Just as the title says, my buddy's rear passenger drum went out (from lack of maintenance) on his 89 RS, and now his front driver side disc brake (which has a new caliper/rotor/pad) begins to lock up after 10 minutes on the road. What could cause this?

The front caliper was replaced after locking up about 5 months ago, and has operated fine since. Should he just replace the whole brake system?

 

Okay, maybe this is a dumb question, does his rear brakes work now?

If he is driving around with just front breaks I'd imagine it's more heat than they can handle. I could explain vapor lock but a search would do just as much.

Ben

 

Well, I suppose a full explanation is in line.

We are on the road a few days back, and he's taking off from a red light. The car hesitates like something is stuck, and then you hear this terrible crunching noise from the rear passenger drum. The rest of the day you can hear whatever was left of the shoes kinda bouncing around in the drum. It still will work to stop the car, it just MOANS really loud from that side, and now the front driver side disc brake starts to act up after 10 minutes or so of driving (especially when heavy breaking is involved). I can't do drum brakes, and niether can he, so he got some estimates on repair, he's just bugging me to find out if he should replace the whole system, or just this drum. Not to worry, he's not driving it for now.

He's got a big budget for 383/TH-350 and whatnot, and is planning on ditching the stock rear axle and drum brakes for a 4th gen rear end anyways, and is only looking for something to temporarily hold up for 3-4 months or so.

 

Drum brakes are much more complicated then disks. I wouldn't try to work on them without a service manual.
More than likely you got a defective shoe and the brake material came off the shoe. It depends on where the material came off, but it sounds like you will probably have to replace the the pass side drum. In addition I would get a new set of shoes and have the driver's side drum turned. Finally I would check the condition of your brake fluid, if it is very dark and smells burned it will not be able to handle very much heat and can cause your brake to bind. Brakes are pretty important and I've seen 3-4 months turn into a year many times. Good luck.

Ben

 

Just FYI, contaminated brake fluid will do a number on all the rubber seals in the entire system if given enough time. If the fluid looks like crap and leaves a dark residue on the MC reservoir, that is likely a contributing factor, if not the entire source of the failures.

Unfortunately, the only way to really fix things once you get to that point is to replace EVERY rubber part in the system -- i.e. rebuild the calipers, master & rear cylinders, along with a complete fluid flush.

IMHO, the best solution is to prevent it from happening in the first place, by flushing the brake fluid on a regular basis.

 

Instead of guessing about what has broken inside the drum why hasn't he actually removed the drum and see what has broken?

 

He said he didn't feel comfortable taking it apart.
Maybe he doesn't know what a bad drum looks like? Or maybe he doesn't know what the parts are called? I have no idea what he knows.
I just figured I'd give him some basic info, with my description he could talk to a shop and know if he was getting ripped off or not.
I'm sure he'll ask a couple more q's. just tryin to give him a place to start.