90qt

I HAVE 1987 5KQ (395 000 KM)HERE`S THE PROBLEM.JUST RECENTLY,3 DAYS AGO,MY ABS WOULD NOT WORK WHEN I APLIED BRAKE LIGHTLY,IT WOULD SKID FIRST AND THAN WOULD COME ON.IF I STEP ON BRAKES HARD,WORKS INSTANTLY EVERY TIME.MASTER CYL IS 7 MONTHS OLD.ABS LIGHT IS NOT ON.ANY IDEAS.THANKS.DAN

Randolph

If I'm understanding your post correctly.............It sounds to me like your ABS is working the way it should.
Randolph
87 5KCS
97 CAB (sold)
93 928 GTS

90qt

NO.IT WORKED PERFECT BEFORE.ABS WAS COMING ON RIGHT AWAY,NO SKIDING AT ALL

SteveJ_in_TX

First of all, can you turn off the caps lock?

Now, is the ABS functioning when it shouldn't? In other words, dry road, easy stop, and it kicks in (pedal vibrates and you get that ohhhhhhmmmmmm sound in the engine compartment)? Or something else?

Typically the ABS gets squirrelly when one of the sensors gets bumped or whacked out of alignment, or the teeth that send the square wave to the ABS computer get gunked up with rust. These teeth are located on a ring on the drive axles right next to the outer CV boot.

Let us know...