2nd Gen Non-Engine/Transmission Drum brakes locked up!

[CFinley]

My uncle has a 99 model cab and chassis work truck. It has about 300,000 miles on it. He was pulling a 20ft travel trailer in to Comanche from Houston and coming into town had to get on the brakes pretty hard. The left rear drum locked up. When he finally got it loose and everything pulled apart, couldn't find anything wrong. Any ideas would be helpfull.

 

[Grizzly]

Put the rear end of the truck on jack stands. Pull off the right rear wheel and drum. Don't touch anything, but use it as a guide to rebuild the left wheel brakes. I'd go to NAPA for new parts.

 

[EKlem]

I don't know how much he uses the truck but if you let the drums on these get rusty, they will lock up pretty fast. In the summer when I only drive my truck once a week and it sits in the salty air, the rear wheels will lock up the first one or two times I try to stop.

 

[SRath]

My truck's rear brakes were set up strange when I bought it. I believe it came from the factory that way, but cannot absolutely rule out the previous owner having had them worked on.



Every drum brake assembly I have ever seen has the shorter shoe to the front of the vehicle, making the right and left sides mirror images.



This has to do with leading edge contact as they engage, I believe.



My '96 Ram had one side with the short shoe in front and the other with the short shoe in back, making them identical instead of mirror image.



I reassembled according to what I still believe is the correct "short shoe to the front" manner, and have never had any further rear brake issues once I also modified the very poor factory parking brake pedal assembly, too.



The poor drum brake engagement and wear was a separate issue and fix from the parking brake pedal problem, but now my rear brakes work evenly and smoothly and my parking brake has never again popped off on its own and the pedal stays down when I set it.





It would be interesting to know if your uncles truck had both short shoes to the front. I could understand a long shoe getting stuck or jamming more easily if it was in front.

 

[SRath]

One other thing I have seen happen in drum brakes involves a worn drum that still has a virgin, and often rusty-crusty outer edge that can, under the right circumstances, grab the edge of the brake shoe and jam it. The shoes can move around quite a bit with the spring anchors.

 

[AllianceDiesel]

you are correct the smaller shoe should go towards the front of the vehicle the main reason is its easier to push foward and slow the drum than to push backwards, so to equalize the stopping pressure they put a smaller surface area on the primary shoe (front)

 

[surfbeetle]

One other thing to mention is that with a lot heat from a hard stop, if you set the parking brake while it is still hot, it will distort your drum. Maybe that happend and a shoe was stuck. I had a hard stop and from then on, my rear brakes caused the pedal to pulsate. The last time (also after a new set of drums) that I had to stop like that, I parked the truck with the brakes off and in gear. The drums have been fine.