Brakes gripping and causing skidding

Question

I'm experiencing a problem with the brakes on my 1994 Jeep Grand Cherokee. I replaced almost every component of them over the course of the 2 years. Most of the replacements occurred in April 2012, because of problems similar to what I am having now.

Front brakes: (disc)

• In April 2012, Replaced all pads and rotors
• In Mid-2011, replaced caliper on driver-side disc brake
• In Mid-2010, replaced caliper on passenger-side disc brake

Rear brakes: (drum)

• In April 2012, replaced both sets of shoes
• In Early 2011, replaced both drums

When I completed the repairs in April 2012, all of my brake problems completely went away; the car stopped perfectly. This lasted for about 3-4 months. Symptoms started popping up again in August. When braking, even a light tap on the brakes can cause the car to start to skid, even after the brakes have been in use for 10-15 minutes.

It feels like it is the drum brakes locking, but I don't know for sure. Do the self tensioners sometimes over-compensate and need to be backed off? One more useful piece of information: back in August when the brakes began manifesting problems, it felt as if the brakes were catching due to uneven areas (while applying the pedal slightly, you could feel a drag-spin-drag-spin on the vehicle.)

** EDIT **

Two other things to note:

• The tires are only about 9-10 months old. Plenty of tread, 5-6K miles on them at most.
• The skidding can happen at VERY low speeds, even under 5 mph, while barely depressing the pedal.

Answer 1

Four things come to mind.

The first two could be a result of mileage or age.

• The axle seals may be leaking gear oil on to the brake shoes. The oil will make the shoes grabby (if that is a word). The effect is that the shoes tend to grab or stick when applied. If the leak is slight, it may not have been noticed when the shoes were changed. Over time it slowly contaminated the shoes.
• A slight leak in a brake wheel cylinder will have the same effect as above: the brake fluid will make the shoes sticky.
• As drum brakes have become obsolete technology an alternative problem may be incorrect reassembly. Typically the shoes on each side consist of a long shoe and a short shoe. The long shoe is usually facing the rear, the short shoe faces the front. The length difference may be less than 1/2" so it is easy to miss the difference.
• Also the automatic adjusters look identical. They are not however and have a left and right side. The left side is left-hand thread, the right side is right-hand thread. Switching either the shoes front to rear or the adjusters left to right can cause a myriad of problems. From continuously being out of adjustment to banging on application, parking brake malfunctions and lock-up problems.