1997 K2500 Suburban brake questions.

[0913]

My problem has two parts:
1. My original brake issue started with what I thought was warped rotors. After driving at about 45 MPH and above for about 15 minutes and then lightly applying the brake, I expierienced excessive shuddering throughout the vehicle. The syptom seemed like one of warped rotors. There was no feedback in the wheel but never the less I thought they could be out since the truck has 82,000 on it. The tires on it were Firestone Steeltex R4s 265/75/16. I replaced them with BFG AT TA 265/75/16's along with having the rotors turned by my trusted local mechanic. Needless to say, the vibration shudder is still there even after the brakes were turned. In order to narrow down the problem, I took the truck out on the freeway at night and held the e-brake release latch while stepping on the e-brake pedal. This did produce some pulsing and could be the source as it is a solid, leaf sprung rear axle. I am going to have the drums turned to see if this solves anything. Suggestions? This is very annoying as I pull a 30 foot trailer with this rig and need to be confident in my brakes.
2. After getting the truck back, now I have a new brake problem. At slow speed stopping (creeping through a parking lot), I periodically get a groan from the front brakes along with a little pedal fade and what feels like ABS engagement. This does not happen all of the time and is usually most notable when the brakes are cold. My mechanic assures me it is due to the pads seating on the new surface and that it will go away but I am not convinced. I have driven about 300 city miles since the brakes were done. This problem only surfaced after the rotors were turned and there was no evidence of it before then. Is it possible that they disconnected something when the pulled the rotor assembly? I am aware that on the 2500's, the rotor assembly also contains the components for the hub assembly (bearings etc). Are there ABS components that could have been altered by this process?

Other than the instances listed, the brakes stop great and I have had no problems during pannic stops at under 45 MPH.

If anyone knows something that can save me long expensive diagnostics please reply.

Thank you!

[autopro43725]

I have the exact same problem. My pads,rotors and drums all appear to be good. I am interested to know if anyone has come up with any solutions.

[teaguem01]

Originally Posted by autopro43725

I have the exact same problem. My pads,rotors and drums all appear to be good. I am interested to know if anyone has come up with any solutions.

I have a 96 K2500 GCVWR 8600.

I had a problem where the Pass Front Caliper was not disengaging the discs from the rotor and was heating up the rotor and causing a lot of pulsating.

Drive your Sub a while and remove the hup cover and see if the wheel is hot.

This may be your problem.

[chuck's]

The groan that you get,is that the ABS motor kicking in??? I have come across a TSB that talked about the ABS wheel speed sensor. It has to be removed and the surface of the hub where the sensor sits against has to be cleaned. I believe what is happening is that rust is forcing the sensor further away from the trigger wheel and at slow speeds and the ABS computer is getting a false reading. The sensor must be removed if the rotors were turned. Unless the rotors were turned right on the vehicle. Is it possible that the sensor is not all the way in the hole?? I hope this will help you.
chuck's

[fireproof74]

I have a 1999 GMC Suburban and I get a pulsing feeling coming from the break pedal. I replaced the front rotors with Napa premium rotors and ceramic pads. Some of the pulsing went away, however I still had some pulsing sensation on the pedal. I just replaced my two rear drums and shoes with Napa premium drums and I still have a slight pulsing feeling. I read that I should replace the thru-bolts and bushings on the front calipers. Has anyone heard of this? It seems like a good idea. Well at least I wont need to drop $300 on drums and shoes for a while. As a reply to the grinding issue of the previous post, I think you should pull the rotors and check your bearings, sounds like they are either bad or about to fail. I had a similar problem with my s-10 and i bought new rotors and bearings, runs like a champ now. I hear alot of Chevy stories with brake problems, mainly due to salt or water corroding the bearings somehow and then sending false signals to the ABS system.

[chuck's]

You should make sure that the caliper slides freely on the mounting bolt.Sticky caliper slides can cause the brakes to stay on and heat up the rotor.You don't want to throw 300 dollars prematurely.
chuck's