rpace@[EMAIL PROTECTED]
wrote:
> I just purchased and put on a disc brake conversion for a 1968-1972 GM
> A body car. My car is an 1971 Buick GS with the 350 Stage 1. I
> purchase the kit off of ebay from waterloo tire company out of Iowa.
> Of course it came with no instructions. I put on the parts myself and
> could not get it to work. I took to local mechanic and he can't fiqure
> out why it won't work. Here is a summary of what we did:
>
> Installed new bearings, spindle and rotors. New SS braided hose. New
> chrome power booster, master cylinder, pro****tioning valve and lines
> from mastercylinder to pro****tioning valve. Had to get new lines to
> rear becuase could not get fittings to match. Had new rubber brake
> hose made from front to rear.
>
> Here is what she is doing:
> When car is turned off I have hard pedal. When cranked there is no
> pedal. I have bench bleed master several times and power bleed it. I
> can't get any pedal when it is cranked. No stopping except a if not
> going fast rear brakes will lock up and gradually stop the car. I
> plugged the master cylinder and it has hard pedal.
>
> Any suggestions on what to do?
>
If the brakes work and you have a good pedal when the
engine is off, and then the brake pedal sinks to the
floor with the engine on, the problem is the booster.
"The booster is an empty shell that is divided into two
chambers by a rubber diaphragm. There is a valve in the
diaphragm that remains open while your foot is off the
brake pedal so that vacuum is allowed to fill both
chambers. When you step on the brake pedal, the valve
in the diaphragm closes, separating the two chambers
and another valve opens to allow air in the chamber on
the brake pedal side. This is what provides the power
assist."
http://www.familycar.com/brakes.htm
Essentially, you're getting too much vacuum assist.
--
..boB
2006 FXDI hot rod
2001 Dodge Dakota QC 5.9/4x4/3.92
1966 Mustang Coupe - Daily Driver
1965 FFR Cobra - 427W EFI, Damn Fast.
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