No fluid to rear brakes

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 I am 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 do not see any leaks any where I am not losing fluid from master cylinder and there are not any kinks in the brake lines. Please help! I need to no where to go from here. I need car fixed for Monday morning. I am desperate any information or ideas is greatly wanted and appreciated. Thanks.
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Saturday, August 8th, 2015 AT 3:20 PM

6 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 do not 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 will 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 have 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 because I got the back wheels off and I have got the brake lines disconnected to the rears calipers trying to see if fluid would come out of them, but I do not see any from either one. So I put everything back together and shoot air into the bleeder screw on the back brake that is not got fluid then start to gravity bleeding the brakes on the back again. Should I shoot air into both calipers on back?Because it seems neither is working, both rotors are rusty so that tells me neither side is pumping the caliper, right?
Thanks for your help. I need it, I will get this fixed with your help. Do not give up on me, lol.
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Sunday, August 9th, 2015 AT 6:07 AM
Tiny
ROBERT CRABTREE
  • MEMBER
Okay, you were right I was wrong, there is fluid coming out of one of the back I did not realize it until I held my finger on it and I can see it then. It is such a minuscule trickle it is hard to notice. Thank you so much. I am going to start your process now. I will post an update.
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Sunday, August 9th, 2015 AT 6:42 AM
Tiny
CARADIODOC
  • EXPERT
Sorry for the delay in getting back here. Do not 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 is not flowing any fluid. The front calipers are always a lot larger than the rear calipers or wheel cylinders, so there is less chance the compressed air will make it all the way up to the master cylinder. All you are 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 fifteen to twenty seconds.

Funny thing is I just popped a rear brake line today on my minivan. Took me twenty 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
Tiny
MITCHELL FOSTER
  • MEMBER
Hi, I have a 2000 Pontiac Grand Am 3.4 L. I replaced my front brake pads and when I went to bleed my brakes I noticed that no air or fluid was reaching my rear brakes. My brake lines appear to be relatively new. I noticed that is the brake lines run into a distribution box that connects to the master cylinder. I already replaced the master cylinder so I know that is not the issue. Could the box that connects the brake lines to the master cylinder need to be replaced?
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Thursday, June 21st, 2018 AT 9:18 AM
Tiny
CARADIODOC
  • EXPERT
If that box you are referring to is bolted right to the master cylinder, that is the hydraulic controller for anti-lock brakes. I never ran into this problem on a GM front-wheel-drive car with anti-lock brakes, but the same solution applies. I would try the compressed air procedure at one of the wheels where no brake fluid is flowing. If that does not work, you may need a scanner to send the valves "home" in the hydraulic controller. This ABS system is very inexpensive and quite effective. The three valves should home automatically, but nothing will happen unless the ignition switch is turned on.
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Thursday, June 21st, 2018 AT 7:05 PM

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