No fluid to rear brakes 2000 Grand Am

Tiny
ROBERT CRABTREE
  • MEMBER
  • 2000 PONTIAC GRAND AM
  • 3.4L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 80,000 MILES
I changed front brakes and bake pads, rotors, calipers, and all four 10" brake lines that go to calipers. Now im getting brake fluid to the font but not to the backs. I disconnected the brake line (hard lines) from the 10" rubber brake lines to see if fluid would come out of the hard lines, and nothing no fluid at all. I don't see any leaks any were im not losing fluid from master cylinder and there arnt any kinks in the brake lines please help I need to no were to go from here I need car fixed for Monday morning im desperate any info or ideas is greatly wanted and appreciated thanks
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Saturday, August 8th, 2015 AT 3:20 PM

4 Replies

Tiny
CARADIODOC
  • EXPERT
At some point you pressed the brake pedal too far. That must never be done on any car over about a year old. Crud and corrosion build up in the lower halves of the two bores where the pistons don't normally travel in the master cylinder. When the pedal is pressed more than halfway to the floor, either during bleeding, running the pistons out of the calipers, or when surprised by a sudden leak, the pistons ride over that corrosion and the lip seals can get ripped.

You have an additional problem that only involves GM front-wheel-drive cars. If you look closer, you'll see you are indeed getting brake fluid from one rear wheel and only the opposite front one. When the brake pedal is pushed over halfway, a valve in the master cylinder trips to block one front port and the opposite rear one. A lot of people replace the master cylinder for this, then have the same problem.

The only way I've found to solve this is to close three of the bleeder screws, loosen the cap on the reservoir, open the front bleeder screw on the caliper that is not flowing fluid, then give a quick, short burst of compressed air into that bleeder. Let the fluid gravity-bleed, and gravity-bleed the other three wheels.

If you still need to work the pistons out of the calipers, do that by pumping the brake pedal, but never over halfway to the floor.
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Sunday, August 9th, 2015 AT 12:14 AM
Tiny
ROBERT CRABTREE
  • MEMBER
So do I need a new master cylinder because I may have ripped the lip seal or should I just put everything back together cuz I got the back wheels off and I've got the brake lines disconnected to the rears calipers tryin to c if fluid would come out of them but I dont c any from either one but so put everything back together and shoot air into the bleeder screw on the back brake thats not got fluid then start to gravity bleeding the brakes on the back again. Should I shoot air into both calipers on back couse it seems neither is working both rotors r rusty so that tell me neither side is pumping the caliper right
Thanks for your help I need it I will get this fixed with your help don't give up on me lol
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Sunday, August 9th, 2015 AT 6:07 AM
Tiny
ROBERT CRABTREE
  • MEMBER
Ok you're right I was wrong there is fluid coming out of one of the back I didn't realize it till I held my finger on it and I can see then it's such a mInute trickle it's hard to notice thank u so muck I'm going to start your process now I'll give udate
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Sunday, August 9th, 2015 AT 6:42 AM
Tiny
CARADIODOC
  • EXPERT
Sorry for the delay in getting back here. Don't jump on the master cylinder yet. As for which wheel to give a spurt of air, I always have done it to the front one that isn't flowing any fluid. The front calipers are always a lot larger than the rear calipers or wheel cylinders, so there's less chance the compressed air will make it all the way up to the master cylinder. All you're after is enough air to unseat that valve that tripped in the master cylinder. I hold a rubber-tipped air nozzle to the bleeder screw, then give a quick, sharp pop to the lever with the side of my hand. The air only goes perhaps 4 to 6" up the line, and that gravity-bleeds out in less than 15 to 20 seconds.

Funny thing is I just popped a rear brake line today on my minivan. Took me 20 minutes to replace it, then I was able to bleed it right at the joint, and since I had to pump half of the reservoir empty to get home, there was air in the front too. I got that out by filling the reservoir, then pushing the pedal down only halfway very slowly so the air could keep floating back up, then I released the pedal very quickly. The brake fluid rushing back washes the air up and into the reservoir that way. Tonight the pedal is solid again and I can stop whenever I want to!
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Monday, August 10th, 2015 AT 7:51 PM

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