yes, bled the front but they seemed to have cleared of bubbles up quickly.

 

thank you for clearing up my concern about additional vacuum.

ok heard loud and clear about brake bleeding duration. I am using an temp insert tool in the proportioning valve that is supposed to keep it from tripping. I've been using an bleed kit with a compressor to draw vacuum to bleed the brakes but i think im somehow inducing bubbles into the line . I'm thinking to go old school and just have my son pump the brakes.

I'll start all over on the back passager wheel, inside first, outside second.

quick question, I should see the calipers engage when the brake is applied, correct? Please also advise me where to look if it is the calipers that are leaking.....

 

I found the problem using a vacuum source at the caliper is that it will tend to draw air past the piston seals. It's possible that you have fluid leaking past the pistons, but if that were the case , then you would be seeing brake fluid in that area.

 

If a caliper is leaking it is obvious that you would see fluid dripping from the bottom of the caliper, from eather side of the caliper. Thats true you should use only internal pressure to bleed brakes, a vacuum pump works great to evacuate the old fluid but then you need normal brake pressure to bleed the calipers. A helper would be good. I have used a stick to lodge between the seat and brake pedal for bleeding a single caliper at a time checking for air. But to really bleed the brakes a big foot works great. Car does not need to be running. And no the only way to tell if a brake caliper is applied is to try to hand or bar turn the rotor, The pads touch the at all times you won't see them move unless you pry a pad away from the rotor first and apply the brakes. The best brake bleeder I ever used was a NAPA brake bleeder we used on the Farm, from race cars to trucks. It held a gallon of brake fluid, it had a diaphragm where you added maybe 15psi air pressure to the bottom then the top had a hose that was screwed to a steel plate and you had a choice of rubber gaskets that you clamped to the top of the master cylinder with a chain and screw handel. Worked great for bleeding and fluid replacement. Shark is correct for bleeding you need pressure, then drive it a day or two and then check for air again if needed.

 

I appreciate all the detail information. Very helpful. I spent the last 4 hours properly bleeding the brakes, in the correct sequence, until each line ran clear, no bubbles. I'm 100% sure I removed all air in all the lines. Unfortunately, with the motor running, the brake pedal, when pressed, still goes immediaty to the floor Time to take it to a professional. I really appreciated all the help.

 

I will be very courous what you find out.

 

I never understood how power brakes worked , but i'm wondering if the diaphragm inside the booster has ruptured.

 

II's almost like the booster is working to well. If the diagram is broken you wouldn't have any brake assist. Just a vacuum leak. when the brakes are appilied a vacuum valve is opened and vacuum is applied to the diaphragm helping you apply the brakes, after the brake pedal is released the diaphragm returns back to the release position from the internal springs and vacuum is shut off.

 

Thomas, regarding
the diaphram in the booster, I was under the impression that the diaphram was ALWAYS under vacuum. I did not realize that a vacuum valve opens when the brakes are applied. Could it be this valve is in the stuck open position? Is this valve internal to the booster or located somewhere else?

 

No, I don't think your valve is stuck open. If the brakes are bleed correctly the pedal shouldn't go to the floor booster or not, it might go to the floor if you stand on the pedal but that's not normal. Without inspection I'm not sure what you have going on. The only time I have seen a pedal go to the floor is with a leak or air in the system.