brakes locking up bad

[mvsource]

i have a 98 tahoe with a bad brake problem. they have been locking up on me for a while now they tood me at shop that it was my calipers so i changed them out but that did not do it. i think its the abs but i dont know how to trouble shot it or what to look for. i have no lights on in the dash or any codes on the computer. any info will help thanks in advance.

[Fireplug]

need a lot more info

[rrousou]

If its the rear brakes...you've more than likely got a leaking axle seal which has contaminated the brake linings. Check to see if there is evidence of oil leakage on the backing plate.

[mvsource]

i checked the rear brakes but they were ok no leaks of oil anywere. what happens is when i step on the pedal about 1 to 2 in. into stopping they clamp up at a speed of about 10 to 20 mph. also it makes a noise like a vibration at the wheels

[Fireplug]

What wheel locks up? front rear left right both all ??
Any brake work done to the system and then the problem started?? Or problem just showed up 1 day??
Do you get a grrrrrrrrrrr sound when this happens and the brake pedal vibrates and or drops at all

[jthomp23777]

You seem vaque in your description. Did you buy new or rebuilt calipers? Did you change out the brake lines to the calipers? If you are going down the road at a low to medium speed and apply the brakes, does it pull right or left? When the brakes lock up, do they let go when you take your foot off the brake? Have you jack the front or back up and apply the brakes and turn the wheels to see what happens. Is this a constant problem or intermitant problem? Are the brake pads wearing down prematurely? Could be several things, just speculating at this time. It may not be a ABS problem. My Ford 150 had that problem and it was due to the linside ining in the caliper brake hose coming apart that reduce the back flow of brake fluid. The caliper pistons would not retract properly. It my understanding that these brake lines should be changed out somewhere in the life of the vehicle And a 1998. I would of change the caliper brake lines. They are inexpensive, hard part is bleeding the lines. Let us know, we all learn... Good luck...

[GMMerlin]

Originally Posted by mvsource

i checked the rear brakes but they were ok no leaks of oil anywere. what happens is when i step on the pedal about 1 to 2 in. into stopping they clamp up at a speed of about 10 to 20 mph. also it makes a noise like a vibration at the wheels

you need to be more sepcific!
It sounds like you have 1 of 2 senerios going on
1. BRAKE PULSATION...a warped rotor caused by excessive lateral runout or parallelism
Or a out of round drum...
if the rotor or drum are within safe specs they can be trued..if not they will have to be replaced
2. low speed ABS activation caused by an erratic signal from a wheel speed sensor...cleaning the sensor and reluctor ring helps.

[mvsource]

the rotors were re-builts from checker auto parts and i did not change out the lines. i had some one drive and stop i front of me a saw the the back brakes are making a loud sceech when we brake.and the back wheels lock up. it sounds like buss brakes. i've had the problem since i bought the truck but it got worst with time. the brake pads are wearing out evenlly but i did not have chance to check back ones.i did notice that the master cylinder was a little low in fluid since a week and half ago.and they do not stay stuck in place, they let go when i let out the pedal. i had the rotors turned at a local autozone when i relaced the calipers and they were fine it was there first cut on the surface i guess they were new and the owner before me thuoght that was the problem. and they do make a grrrrrrrr sound when im driving at a speed above 45 mph. and try to make sudden stop or slam the brakes.

[2kflhr]

Pull the ABS fuse test drive it and see if PSE.

[decoy86]

I have had several problems with my 99 tahoe brakes. First thing take off the Checker Rotors and go back the stock composite rotors (not everyone can turn these). I had put the same Checker rotors on mine too and they were horrible. Also rebuild/replace the caliper mount bolt hardware. There are 4 rubber bushings on each caliper. Replace them and you may also have to replace the mount bolts too. This will allow caliper to float on the rotor. If you buy the new Raybestos ceramic brake pads, they include all the dust caps and bushings along with the pads.

We have 96,000 mile since new on it and I have done at least 4 front brake jobs and one in the rear.