Hey all, I've got a 2002 sierra 1500. I installed all new rotors/pads just a few months ago. They are wagner brand.
The truck has been braking fine... I started to have a very unusual problem however. At normal speeds everything is ok as I stated. The problem I have is low speed... in driveways, pulling into parking spots,etc..
The pedal will become very hard to press down and sounds like a grinding noise coming from the pedal. And it won't stop!
I'll start driving again an they are perfectly fine.
I've been thinking either a air pocket in the lines, brake booster?
Vac seems to be fine and the truck runs fine.

 

maybe a stupid question but did you take everything apart to make sure nothing is jammed up? like a stuck caliper or a jammed up pad up front or broken spring in the rear drum assembly?

 

It doesn't have any drums. Its rotors front an back. Mechanically everything is sound and working. No fluid leaks,level is also correct. I've never seen anything like this. Thats why I'm more leaning in the computer...direction.
No codes by the way except for the infamous PO440,PO449 but thats another thread.

 

Is your ABS light on by any chance?

 

Unfortunetly it is not. Its a intermittent problem doesn't always happen but does happen at least 5 times a day. Heck yesterday pulled into Lowes and end up going over the curb cause it wouldn't stop. A bit embarrassing..lol. When I do have the problem there is no ABS light as well.

Pulled it back into the spot and stopped fine. Drove it around town today, stopped at 4 different places and only once had the problem.
Looks like I'm gonna have to suck it up and take it to a dealer.

 

Sounds like a booster issue. The diaphragm might be catching and not sealing. Unplug vacuum from the booster and see if the petal feels similar to when you are having your brake issue. If it feels similar, replace the booster.

 

Thats a good idea.. I will do that an report back

 

Sound like a bad gmc sierra 1500 brake booster. Have you checked it?

 

Well I disconnected the vac line to the booster. Its not giving me the same problem that I already have thats existing. Just removed both front tires and the rotors/pads/calipers all look as they were when they are new. Calipers aren't hanging up as well.
So I've elimated those...brake booster has been elimated. Now I'm down to speed sensors I guess.
Drove it again this morning..only problems I had were pulling into parking spots... no place else. When pulling in you get this grind nose and the pedal goes totally hard and can't stop. Have to throw it in neutral. Since its intermminate like this it almost has to be electronic somehow.

 

It still sound mechanical at this point. If you're sure it isn't the ABS trying to kick in, then it's got to be something mechanical. Try unplugged a wheel speed sensor. If it isn't the caliper pins getting stuck in the caliper and the thing isn't moving, it's got to be the ABS pump kicking on and keeping your foot out of the pedal.