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What is the correct method of bleeding brakes on 77 Vet. Shop has put in New Master C, New GM Proportioning Valve and brakes still spongy. Pedal to the floor and on power can still move vehicle forward easily. They have been using the "You pump brakes - mechanic Bleeds. Asked them if they shouldn't use a Power Bleeder. Later I asked a GM Mechanic and he said that you had to power bleed them to get all the air out and to get solid pedal pressure. Is anyone on this site a pro at this. Appreciate the help.

E/J Vancouver Island, Canada
Foot Note Calipers - Stainless - New Pads and no leaks on lines or caliprers
 

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It's a VERY simple system..... They are missing something!!!
If you "pump" the pedal .... does it get harder???=Air in line or seized caliper or collapsed line... see if you've got a wheel dragging with the brakes off or a wheel not dragging with the brakes on
Does the pedal "sink" when you hold the brakes on??=Leak or bad master cylinder
Do the brakes "vibrate" when you stop??= Warped rotors
worn-out wheel bearings/spindles can also play havoc with your brakes but you'll get good pedal 'till you drive it!!
hope this helps:thumbsup:
 

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Everything appears to check out. The GM Mechanic said if you bleed them like a normal vehicle - when you pump the pedal before the mechanic opens the bleeder - the proportioning valve just shuts off the back brake line because both lines aren't pressured at the same time. Said if the power bleeder is used - the system is sealed and it can't. He said that the dual pistions create a little more problem getting the air out.
I don't know but I am sort of stuck with finding out for that shop or I have to take it to a GM Shop. Don't really like doing that because they have no mercy on you when it comes to replacing parts.
I am generally watching when they are working on it.
It is my wife's car that she has had since new. Just rebuilt the engine, rad etc complete for a cost of 8000 Canadian ..... uh 5900 USA $
 

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Make sure they are pulling all 4 tires and bleeding at both places on each caliper... make sure the bleeders are on top of each caliper (I've seen calipers on the wrong side, bleeders on the bottom... not on a 'vette but I've seen it)
A pressure bleeder is best but the master cylinder on a 'vette is the higher than the lines and calipers so its not a "must have"
 

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you can buy a pressure bleeder on line for about 40 bucks. i made one out of a one gallon pump sprayer...damn thing worked great.....and the proportioning valve never reacted like stated.

another way is gravity bleeding...takes a long, long time. some people swear by that method.

yet another is vacuum bleeding. you can buy a vacuum bleeder and use that, but be sure to keep the m/c filled always!!

lastly, the pump and bleed method....have done that with the wife several times.

the pressure bleeder worked best for me. i did that two summers ago and they are still fine. but, i'll replace the fluid again in the spring. using a pressure bleeder is a one man operation and quick.

be sure bleeding is done in the proper sequence!!!
 

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Discussion Starter #7
For what it is worth - I sent a email to Parma Officials saying that I would not be moving there and attached your article. Little Help- Who Knows.
E/J- [email protected]
 
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