[ultraman]

i am restoring a 79 4wheel disc brake ta the brakes will not bleed and the parking brake does not work any help would be great.

[68ragtop]

Did you replace the master cylinder? If so, did you bench bleed all the air out of it before installing? Could be just too much air, or maybe the bleeders are plugged up? I like using a vacuum to pull out the fluid, but gravity bleeding usually works too. What parts have you replaced?

http://www.mityvac.com/hq_images/MV8000.jpg

[ultraman]

I put a new master cyl and 2 new front calipers because i broke the bleeders off.im not getting any fluid even with the rear bleeders removed.thefront bled out normally.The parking brake looks to have full travel.thanks

[kevin.1]

I had the same problem on a 69 Firebird & 69 GTO (nothing coming out of rear bleeders). Both were the same issue... rear brake hose was plugged. Never thought that could happen, but seems they fall apart inside and plug up the passage.

Quick check is to simply loosen the brake line where it connects to the rear hose then gently press the brake pedal.... fluid should shoot out of that loose connection (wrap a rag around it to avoid fluid spraying all over the undercarriage).

Good Luck!
Kevin

[77 TRASHCAN]

I went through some goofy contortions w/ my brothers 73 camaro.
Converted it to 4 wheel disc, (front stock, aftermarket rear). Had to use a vacuum pump w/ one of those bleeder cups to get fluid to the back.
Don't know the real problem...replaced the m/cyl that came w/ the kit, it solved all problems...

[bs78ta]

I am going with ragtop on part of this. The question was not answered Did you properly bleed the M/C before installing.

[2manyT/A'S]

The rear calipers are or can be a problem on those years......

The pistons have a ratchet mechanism in them which is activated when the parking brake is applied.....

If you don't use the parking brake,the rear brakes become inoperative....

You need to check that both rear pistons are adusted out enough for pads to contact rotors.

[ultraman]

Yes i bled the master cyl front and rear ive found the fluid going into propotioning valve nothing coming out.this car has been sitting up off road for a long time.can i use a valve off a disc drum car?

[77 TRASHCAN]

Originally Posted by ultraman

Yes i bled the master cyl front and rear ive found the fluid going into propotioning valve nothing coming out.this car has been sitting up off road for a long time.can i use a valve off a disc drum car?

No....!

[bs78ta]

Not if you want to stop . Must be a 4 wheel disc prop valve.

[Skip Fix]

Or just T the fronts and do an adjustable in the rear line.

Couble check the rear calipers also besides the line. the ratchet locks up frequently.

[68ragtop]

Is it possible that the prop valve piston slid so far to the rear its its blocking the rear passageways? I have never taken one apart, so I am not sure how far it can move.
Just a thought.

[ultraman]

That sound spossible Iremoved the end cap and the piston was toward the rear outlet fully.I might try to tap the piston in.thanks.

[68ragtop]

Is the brake light on? it should be on anytime the pressures get unequal & the piston gets pushed one direction or the other.

[ultraman]

I have the front clip off right now toput the engine and transmission in.almost to the point of hooking up power.just going from one bug to another.previous owner removed everything with a bolt most parts lost in trading hands.ive got it heading in my direction now.

[68ragtop]

you could check it with a multi meter. The electrical connector on the valve should have no connection when everything is normal. if the internal piston is off center it will short the pin to ground. (putting the light on if it was connected)

[ultraman]

will do a check with a multimeter thanks.

[ultraman]

today i found the line from master cyl to prop valve was clogged with a dirt dauber nest.I cleaned out the line with some wire and it bled out perfectly.now if i can get the parking brake to work.