BRAKE PROBLEMS, ABS??

A CO-WORKER HAS A 93 BRONCO XLT 4X4 5.8 W/ ABS
SOMETIMES THE BRAKE PEDAL WILL TRAVEL TO THE FLOOR THEN NEXT PUMP THERE HARD AS A ROCK. THAT HAPPENS ONLY SOMETIMES. NOW WHEN APPLIED THE SECOND TIME THE PEDAL DOSENT BLEED OFF AND STAYS HARD.
NEW ROTORS, CALIPERS, PADS / SHOES DRUMS, AND MASTER CYLINDER. COULD IT BE THE ABS SYSTEM OR BRAKE BOOSTER?
[addsig]

Was the MC bench bled before install?

NO IT WAS REVERSE BLEAD WITH A REVERSE BLEEDER. NO AIR IN THE SYSTEM, AND IT ONLY HAPPENS SOMETIMES, WHICH IS WIERD, VACCUME LINES ARE ALL GOOD, COULD IT BE THE BRAKE BOOSTER OR SOMETHING WITH THE ABS???

I just have to chime in that I had an '88 Lincoln MKVII LSC and a '93 5.0 T-Bird, both with ABS and both had the worst-feeling brakes I ever had. The Lincoln had some funky high pressure system that always went soft after about 2000 miles, with decent calipers and with no evidence of leaking. A new master cylinder was something like $1500, and I ended up selling it. The T-Bird had a more normal looking vacuum booster setup, but it had no feel whatsoever, other than being annoyingly non-linear, soft and over-sensitive. No amount of bleeding or pad changing helped. I sold that one too. Just my conclusion that as of the mid-90's, Ford had yet to build a decent ABS system.

i know what you mean, i drive a 82 f150 with great feeling brakes. this is my co-workers and i drove it once and almost **** when the pedal went to the floor while towing a boat. but then next pump its great
[addsig]

I'd look at the prop valve to ensure that it is maintaining pressure in the front part of the system so the pads are kept at the proper distance from the rotors and the pressure isn't bleeding back into the MC.

It's possible the MC is bad but unlikely since it's so intermittent. Is their any pattern to this occurence at all?

I would suspect a a bad powerbooster, Despite the belief that power boosters do not sink when bad, I have seen this condtion on fords before. The High hard pedal is then the result of lost vacuum. Listen for a hissing noise under Dash. YOu may or may not hear it.

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<font size=-1>[ This Message was edited by: 1badmav on 5/31/04 11:24am ]</font>

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On 2004-05-28 21:48, 1 Bad 88 GT wrote:
I'd look at the prop valve to ensure that it is maintaining pressure in the front part of the system so the pads are kept at the proper distance from the rotors and the pressure isn't bleeding back into the MC.

It's possible the MC is bad but unlikely since it's so intermittent. Is their any pattern to this occurence at all?
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Typically unless the Caliper is bad this will not happen as Calipers require very little pressure to maintain clearance.
[addsig]

Also was this condition before or after the brake work??
[addsig]

the problem was before and after. the only things not changed are the booster, abs, and rear slaves, which arent leaking. just it being intermediant goofs me. i may just tell him to take it to mineke. haha maybe