Ok, this is for a friend of mine he has 1995 F-350 460 4x4 srw with the 9000GVW package.

About a year ago his brake pedal started getting softer and softer, so last summer we replaced everything on the rear including shoes, cylinders, hardware, master cylinder, and the RABS valve.

Nothing changed the brakes work and will stop you but, the pedal after initially pressing on it will go to the floor.

So today we did every thing on the front hoses and calipers. Everything has been bled out 10 times and still low pedal. With the ABS sensor unplugged you can slam on the brakes and the rears will lock up for about 10ft. and the fronts will never lock up and the pedal still continues sinking until it physically hits the flow.

We even read in a Napa book that '95 F-350 had a problem with low pedal on some trucks, if so use this "other" master cylinder and we have had 3 on it and none of them do any different.

We have talked to a couple shops and several dealers no one can figure this out.

Please help, truck is used to tow 10,000 pounds daily and the brakes are needed.

Thanks
Brian

 

Check you vacuum booster for leakage. If not, there is residual air in the system somewhere. Have you power bled the brakes or is it the old tried and true, "OK Bob pump it up and hold it!" method. It is very easy to have some air in your calipers. Did you bleed the RABS? I hope this helps, I understand the routine towing usage and I'd rather have good brakes than more power if that had to be the option.

Tex

 

There is no air in the sysytem it has even been bled twice by a dealership. Yes the RABS was bled also.

 

Hi,

Had the same problem with my F250. Turned out to be a faulty ABS valve. This allowed fluid to enter the spring loaded piston at all times and so the pedal slowly sank to the floor. I see that you did replace this. Could the new one be faulty or could you have an electrical fault in the ABS. You could check this by taking the cylinder shaped housing off the ABS valve and removing the spring then replace housing and bleed. Pedal should then stay high if the unit was faulty.