'97 Ram 1500 2wd with rear antilock only. Discs in front, drums in back.
I'm generally familiar with brakes but I have an odd thing happening. Every day when I first exit my driveway the rear brakes grab hard with the slightest of pedal pressure. On the gravel or sand, its all I can do to try and avoid locking up the rear tires as I look to make sure the coast is clear to get on the pavement. 100ft down the road at the stop sign, they're still a little sensitive but not as much. Its only for the first two or three full revolutions of the wheels with brakes applied that there seems to be a problem. There is no problem when I take my foot off the brake pedal. Its just that the rear brakes are hypersensitive for two or three revolutions when the pedal is depressed. After that, the brakes function absolutely fine for the rest of the day. There are no warning lights in the dash or codes stored. I routinely do not ever use the parking brake.

Some potential history: I've only had the truck for a short time and when I got it, the metal brake line going to the rear axle had rusted to the point of leaking out all of the brake fluid. The leak was behind the gas tank and I replaced the line. I bled all four wheels and I did it twice in both sequences -- back then front, and then front then back because I couldn't get a straight answer about the proper sequence. All of the fluid is new but I don't see how fluid could cause a problem like this. I had purchased new pads and shoes but the existing pads and shoes were all healthy so I did not replace them or disassemble the brakes in any way.

 

I have that same issue every once in a while, wet weather seems to make it worse but after the brakes get warm they are back to normal. I just recently worked on 1996 Suburban 2500 rear brakes, which had exact same symptoms (and exact same brakes as my 2500). New shoes, new small parts, new adjusters, old but still in specs drums. Still were acting up. Took them apart once again, noticed that shoes had made small pockets to the backing plate, I assumed shoes were sticking on them and when brakes were applied shoes would jump out of theit pockets and cause rears to lock. Not sure was that the culprit, because I had trouble to get parking brake adjusted, so I changed the RH cable while I had the drums off. Before I even touched the cable adjustment, I adjusted the drums. Shoes against drum, then few clicks back until there were no drag, then I took out the slack from the cable, after that went to the brake dyno and boom, never had such a good brakes on that truck! Next I have to replace the cables on my Dodge, as it has the exact same snafu on rear brakes.

Damn I hate drum brakes!!

But long story short, check the adjustment and use the parking brake. It should help to keep the rears adjusted.

 

You'll also want to use Sil-Glyde, or equivalent, where the shoes touch the back plate, similar to greasing your guide pins on your calipers.

 

My emergency brake hasn't working in years an I'm not buying new cables lol so I pull the rear drums every month to adjust the brakes. I also took out the self adjusters.

 

I have always used my park brake and I think it is a big reason that my pssgr side drum park brake lever became perm engaged and on driver side, shoes had expanded into the drum.
It is scary cuz I have no idea how long this went on and how much it has limited me in mpg, etc. I found this when I serviced drum brakes at 222K. Not sure if they have ever been done and I never knew that I was supposed to check adjustment every 6K, I think.

 

Pull your rear drums and take a good look. Is there any glazing on the shoes or rust on the drum? Is everything dry? Clean any dust with some brake cleaner. If everything looks good, no fluid leaks or discolored spots, get some 180 grit sand paper and lightly sand the shoes and drums. Don't sand hard, just break any possible glazing. See if this helps.

 

Pull the drums and see if you have any gear lube(leaking axle seal) on the shoes.