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91 J body brakes

  
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91 J body brakes

 
netwarrior36 netwarrior36
User | Posts: 100 | Joined: 10/08
Posted: 05/01/13
06:05 PM

On my 91 sunbird I've recently replaced the brakes, pads and shoes. Shortly after replacing my brakes a wheel cylinder went out, ok no big deal there. After replacing my wheel cylinder I attempted to bleed my brakes but I wasn't having much luck, issues with getting the system pressurized. Being that I couldn't get the system pressurized enough to push anything out I started my car let the boost build back up then I.was getting great pressure so I finished bleeding. After I bled the system I started my car again and the pedal went to the floor, I could hear quite loudly, my booster sucking air and it was killing my car. Once I finally got it to idle without dying the hissing stopped but my brakes had no pedal pressure though they do work when pedal is push to the floor. When I'm applying my brakes the engine shutters, a his can be heard when applying the pedal. My master cylinder res is staying full, there are no leaks but still feels like its full of air after bleeding. Is my master cylinder shot, is it a bad booster or check valve? I'm at a loss and with as much as I've put into this thing my wallet is running thin so I don't wanna replace something that's good. Also on the side, does anyone have a vacuum diagram of the engine compartment for a 2.0 k code engine? Thank you.  
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"If it breaks it was good, and if it doesn't break it's bad."

1978 Chevrolet Nova two-door hatchback

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 05/02/13
09:29 AM

sounds like you have multiple problems..

the booster is probably damaged from full stroking it..  and will need to be replaced..


the master is probably damaged as it was also full stroked where it had lived with only partial strokes for decades and once full stroked thru corrosion .. the soft seal faces were scratched... preventing a proper seal against the bore... so the pedal goes to the floor...

please also invest in a hand pump type brake bleeder... they work great...

or .. you can sometimes gravity bleed the system one wheel at a time...
but when you get the air out.. use a hand.. and bump the brake pedal.. rapidly.. but only about half an inch.. just enough to build pressure.. but not enough to cover the fill ports... this builds pressure to push the fluid thru but not any vacuum to pull air back into the system..   think machine gun.. spitting out little pulses of brake fluid..

please also prebleed master before installation..

and when installing booster.. DO NOT BEND or wedge pushrod onto pedal... it will break plastic valve in booster shorten life...  

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 05/02/13
09:32 AM

autozone will have a vacuum diagram.. on their repair info web site.. look at the bottom of the emissions link onc you get logged in and in the repair info section......

i don't have time to link it right now.. perhaps tonight..