Rear Brakes dragging INTERMITTENTLY 2008 dodge ram 3500 4x4 slt quadcab

[BernardMcPhillips]

hello there
i took off from the curb and noticed some drag on the truck. tried reverse, checked the handbrake, checked 4hi and lo switch. thought i'd take it round the block, and after parking the brakes released by themselves. so i went on my way and drove maybe 8 miles to a buddies house. it happened on the way again and i could smell the brakes as i got out.
in order to prove this to my buddy, we slow tested it for about 400 yards. same thing, after jacking it up and spinning the wheels, we determined that the brakes had freed up again.
we ruled out the e-brake and the calipers since it is intermittent and because the rotors were hottest on the disc section. checked the short rubber brake hoses and they seem fine with no clips choking them. i've read a lot of forums but all of them have been on just one wheel. today i will test the slides to make sure they are free.
it seems weird that it happens to both, which leaves me to believe it might be up around the master cylinder/booster/(return line maybe) or before the split in the hard brake line. i haven't traced the lines to see how they are configured. since there is only three coming out of the M/C i am assuming that one goes to the front and 1 to the rear and the other is maybe the return. it seems to me that since it is only happening on the rear brakes, it would have to happen independent of the front brake lines, which means there may be a separate return line for front and rear. i just bought this truck 3 months ago (265,000 miles)and took it on a 3000 mile maiden voyage with truck camper and no problems whatsoever.
sorry for the long 1st question. i am hoping someone might steer me in the right direction. Thanks in advance.
bernard

 

[B.G. Smith]

Don't think there is a return on either end? Could be the master cylinder it the foot pedal is not completely returning when brakes are released. bg

 

[BernardMcPhillips]

hi BG
would that occur on just the rears. read somewhere there is no proportioning valve on 4 wheel abs. i checked the foot pedal and it seems okay. but since the problem is not occuring it's hard to determine. do you know if there is a proportioning valve on this one?
thanks, bernard

 

[B.G. Smith]

I don't know about the proportioning valve, there has to be one or something that takes its place, other wise there would be no point in having the two part master cylinder. Master cyl. has two reservoirs and two pistons, one piston/reservoir server the front brakes, the other does the rear. If one piston fails something has to block off that set of brakes so you will still have some brakes. You would think that if the piston is not comuing back far enough to release the rear brakes that it would also affect the front brakes.
bg

 

[BernardMcPhillips]

rear breaks dragging. Problem solved

Hi there
Sorry it took so long. Got real busy.
I figured out the problem.
I knew that it had to be something affecting both rear brakes. When i was looking for the feed line going into the splitter block at the axle, all i could see and feel were the two going off to each brake and a rubber hose, later identified as tge vent for the differential. I was laying in front of the axle, so couldn't quite see the feed line. After talking with my buddy, i went back down and approached from the rear of the axle. Sure enough, i could see the hose coming out toward the rear and swooping up to the chassis. Not only that, i had recently installed a helwig bigwig anti-sway bar for my truck camper and the bracket i installed had rotated ever so slightly and the pointy flange was pressing just enough into the rubber hose. It was enough to allow brake fluid in under pressure but also just enough to not let it out again. (At least until the fluid would finally release)The test i had done with it jacked up and in gear confirmed this, was to step on the brakes, which would result in the wheels freezing up for about 5-10 seconds. Enough time to run out and video the phenomena. Then the wheels would chatter and slowly release to spun freely.
Anyways, thanks to those of you who helped.
Bernard