1992 Chevrolet Astro Repair Question
Chances are there is no air in the system unless you had it opened. If the rear brakes are not working, check for leaks, check to make sure the brakes are properly adjusted... If they still are not working, chances are you have a bad master cylender or proportioning valve (unlikely).
If you still want to bleed the brakes, you will need a helper. To bleed them, locate the bleeder valve on the backing plate of the rear wheel. Have a helper pump the brakes 3 or 4 times, keep pressure on the brake pedal, you open the bleeder and air or fluid will come out causing the brake pedal to go to the floor. The helper must hold the pedal down until you retighten the bleeder. Otherwise, the system will suck air back into the system. After the bleeder is tight, repeat the process until all air is out and sold fluid shoots out. Tighten the bleeder and that wheel is done. NOTE: Start at the wheel furthest from the master cylender, the passanger side rear, then the driver's side rear. Also, be careful with the bleeder. They love to rust in place and break when you try to loosten them. That usually leads to needing to replace the wheel cylender. Also, keep a close eye on the brake fluid level in the master cylender. It will drop quickly when doing this. If it goes empty, then you have air in a new section of the braking system.
I have attached a picture of a wheel cylender. You will only see the back of it where the steel brake line screws into it. The steel thing sticking up is the bleeder.
I hope this helps.
57,475 answers provided