Brake peddle problem(HELP)
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Senior User
Joined: Mar 2003
Posts: 432
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From: up state N.Y.
Brake peddle problem(HELP)
I did the complete brake system on a 1994 F-150 2wd 300cyl,and this is what we did,We did EVERY brake line,every bit of front pad's,rotor's,calipers,and rear e-brake cable's,wheel cylynder's,rear shoes,drum's.It all bleed out great but then we quickly noticed our good hard peddle went south so to speak!We decided since the master had been dry for a couple of year's that would be the problem so we bought one,and bleed it,and installed on truck.We still have the same problem,If you pump 5-6 time's you get a super peddle,and if you stay on it,it don't fade away.It stay's.But now take your foot off peddle for a minute,and go to hit the brake's they go right to floor??The only thing not changed out is that little fitting on master cylynder that the rear brake line goes in.What is it,and could it be our problem.Look's like some sorta pitless valve sorta.A 7/8" wrench fit's it.This is like the most simple brake setup,and it is stumping us.Help if yea can with your idea's.I know we have every bit of air out of system.
Senior User
Joined: Dec 2005
Posts: 364
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From: Southern Delaware
I concur...or it could be a faulty RABS valve...my PEDAL was real spongy until I bypassed it...I read on here that a faulty seal in the rabs valve would allow fluid to escape past, causing a spongy pedal. I bypassed the valve and it solved it. however it does disable the abs, without making the abs light turn on....I would first advise bleeding the valve first-theres a bleeder screw on the prop valve so you can bleed it like everything else...
Thread Starter
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Senior User
Joined: Mar 2003
Posts: 432
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From: up state N.Y.
It has to be the valve,I bleed it at the portion valve on frame rail.Im getting straight fluid from every bleeder?How do you by pass RABS valve?Is that right on the master cylnyder?
Post Fiend
Joined: Jan 2005
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The RABS valve module is on the inside of the left side frame rail just about the drivers feet.
For your purposes it is easy to bypass it. If you look at it you will see a large hex bung. Unscrew this bung (against spring pressure all the way) and remove the spring that is inside the chamber (no fluid will come out). Replace the bung and pump the pedal a few times to fill the chamber.
If that solves the problem then the RABS valve module is faulty if no different then just replace the spring and look elsewhere.
This modification will not affect the brakes other that you will not have the RABS working which is not much use anyway.
For your purposes it is easy to bypass it. If you look at it you will see a large hex bung. Unscrew this bung (against spring pressure all the way) and remove the spring that is inside the chamber (no fluid will come out). Replace the bung and pump the pedal a few times to fill the chamber.
If that solves the problem then the RABS valve module is faulty if no different then just replace the spring and look elsewhere.
This modification will not affect the brakes other that you will not have the RABS working which is not much use anyway.
