Drum Brake Lock up

The rear brakes lock up with just the touch of the pedal when its damp, raining or I haven’t driving in a few hours.. I have rebuilt the brakes.. Still the same issue..All new parts... accept the wheel cylinder. Any Ideas???? ABS is disabled, New Fluid... I just don't know..
Thanks for any ideas....

Possibly your brake shoes have become contaminated or soaked with brake fluid.
Cleaning or sanding the shoes usually will not correct the problem.

Shoes installed correctly? Traliing shoes (rear on both sides) are the larger shoe. Or, possible the height sensing proportioning valve is out of adjustment or faulty.

Thanks for the help.. I don't think its contamination but I'll doubble check. Level / Load valve. I didn't know there was one.. I'll have to check the servive manual as to where it is, how to test and replace.. Looks like I have more work to do. Thanks

I have a similar problem. But I must press the brake pedal relatively hard. Although the amount of pressure I use should not normally lock up the rear drums. It happens under EXACTLY the same circumstances as you stated. After I drive a little bit it goes away but always comes back after it sits for a short time. I assumed initially that it was something I did when replacing the drums and shoes. So I took it to the dealer to have them inspect, clean and adjust for around $90. Dealer reported back that there was no problem. Although my rear drums are warped from one of those tire shops adjusting them too tight (not long after they were repaced). Wife drove away and noticed once she smelled them burning up. I'm pretty sure mine did it prior to that incident though and dealer performed the service after that happened. It scares me because it is likely they will lock up much easier in the snow. I would love to know if you track down a solution.
BTW, mine is a 02 Voyager 4cyl bare bones.