When I am driving and apply moderate brake pressure, I get a very loud "bang" from the rear of the jeep. This is usually accompanied by a surge of sudden braking power from the rear, and I can feel it in the brake pedal. This doesnt happen when applying very light brake pressure, but moderate. Also, it usually will only do it one time per each driving cycle. Once it does it, it tends to not do it again until after Ive come to a stop and started moving again. It is not a continuous "bang bang bang..." until the jeep stops, but one single "bang". It WILL NOT do this if the jeep is stationary. It ONLY does it when moving. Also, if I am moving and slowly start pulling up on the e-brake, it seems to have no effect until I get to a certain point, then the "bang" happens and the brakes grab. But the e-brake works normally when the jeep is parked.
Also, I dont know how this could be related, but the other night I was troubleshooting this and took off from a stop relatively quickly, heard the "bang" noise again, and for some reason my back brakes grabbed pretty hard. Like the e-brake was pulled, but it wasnt. I drove it for a few seconds like that and the brakes released somehow. The e-brake handle and cable are new by the way.
The brake fluid reservoir is full and it is definitely not air in the lines. It is a very definite sound, like someone is hitting the underside of the jeep with a sledge hammer when it happens. Hopefully you guys can give me some help figuring this out. I would be glad to upload a video showing what it is doing if there isnt a minimum post count needed to upload vids. Sorry about all the "Bang"s lol.
Ok, lots of things to check: driveshafts, axle U-bolts, leaf springs for cracks/bushings, body cracks... but one thing that most people overlook is the condition of the brake backing plates. Take the drums off, clean everything (with brake cleaner, not an airhose) then look at the very small pads stamped into the backing plates where the edges of the brake shoes ride. They should be smooth and flat with no ridges or grooves.
I've seen backing plates that were so worn, the shoes wouldn't expand; they were caught in a groove. After enough pressure was applied, the shoes pop out and the brakes work. It's really important that these little pads be smooth for proper operation of the brakes. If they are worn, the only fix is to (a) replace the backing plate or (b) weld up the worn pad, then have a machine shop mill them back flat again.
The road goes on forever, the party never ends....
Awesome guys good info. I'm pretty much narrowing it down to the tail shaft, cylinders, or the shoes/backing plates. This is gomna be the first thing I tackle after I get moved into my house here in a week or two.