did it 3. Does the key need to be on while doing it to open up the ABS module? It't like the air is trapped somewhere.

Grimes

iTrader: (3)

Well, personally I have swapped out an abs module on a GM car, and then bled normally with no tech2 and it worked out fine. But technically the correct way is to cycle the ABS module. The dealer should have done it the "correct" way.

Honestly, if you just put in a new master cylinder, there probably was a warranty on it. You can try bringing it back for exchange. Then you could be 100% certain it was not faulty. I'm just saying this because it looks like you have the bleeding done correctly by yourself and the dealership.....

You could try the power bleeding, but all my life I have done the regular two person manual bleed, and it has worked fine every time.

bobabooie

iTrader: (7)

When I was getting upset with the whole ordeal before taking it to the dealership, I forced the pedal down and it honestly felt like something gave out at the bottom of the travel. Could I have damaged the booster?

Grimes

iTrader: (3)

I think if you damaged the booster, you would get mostly a hard pedal, because you would not have the vacuum assist helping you out, you know? I dont think it would just get softer.

bobabooie

iTrader: (7)

True. Never thought of it that way. The mechanic that I spoke to has a tech II scan tool and pulsed the ABS for me but still nothing came out. But he thinks it's air as well. Just trying to figure out if there is a better way or if I'm missing something in the process.

Also the car has gone 30 miles in two years, sits in a garage and has not lost a single drop of fluid. So I have ruled out a leak.

1 FMF

iTrader: (1)

if you put a new brake master cylinder in, did you bench bleed it? when bench bleeding it you pretty much can tell if it's bad because it won't hydraulic lock and the plunger will go down after 10 seconds. if you didn't bench bleed it, then you have a lot of air in the system. my recommendation is bite the bullet and buy a motive power bleeder and cap for $100 and power bleed it. otherwise the other thing is to get some earl's solo-bleeds for the calipers so you can just pump the brake pedal like mad and push air out of the system. most people overlook or don't realize what's happening and what needs to happen, you need to force air through the brake lines and out the calipers, all of which is downhill (master is higher than the calipers, air bubbles up. so if you are pumping the brake pedal once while someone opens then closed the bleeder, you are not moving enough fluid fast enough for a long enough duration to push air downward through the system. so, power bleeder. and if you get the motive power bleeder i recommend you use it as just an air tank to pump air into the master thats full of brake fluid, just never pump the master down so that air gets into the cylinder. the motive caps are notorious for not sealing and making a mess.

bobabooie

iTrader: (7)

I bench bled the master before installing it. I have heard if the mityvac unit but not the motive. Time to do some research and see where I can get one. I figure it will pay for itself with not having to buy 12 packs of beer to recruit a helper. I have been wanting to do the F-body brake upgrade on my GTP but since the brakes are similar, I have been waiting to figure this one out first.

bobabooie

iTrader: (7)

Picked up a Motive bleeder this afternoon at Jegs. Hoping this works.

Grimes

iTrader: (3)

Good luck, keep us updated

1981TA

iTrader: (7)

This may sound goofy, but also have someone visually watch your brakes and lines at each corner while you hit the brakes. This will require the wheels to be off, and the car properly placed on jack stands or a lift. See if anything weird happens (like a line ballooning, or a caliper visibly moving), and fix appropriately. Also...

1. Are your pads glazed? I did that to my wife's van. That was one scary car to stop.
2. are your pads worn evenly?
3. Is there oil, grease or brake fluid on your rotor surfaces?
4. Are your pads worn equally on each side of a given caliper (might be a sign that your caliper slide pins that need lubed)

Cool28

iTrader: (2)

I used a cheap cap with a air hose hookup to bleed my brakes. I replace all the lines including steel. Didn't have a problem. The cap was way less then 100 bucks to.

bobabooie

iTrader: (7)

So an update. Finally got around to bleeding today. I ran 6 32oz containers of fluid through it with the motive bleeder. And no change. The car still stops the same. When applying the brakes, the car will start slowing down as soon as I touch the pedal and will hold on a hill, but if I apply any kind of pressure or keep pushing the pedal it still goes to the floor. So I know it is something in the hydraulics as the pads and rotors do their job and are clean. But it still acts as if there is air somewhere. I am at a loss with this issue and hate to give up but it seems that nothing is helping. Anyone have any other suggestions?

bobabooie

iTrader: (7)

So I talked a GM master tech into bringing his tech 2 over and running another brake bleed. We only got a handful of bubbles out and it did nothing to help the pedal. So about the only thing left is the booster. I'll update if that solves it.

Alex L.

iTrader: (16)

Disconnect the booster and try braking at SLOW speeds to see the results. Just a thought.

1 FMF

iTrader: (1)

the booster would not cause pedal to the floor. if pedal to the floor does not happen under your own leg strength with engine off and no booster assist, but it does with engine running then that means the booster is working.
for the pedal to go to the floor then one or more of the following is happening:
- linkage between pedal and master cylinder broken or bent and that is giving so your pedal is going to the floor but it's not translating into fully depressing the master cylinder to move brake fluid.
- the master cylinder is faulty and under booster assist the seals are giving and the plunger is moving without moving fluid
- there is a leak in the system and everything is working but when master cylinder builds pressure brake fluid is escaping somewhere allowing pedal to the floor.
- there is still air in the system, but with engine off if you can pump up the pedal and the pedal does not depress far and hardens up and you cannot push it farther with 100 lbs of leg strength and it holds then i doubt there is air in the system.

regarding #1 and #2 a way to find that out is to get plugs for the master cylinder output ports. disconnect the lines from there to the abs module and plug the master cylinder. then engine running depress brake pedal and if it still goes to floor with no fluid leakage then it's either faulty master or bad linkage between it and your brake pedal. if you get plugs you need brass or steel plugs for a bubble flare fitting so it seals, and be careful you don't make a mess. if plugs aren't available, get a piece of brake line with jap metric fittings and bend it 180° to connect to both ports of the master.