Turning warped rotors is a big waste of money as they'll warp again (plug they're thinner). If a rotor is warped it's best to chuck both and replace them.

 

I'm going to hopefully re-open this thread. I have a 1998 Ram 1500 2WD. It has 340,000 miles on it, and the rear DRUM brakes finally started grinding. I tried and tried to get the drums off, but they wouldn't budge. So, I swallowed my pride and took the truck to the local Ford/Dodge dealer, and explained to them that I was going to do it myself, but couldn't get the drums off (apparently rust-welded to the hub). They said " no problem," and gracefully agreed to use the after market parts I had already purchased -- shoes, new drums, spring kits, and brake cylinders. They called the next day and told me it was ready. They also told me it took three mechanics, working together, with pry bars and an impact hammer to get the drums off (so at least my pride was partially restored).

I went to pick it up, left the parking lot, got up to about 40 MPH before I had to apply the brakes and come to a normal stop (city traffic). A violent shake started the instant I hit the pedal; the same shake wasn't present with very low-speed parking lot braking at the dealer. It felt like a front rotor was seriously warped, yet I knew that nothing had been done to the front. So I experimented by first pulling and holding the parking brake release handle and pushing on the parking brake pedal, the same shudder started immediately (I had barely begun to push the pedal). This action verified that the harsh vibration was coming from the rear brakes, and not the front, and that it had nothing to do with the hydraulic system (the emergency brake is engaged by a cable).

Most of the attempts to diagnose the original poster's problem were addressing the same thing that I would have first guessed -- warped rotors. In this case, we know it is not a case of warped rotors, and I already had the dealer try a second set of NEW drums, so I'm not thinking warped drums are the likely culprit here. Also, the harsh vibration had never once occurred in the 250,000 miles that I have driven the truck (purchased used in 2003).

Other symptoms. (1) When cold, the shoes tend to not release properly, putting an undue drag on the vehicle, as if the parking brake pedal was partially depressed (in an otherwise properly operating vehicle); the brake drag was sufficient to keep the truck from doing that slow roll that comes with idling the engine with the truck in gear and foot off the brake pedal. (2) The lower-speed vibration is not consistent, either in occurrence or intensity. (3) When the brake is warm/hot, the vibration seems to not be quite as severe, and sometimes quite light, (4) in the braking process from highway speeds, the vibration is the most violent at speeds in the 40-50 MPH range, (5) once it gets moving, the truck handles and behaves normally -- until the brake is applied, you would have no idea there is a problem, (6) there is no pull to one side of the other associated with the application of the brakes, (7) the actual braking effectiveness does not seem to be materially impaired with respect to the amount of pedal pressure applied; this is likely because 80% of the actual braking of a vehicle is done by the front (disc) brakes, and (8) I can smell the brakes after driving a ways and then standing near the rear wheel, such as when I'm putting gas in it; I never noticed this smell before on this truck.

The truck has rear-only ABS. I have never really known for sure if the rear ABS works properly (don't know how to test it). That said, the idiot light for it does work (appears momentarily at start-up) and is not coming on while driving/braking. I've never experienced any problem with the rear brakes locking up, so perhaps the ABS is working correctly.

Does anybody out there have an idea what the root cause of my apparent brake problem might be?

 

Pull the drums, and have them checked for 'roundness', or runout. Even new drums can be off. Getting two sets that are that bad though..... I would almost suspect something else is bent.

Jack up the rear, take off the tires, and thoroughly inspect the rear brakes. Make sure everything was put together properly. Take it from there.

 

we are going through the same issues after replacing the rear cylinders, shoes and drums.....baffled...

 

I am almost positive its your rear flex brake hose... this describes the problem i had with my durango to the T. The rear hose had deteriorated causing a flap to form on the inside of the hose which made it act like a check valve and not release pressure.