94 D1 brake problems

[chuck c]

Symptoms: very weak brake power. Can't lock the thing on dry pavement even at <5 mph. On wet, the right front will lock and the truck will keep right on going. It feels like only that one wheel is braking.

Had my shop check it out, they say everything on the axles is working correctly and it's an ABS problem. The truck sat most of this spring and summer, I've only put about 1500 miles on it this year. It probably has the original brake fluid. I thought it was a stuck caliper piston, the shop says no.

I need this to drive to work and I've had a few scary moments. I could really use some help.

 

[aliastel]

Pull the ABS fuse.

 

[teledan]

Have you bled the brakes? Pulling the ABS fuse will definitely tell you if it is the ABS or not.

 

[chuck c]

Have you bled the brakes? Pulling the ABS fuse will definitely tell you if it is the ABS or not.

Pulled the fuse, no better. However I did find my tires were badly over inflated, that's not helping. I did further testing (getting up to 40 or so and standing on it) and I can hear the left front squeal a little and the wheel is warm so it is working. Right still locks first and it's taking much more effort than I think it should.

I looked for vacuum leaks, it seems ok. I guess bleeding is the only thing left to do.

 

[Tims95Disco]

What does the brake fluid look like? Pull the cap and take a look. If your brake fluid is dirty, compared to new fluid, and if you say it might not have been changed for a long time, well you might have some problems.
Open the bleeder at the passenger rear and see what comes out. It would be helpful to have a Mighty Vac or similar tool to speed things up.

If it comes out black and nasty you need to refreash the entire system.

Check for brake fluid leaks under the master where it bolts to the booster. Brake fluid can leak inside the booster and ruin it.

Also make sure your vacuum conections to the booster are sound with no cracks in the tubing to the booster.

Get yourself the Rave manual.

 

[Max]

i had a bad cap gasket that acted the same way