Dakota Brake Issue

[JOEX]

Specs....
'94 Dakota
2wd
v6
115k+ miles
Rear ABS (at least i'm pretty sure it's rear... it's not 4w abs)

Pads & shoes replaced at different times in the last 2-3 years.
Rear wheel cylinders rebuilt at the same time.

The issue...
Took the truck out the other after sitting for a couple months and after charging the battery.

When applying the brakes the dash brake & abs lights come on.
When releasing the pedal the tach makes a quick drop of about 1k or so with no difference in engine rpm. Brake & abs lights go off about a second later. The lights are in the same part of the dash as the tach if it matters.

Pedal is very firm but several times under braking it would move down further in 'jerking' or 'stepped' fashion as opposed to a smooth pedal drop like if there was a leak.

Any ideas for cause and repair?

[300exOH]

I would check for any vacuum leaks at the master cyl. Also check all you brake lines for leaks. You may also need a wheel speed sensor...not sure on the earlier models but on my 98 Dak (rear ABS only also) it is in the rear diff housing. Could even have a bad master cyl but I would check the other items first.

[wilkin250r]

You'd be surprised at the goofy problems that can be solved simply by removing the battery cables, and forcing the onboard computer to reset itself.

[j450rking]

the stping your talking about most of the time is a bad master cylinder.