I have a 99 Tahoe 4x4 i just did a front brake job on this truck i turned the rotors, replaced thepads and bleed the system. and now there is a squealing sound when the break peddle is not pushed in. any ideas what is going on?

 

comeon nobody knows

 

I presume the brakes feel good when you apply them?Does the sound appear to be coming from one specific side, or both sides equally? Did you lube the caliper slides when you put it back together? There areonly three things I can think of to cause the squealing sound only when the brakes areNOT applied:
1) Slightly sticking caliper
2) Wheel bearing noise - caliper clamping brings it into alignment and noise goes away
3) Sqealer tabs (wear indicators)on brake pads touching rotors.

#1would be the most likely candidate. I'm not really sure how to check whether it is a sticking caliper slide or whether the piston is sticking a little bit, so I would eliminate items 2 & 3 and then replace the calipers if lubing the slides didn't work (You're supposed to use "caliper lube", but I was informed of this after using grease for quite some time). Not sure about a '99 Tahoe, but calipers for my '90 silverado are dirt cheap (~$17), but with a $50 core charge, so changing them aren't a terribly expensive proposition. Just the nuiscence of having to bleed the brakes again.

#2 is unlikely, given that the noise started right after the brake job. You can test for this by lifting the fronttires off the ground and pulling in and out on the top and bottom ofeachtire to check for play in the bearing. It's an easy test and you have to jack the vehicle up anyway to take the tire off, so worth checking.

#3 is VERY unlikely, unless you somehow bent the sqealer tabs during installation, but I can hardly see how you could do that unintentionally.

This all assumes that the metal dust shield behind the rotor isn't rubbing somewhere causing that noise. Should probably double check that just for giggles.

Chad

P.S. (Assumes rear drum brakes, not sure if applicable) When you did the front brake job, did you take the time to ensure the rear brakes were adjusted properly? It only takes a minute or two and you don't need to remove the rear tires. Supposedly, they adjust automatically when backing up and applying the brakes, but often times that's just not the reality. If not, I'd recommend jacking up the rear and spinning the tires by hand (e-brake off of course). If they go more than 1/2 revolution before stopping, they need to be adjusted. Normally, there is an oblong slot in the backside with a rubber plug. After removing the rubber plug, you can normally stick a screwdriver in it and by pushing the handle of the screwdriver down, it twists the adjuster mechanism to tighten it. If unsure, it's always a good idea to pop off the tire and the drum and convince yourself that is indeed the way of spreading the pads out toward the drum (i.e. tightening).