1999 Ford F-350 brakes are mushy and shutter

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MEMBER
1999 FORD F-350
V8
4WD
AUTOMATIC
120,000 MILES

1999 Ford F-350 crew cab 4x4 Cummins mileage: 120,000 truck. My brakes from day one were not the best. I put in a Cummins diesel and now I pull big loads. I can't panic stop and they seem mushy. I replaced everything the vacuum booster, master cylinder, proportioning valve, calipers. Now its worse. I have bled them several times and adjusted my rears up close. Sometimes they shutter when I stop hard and now even pull to one side. I know the R.A.B anti lock things don't work right because my rears will lock up. I don't get any fault codes, now what?

2 Replies

2CP-ARCHIVES

MEMBER
4,540 POSTS

We suspect that rear antilock break valve is faulty here. Also, check the vacuum supply to the power brake booster to make sure it is sufficient.

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Friday, February 11th, 2011 AT 11:21 PM

MADMIKE1735

MECHANIC
951 POSTS

Im not 100% positive, but I do believe 1999 and up you have to bleed the abs modulator, and this is done with a diagnostic tool such as a snap-on modis. Most garages have them. Once that is bled, then the ordinary brake bleeding needs to be done.