During braking the left rear wheel locks up for a split second and the starts rolling again. Noticed brake drum was and had been extremely hot. I pulled drums off and found LR emergency brake had not released, took the shoes down to metal. Did brake job on both rear wheels, replaced seized up ebrake cable and check the brake cylinders for leakage, all looked good. Reassembled and adjusted brakes. LR wheel still locks up momentarily while braking???????

 

Also had to buy new brake drum for left rear wheel

 

See the following link. Things mentioned are bad proportioning valve, swollen rubber brake lines, & faulty master cylinder.:https://www.ford-trucks.com/forums/8...ocking-up.html

 

Did you rebuild or replace the brake cylinders?

Could be binding of one of the plungers within the cylinder. Can be caused by water in the line (brake fluid is hygroscopic), causing rust. Rebuild kits are cheap on RockAuto ($8/wheel). If not too bad, some emory cloth will clean it up. Then just add the new seals and boots.

 

Many people don't know that there is a leading and trailing shoe with these drums and the leading shoe has a little less material on it. If you don't look closely you can miss this and if both trailing shoes end up on one side that wheel will be prone to lockups.

 

Thx for the replies. I think I'm going to buy new wheel cylinder and other internal components, replace all. I know I have the right brake shoes in the right locations. Hopefully this fixes issue. Don't usually just start throwing parts at a problem but in this instance if it works it will be a cheap fix. Thanks again.

 

Ok so I installed my $35 worth of new parts, along with new shoes and drum the only thing that's not new is the backing plate. LR wheel still locks up momentarily? Could it be the ABS hydraulic unit? The ABS has never worked on this pickup since I've owned it but just recently noticed the wheel locking up.

 

Just tried something on this old binder, unplugged the electrical connection to the ABS hydraulic unit and took it for a test drive. With that disconnected it does a fine job of flat out locking up both rear wheels when braking, plugged wire back in and I'm back to LR locking up just long enough to chirp the tire. Maybe this is a "well DUH" to some of you out there but I ran out of ideas a long time ago!!

 

Anybody???
Went to town last night and when I got home it was dark out, as soon as I stepped out of the cab I seen smoke boiling up off of the brake that has been giving me so much hell!?!?!?!? Have not torn into it yet to see what happened inside the drum.

 

Kinda says something there... you should look into WHY the HCU is locking up that brake. I'm not sure how the anti-skid works on that truck but perhaps it has a self-test function??

 

I HIGHLY doubt it is the ABS unit since it MONITORS the rear wheels asa pair. Not individually or control them in any way