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Brake Bleeding Problem
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Author:  Greg Ondayko [ Thu Jul 23, 2009 6:11 pm ]
Post subject:  Brake Bleeding Problem

I am in the process of getting my project valiant able to drive and stop on it's own.

I have put on New Brake Lines all around and I am also using a new Master cylinder.

I converted this car from drums to disc up front So I put on a Used A body Prop Valve from a 1975 dart w/ factory discs.

The problem is I cannot get a firm pedal.

If I pump it up it's good, but otherwise it's soggy.

I have bled all 4 wheels multiple times and it's always solid fluid.


Could the Prop valve be the culprit??


Thanks, Greg

Author:  Pierre [ Thu Jul 23, 2009 6:28 pm ]
Post subject: 

Did you bleed the m/c on its own before hooking the lines up? The bleeders on the calipers are pointing up, right?

Author:  Greg Ondayko [ Thu Jul 23, 2009 6:30 pm ]
Post subject: 

Yep and Yep.


Greg

Author:  VDART [ Thu Jul 23, 2009 6:51 pm ]
Post subject: 

I have heard but not experienced a prop valve with an air pocket -- that causes this situation. Maybe bleed the valve similar to the brake procedure. Pump the brake & break the connections loose at the p/valve. Lawrence

Author:  Greg Ondayko [ Thu Jul 23, 2009 7:12 pm ]
Post subject: 

Lawernce, Thanks,

I am going to re- Bleed the MC to be sure and then I will do as you say as well.

Thnaks,


Greg

Author:  SlantSixDan [ Thu Jul 23, 2009 7:19 pm ]
Post subject: 

I did some reading up on exactly this problem with the '76 combination valve in my '64 Dart. The '76 FSM says to crack a front bleeder and step on the brakes as step #1 in the bleeding process, then close the front bleeder and proceed normally (right rear, left rear, right front, left front) so as to prevent air entrapment in the combination valve. There's also the possibility (haven't researched it fully yet) that the holdoff valve stem has to be held open with a special tool during bleeding. Don't know if your '75 valve has a holdoff; it's a small round stem protruding from the middle of a round rubber boot at one end of the combo valve.

Next time I'm in Seattle, I'll try that technique and see if it fixes my low/spongy pedal despite new/bled master cylinder. Let us know if you try it how it works out!

Author:  Greg Ondayko [ Thu Jul 23, 2009 7:32 pm ]
Post subject: 

Dan, My Valve Does not have that Hold offf pin like the B, E, and FJM and Truck Valves do.


Thanks for the Tip!


Greg

Author:  Greg Ondayko [ Tue Jul 28, 2009 6:50 pm ]
Post subject:  Found My Problem.

Quote:
Did you bleed the m/c on its own before hooking the lines up? The bleeders on the calipers are pointing up, right?

Well The Problem was the caliper Bleeders.

I am Using 79-down F body calipers and adapters etc. that are "flipped Side for side to avoid any bad hose routing issues..

I used 80 F body Hoses to work with the Calipers. etc. The problem was the Bleeder screw was Indeed pointing up, but not at the very top of the caliper / piston assembly so after taking the prop. valve out and rebuilding / cleaning it and re bleeding all four corners again and still getting a mushy pedal, I bled the calipers off the ways with a C clamp and manuevered them in such a way that I would get the bleeder screw to the top to get all the air out and Bingo Firm Brakes.

I might Have to invest in a set of 1980- up FJM calipers somtime when I have to bleed the front calipers again!

Greg

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