2nd Gen Non-Engine/Transmission Rear drum brake locks up

[Kalaehina]

My 96 driver side rear brake locks up if I'm not careful of how much pressure I put to the pedal. The truck has brand new cylinders on both sides, brakes have been bled, shoes look ok, drums ok, everything dry back there. Slow speeds I can make it lock up, and I've noticed it's the drivers side, at high speeds I can apply more pressure and it won't lock up. Had a scary episode today when I have to brake a little quicker then I usually would, roads were wet and I went into a slide. Any suggestions where I should look next?

 

[GAmes]

Although it seems like it should affect both sides maybe the flex hose to the rear axle. Another possibility is the ABS. Does it do it if you pull the fuse?

 

[BigPapa]

I had this issue when I had a cylinder leaking. You sure the shoes haven't had brake fluid on them?

 

[Kalaehina]

I'll give the ABS check a try. I'll double check the shoes when I look more into the drum, but I'm pretty sure they were dry. Thanks!

 

[madmac74]

How about a stuck or siezed load sensing arm near the top of the rear end ? I hear this can give excessive braking while unloaded ..

MAC

 

[Kalaehina]

Thanks I'll check that out as well.

 

[JMcCoy]

Your signature doesn't specify whether you have a 2500 or 3500. If you have a 2500, I would definitely give the proportioning valve a gander.

If not, it sounds like contaminated brake linings. You may have their own replace them again if they are saturated with brake fluid or grease. Hope you get it figured out.

 

[fest3er]

A leaking axle seal could also cause grabby brakes.

 

[Wayne M.]

Kalaehina, I don't know your level of mechanical ability, so please don't take offense, but when it comes to old tech like drum brakes, sometimes you have to go back to square one. IIRC, 2 gen trucks use a delco type setup versus a Bendix in the 1 gen. Both can be temperamental especially in dampness and after sitting. Correct in saying that the issue won't go away after the brakes have warmed up? Then go back to the basics. Make sure the shoes are arranged proper (primary/secondary) and the adjusters are on the correct sides (R/L) and that the linings are properly adjusted, and the shoes rest on the top anchor pin (that the wheel cylinders are retracting, and the parking brakes are fully released). Also yes check the load sending valve if you have one.
If all this is good, and your friction surfaces are good, you should be good. Good luck!

 

[Missouri Mule]

Did you change out the cylinders your self or have it done? Looking at my 96 service since only one side is locking up it is not rwal.
My first thought did you adjust the brakes after you put the new cylinders in?
"Other possibilities are improperly adjusted or seized parking brake cables, bent or binding shoes or support plates , or improperly assembled components. This is particularly true if only one wheel is involved."