Are the brake shoes clean? Doesn't take much axle grease from a leaking seal, or a much brake fluid from a leaking wheel cylinder to cause a wheel to lock up. I understand that you have replaced the wheel cylinder, but these days, something being new does not mean its good.
Another thought is what condition are both of the backing plates are in. The brake shoes rest against the backing plate on 3 contact pads for each shoe. Those pads need to be perfectly flat. If there is a dip in any of them, the shoe will sit in the dip and could easily cause the wheel to lock up. It wouldn't return as far as the other side of the axle, and therefore makes contact with the drum faster, or it could be on the other side and may be keeping the shoe away from fully contacting the drum and it may not be functioning at full capacity, or may not be functioning at all. If there is a dip in any of the 6 pads on either side, you can weld them up, and grind them flat again. If you find any wear, check both the front backing plates as well. Gene
Good thoughts.
Everything was cleaned mulitple times and I've found no leaks.
I've heard about the pads on the backing plates. I checked both sides on the back and I couldn't see any difference between the two but I'm not sure how much wear on the tabs would make a difference. If I can't see a difference could that still be the issue or do they have to worn to point where you can tell by looking?
With the shoes off, run your finger across each pad. If you can feel anything except a smooth flat surface, it could be your problem. Sometimes it really doesn't take much surface difference at all to cause a problem, but I have also had the pads feel and look like they have Grand Cannon grooves that don't seem to make much difference.
Does the car have self adjusting brakes? We had a customer once that lived on a one way street, they backed out of their driveway in the same direction every time they went someplace. The self adjuster on one side would tighten the brakes more then the other side, and the first few stops would cause one wheel to lock up. After a few brake applications, it was good until the next time they left home. It just happened the boss was driving by one day when they backed out of their driveway. We removed the self adjusting cable for a week, and the problem went away. After we reinstalled the adjusting cable, the problem came back. I think the boss suggested they change how they back out of the driveway. Anyway, just another possibility, since your looking for strange stuff. Gene
