why cant i bleed the rear brakes help

[johnny_boi85]

the other day out of nowhere my rear brakes came on and i had to drive the few K's home with them firmly grabbing the discs i pulled both rear callipers off cleaned them in and out replaced the pads and fitted them back to the the commodore when i went to bleed the back brakes nothing happens when i open the bleeder no fluid comes out and the peddle dosnt move i checked the rear brake lines with a air hose to see if the line was blocked but that was ok the i tryed to bleed the front brake and i didnt have a problem with them at all i could replace the calipers but is it likley that both rear calipers stuffed up at the same time or could it be the master cylinder even no i can bleed the front brake fine ? ? ? ? ? ? ? ? ?

[w1war3na]

it could be just the brake lines have alot of air in them try pumping more fluid into them one at a time, but keep a close eye on the fluid level

[johnny_boi85]

tryed that me and a mate sat there for about an hour he would pump the brake peddle then when he held the brake peddle down i would open the bleeder but nothing would happen no air or fluid would come out and the peddle wouldnt sink to the ground like it should we tryed the same procedure with the car on and off to c if it made a differnce because of the brake booster but no its the same for both rear brakes. but the front bleed normal could the master cylinder only push fluid to the front brakes and not the rear i just cant figure it out and i dont have the funds atm to go buying something i dont need

[TheIceman]

mastercylinder maybe. do you have a good high feeling solid brake pedal or low and spongy?

[pablo]

Do you have an ABS brake system?

[moose man]

You say you have done nothing to the car recently? Unusual. Ok...

Make sure the brake pedal is returning all the way to the up position. Check there are no wires, plastic trims or carpet stopping the pedal movement back to fully up.

If this doesn't work, use low pressure compressed air in one rear brake hose to (carefully) push air back up the brake line. Don't do this too hard or the fuid will spray all over the engine bay. This will tell you if there's a blockage in the line, or if the line's pinched/bent. Fluid or bubbles should come back out the master cyliner reservoir.

If this doesn't work, you need to crack each connector one at a time from front to back and try the air thing each time until you get air flow. This will isolate the line/component with the blockage.

[Tree cutter]

I would put my money on it being a broken spring in the master cylinder. The front and rear brakes operate off a separate piston in the same bore of the master cylinder. There should be a spring between them and a spring in front of the front piston. I would say that either the spring betwwen the two pistons has rusted or broken or the rear piston has jammed in the bore so it is not returning to where it should be when the brakes are released

[johnny_boi85]

ok to (theiceman) atm the brakes are spongey but thats because i cant get the air out of the line. second (moose man) when i say i havnt done anything to my car i mean i have never touched the brakes beside putting new pads in when i got the car and filling up brake fluid i checked to see if there was and wires or carpet or stuff stuck behind the brake pedal but theres nothing but like i said when i bleed the front brakes the padal returns all the way up and after pumping the brake when i hold the pedal down and my mate cracks the bleeder the pedal goes to the floor so i no its not the pedal if it does that for the front brakes i will try you idea with the air but thanks for that. Thirdly (Tree cutter) is there a easy way to test if it is the spring at all or do i have to pull the whole thing out or is it in my best intrests just to buy a new master cylinder thank guys for all the info it is helping

[johnny_boi85]

na dude no ABS just total standed brakes