rear disc brake problem

[DGerth]

Had to do a rear axle bearing seal replacement and noticed that the calilper "tracks" on the rotors seemed to be narrow and had rust on them as if not functioning properly, not enough clamping pressure being applied. Has anyone had this problem/cure? This is a 01 6sp 2500 with 300k miles.

 

[seafish]

Important Question is:

When was the last time a full brake fluid flush and complete brake service (other then a simple had replacement) was performed on the truck??

Problem is:

Likely a combination of contaminated brake fluid in the brake lines and caliper and/or sticking caliper pins.

Solution is:

Complete inspection and dissassembly and cleaning and R&R of brakes at caliper coupled with complete brake fluid flush and possibe caliper replacement with new caliper made by Raybestos Opti-Cal brand available from Summit or even Amazon for about $100 per caliper.

 

[Chief USA]

I just got done with this on both of our trucks. Both were having problems with the brakes overheating on anything other than a very short trip around town. I tried totally disassembling all 4 brake assemblies. They were the OEM original brakes when I purchased the truck new and the pads still had over 75% pad remaining after almost 17 years! The exhaust brake is worth every penny. The brake assemblies were all pretty rusty and extremely difficult to remove from the caliper mount and rotor. The slide pins came right out but the calipers required a block of wood and a deadblow hammer to gently and gradually get them free. I cleaned up everything and lubricated everything with hi temperature disc brake grease. I flushed the entire brake system with new fluid. Reassembled and still had the same problem.

The caliper pistons were seized and had very little free and easy movement and were just shot. They could be pushed out but required a big C clamp to force them back into the caliper bore. NOT good. The original rotors were good but had gotten VERY hot a few times. I elected to upgrade to the Centric HD slotted rotors and Centric replacement OEM rebuilt calipers loaded with Posi-quiet pads. I also replaced all of the brake hoses to each wheel/brake assembly and the rear axle brake hoses. I had forgotten what the brake worked like since the truck was new! VERY smooth and VERY little pedal pressure required. The brake pedal almost felt soft compare to the old seized calipers.

The brakes on my truck had about 87,500 miles on them since new. As you can surmise, this truck sets for long periods of time. I believe the problem is the repeated cycles of condensation of moisture on the brakes and other components over time causes rust and corrosion to take its toll. Not changing brake fluid every 2 years like the manual calls for does not help either. It IS a very important part of maintaining the brake system. I would suggest that every 2 years is a good measure to inspect and lubricate/clean up corrosion while flushing the brake system will go a long ways toward keeping the brakes working well.

Just checking the master cylinder fluid level and how much brake pad material is remaining just will not cut it.

 

[crabman]

Here is a good link on the important aspects of brake hardware and the 'how to' do a proper brake repair, especially if you live in the salt belt.

 

[B.G. Smith]

I believe the proportioning valve for the rear brakes on a 2500 is mounted on driver side over rear axel. It reacts to load in bed and I think it is adjustable.