Hello! I have a 97 B3500 on which I have TPMS sensors installed that can read temps. I am having a problem with what I believe to be a sticking right rear brake. I just got back from a trip where I was having trouble with the right rear temp reading skyrocking on the tpms. It would get up to 30 degrees hotter than the other side and then start vibrating very badly until I stop for cool down. This has been an ongoing issue for a little while but has gotten much worse with this most recent trip. Last time i had this happen I removed the drum, didn't see any broken springs or anything obvious so I regreased the shoe contact points and reassembled. That obviously didn't fix it. I'm not sure what could be the problem other than an internally corroded wheel cylinder. The parking brake seems to move freely and it will exhibit the heating up problem even without ever engaging the parking brake. It would go from being fine to not fine.....so I've eliminated the parking brake from being a concern. One note though, the self adjuster on that side is missing some teeth. It seems to me that would cause it to be too loose rather than too tight. I'm stumped. Also, how can I determine if the bearing behind that hub was damaged or not from the heat? I don't feel any lateral movement in it, just in and out a tiny bit
...which I believe to be normal. One other thing, when I spin the rear hubs without the drums I feel and hear clicking. Is that just normal noise from the diff with the van trans being in park? Thanks to all who read all this!

 

What's happening is, the drum is getting hot, and warping. That's where your vibration is coming from. The shoes may be adjusted to tight, or the self-adjuster might be too enthusiastic..... Usually....... pulling it all apart, cleaning everything good, and putting some grease on the self-adjuster will fix it.... at least, for a while.

 

Thanks HeyYou. I will replace the wheel cylinders just in case but if the cylinder was corroded wouldn't i most likely see signs of rust on it or it would be leaking? Also, any way to verify the bearing is ok or is that highly unlikely?

 

If the bearing were bad, you would hear it.

Wheel cylinder, all the moving parts are on the inside... so, just lookin' at it, unless it is obviously leaking, you won't see anything. Replacing it is a sure way to remove it from the equation.

 

If the shoes are adjusted properly and all the hardware is working correctly, I'd say you have a little bit of gooky stuff (<----------fancy technical term) in the wheel cylinder. The cylinder may be trying to stick and when you release the pedal, it doesn't release all the way.

 

Okay, my turn... Before you touch the self-adjuster, lug nuts or anything else. Elevate the wheel and put the tranny in neutral (chock a tire, if you feel it to be necessary). Rotate the tire/wheel by hand, naturally you're going to feel for drag, but more importantly, is the drag uneven (indicating a warped drum)? My guess is a warped drum, exacerbated by heat.
The warped drum will allow the adjuster to adjust to the loose position, which will make the setting too tight for the tight position.

 

No, that is not a normal sound. A clicking noise, especially if heard only every other revolution of the wheel, is usually a sign of a bad wheel bearing.

 

Thanks to everyone for your responses. Good advice!! I only hear that clicking sound when the van is in park. In neutral when spinning the wheel all I hear is the rotating driveshaft so I'm thinking thats just the sound of the open diff with the wheels rotating in opposite directions. I don't hear any noise from the bearing location behind the hub. All of my new parts arrive tomorrow and hopefully replacing everything solves this issue.

 

Okay, I'm surprised that it wasn't the drum dragging. Is it the kind of vibration you'd feel when the tread is separating internally from the tire? If the tire is suspect, you could move it to the other side to see if the vibration follows. Obv, you'd want to look for visible signs first.

 

I replaced the cylinder, drum, shoes and all the springs on both sides. I had a problem on one side where I broke the retaining clip for the parking brake and had to fabricate something for that. We drove it 6 hours to southern Georgia and 6 hours back and had no problems at all. So I believe it is resolved. What I dont know and may never know is exactly why that brake was dragging. The cylinder did show signs it may have leaked slightly internally and had some dirt in there. It wasnt corroded but I suppose it could've caused it to stick. Or it was just the parking brake linkage binding up a little. Thanks to all who commented with ideas and assistance.