I feel kinda stupid but I forgot what the dang black box on the side of the brake master cylinder is, could some one please refresh my old brain, thanks.:screwy:

Since you didn't list what the truck is, I am going to guess that you are refering to the abs contoler.

Oops, sorry bout that the truck is a 91 2500 8600 gvw model.
I didn't think abs because my truck is too old, no abs warning light etc,
I have been trying to locate my book on the truck but since we moved a couple of months ago I'm having no luck.
the reason I wanted to find out is, if the box is for some sort of anti lock for the rear it may be malfunctioning, the left rear is locking up for the first few stops first thing in the morning, with little pressure on the pedel, "only if the ground is damp I should mention", but with all the rain we have gotten around here this has led to some severe puckering moments, and the last thing I need early in the morning is to pucker that hard,
for the past year I have carried a camper on the truck most of the time and seems like the truck still thinks the weight is still on there, brakes are good and properly adjusted, drums are good, rebuilt cylinders 1.5 yrs ago, pulled the drum last weekend and everything looks good,
i'm pretty picky about my brakes since I do have a load of one sort or another on the truck often, thankfully though it has never locked up with either the camper or while hauling toys,
kind of thinking that maybe the shoes are sub par even though they look good and still close to new looking.
but wanted to check other ave before I throw $$ at it.thanks for the input so far

Oops, sorry bout that the truck is a 91 2500 8600 gvw model.
I didn't think abs because my truck is too old, no abs warning light etc,
I have been trying to locate my book on the truck but since we moved a couple of months ago I'm having no luck.
the reason I wanted to find out is, if the box is for some sort of anti lock for the rear it may be malfunctioning, the left rear is locking up for the first few stops first thing in the morning, with little pressure on the pedel, "only if the ground is damp I should mention", but with all the rain we have gotten around here this has led to some severe puckering moments, and the last thing I need early in the morning is to pucker that hard,
for the past year I have carried a camper on the truck most of the time and seems like the truck still thinks the weight is still on there, brakes are good and properly adjusted, drums are good, rebuilt cylinders 1.5 yrs ago, pulled the drum last weekend and everything looks good,
i'm pretty picky about my brakes since I do have a load of one sort or another on the truck often, thankfully though it has never locked up with either the camper or while hauling toys,
kind of thinking that maybe the shoes are sub par even though they look good and still close to new looking.
but wanted to check other ave before I throw $$ at it.thanks for the input so far

I have a 90 K1500 and I bought in new. It has RWAL (Rear Wheel Anti Lock). I am not sure what year they went to 4 wheel anti lock but you probably have RWAL with a 91. On my 90, the brake light will flash if there are issue with the RWAL controller.

//2000CAYukon

Have you checked for a leaking wheel cylinder or wheel seal on the side that is skiding?

Thanks for the info on the abs, yes I have checked the cylinder, and they were replaced not too long ago, Since the rain has let up I figure ill just start at the booster and work my way back, bound to figure it out this summer.

[quote=fuzzypuppy]Thanks for the info on the abs, yes I have checked the cylinder, and they were replaced not too long ago, Since the rain has let up I figure ill just start at the booster and work my way back, bound to figure it out this summer.[/quote


if it is only when it is damp outthan it is probably justbrake dust and nothing to worry about just blow off the shoes.............