Brakes STILL spongy
08-20-2009, 07:08 PM
#1
Brakes STILL spongy Ok, this is a long post, but I figure the more info, the better. This is on my 97 Trans Am.
I've had a rear and squeak for a while, so I took some known good rear calipers off my junk Camaro and put them on my T/A. For fluid I used Valvoline Synthetic.
To bleed them, I bought 4 of those Earl's solo-bleeder screws. Well, they didn't work so well. So I bought a Motive power bleeder and put the OEM bleeders back on. So far, that thing worked pretty well.
But here's my problem. I've flushed the whole system 3 times, and the brake pedal is STILL spongy! I'm about to lose my mind. I've pumped over 5 liters of fluid through this thing, bled the ABS block, bled the wheels from farthest from the MC to the closest, and in reverse order.
I got a whole lot of air out, and the pedal feels nice and firm. Until you turn the engine on. One press and the pedal goes almost to the floor until it starts getting harder. If I turn the ignition off and pump the pedal a little, firmness comes right back. And once the engine is on, same thing, the pedal just goes almost to the floor. I rolled the car back and forward a little, and the brakes do catch and hold. It's just the pedal is spongy as hell.
What the hell am I doing wrong? My first thought was that I f'd up the master cylinder. And of course my second thought is that there is still a lot of air in the lines. But I'm stumped, and I want my car back.
If anyone has had a similar experience, please chime in. Or if you have a better way of bleeding these PITA brakes. I need to get this done, it's my DD. I'm so close to just taking it to the shop and letting them fix it.
Thanks in advance.
I've had a rear and squeak for a while, so I took some known good rear calipers off my junk Camaro and put them on my T/A. For fluid I used Valvoline Synthetic.
To bleed them, I bought 4 of those Earl's solo-bleeder screws. Well, they didn't work so well. So I bought a Motive power bleeder and put the OEM bleeders back on. So far, that thing worked pretty well.
But here's my problem. I've flushed the whole system 3 times, and the brake pedal is STILL spongy! I'm about to lose my mind. I've pumped over 5 liters of fluid through this thing, bled the ABS block, bled the wheels from farthest from the MC to the closest, and in reverse order.
I got a whole lot of air out, and the pedal feels nice and firm. Until you turn the engine on. One press and the pedal goes almost to the floor until it starts getting harder. If I turn the ignition off and pump the pedal a little, firmness comes right back. And once the engine is on, same thing, the pedal just goes almost to the floor. I rolled the car back and forward a little, and the brakes do catch and hold. It's just the pedal is spongy as hell.
What the hell am I doing wrong? My first thought was that I f'd up the master cylinder. And of course my second thought is that there is still a lot of air in the lines. But I'm stumped, and I want my car back.
If anyone has had a similar experience, please chime in. Or if you have a better way of bleeding these PITA brakes. I need to get this done, it's my DD. I'm so close to just taking it to the shop and letting them fix it.
Thanks in advance. 
08-22-2009, 01:31 AM
#6
Ok, a little update. I didn't get a chance to work on it today, but I did check how the brakes responded (mostly trying to see if the pedal bled down, which would point to a bad MC).
I can pump up pressure with the engine off, and it holds. With the engine on, the pedal always feels the same. I held the pedal hard, in neutral, drive, and reverse. All the same, the pedal did not move. It goes down quite a ways, but it grabs before it bottoms out and holds there.
So I'm guessing I still have air in the lines somewhere, and that hopefully my master cylinder is OK. I'll try bleeding them again tomorrow. If anyone has any other input, I'm all ears. Thanks!
I can pump up pressure with the engine off, and it holds. With the engine on, the pedal always feels the same. I held the pedal hard, in neutral, drive, and reverse. All the same, the pedal did not move. It goes down quite a ways, but it grabs before it bottoms out and holds there.
So I'm guessing I still have air in the lines somewhere, and that hopefully my master cylinder is OK. I'll try bleeding them again tomorrow. If anyone has any other input, I'm all ears. Thanks!
08-22-2009, 12:15 PM
#7
Is it possible that a little bit of air is trapped in the calipers? I was told to tap the caliper after bleeding that wheel to dislodge air, then repeat with the others. If ALL the air is out (no bubbles) , could air be coming IN from a loose fitting, corroded line?
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08-23-2009, 08:15 PM
#8
FINALLY! I got all the air out, and the brakes feel good and strong again. I even checked my brother's Camaro to see if the pedals felt the same, and they did. I just ended up power bleeding them some more, and found a lot more air trapped in a couple lines. Thanks for all the help guys!
And thanks for the tip, it helped get some more of the air out.
And thanks for the tip, it helped get some more of the air out.
