Rear drums

[Larue]

I have a '92 STX 4x4. I bought it used several months ago and don't know the service history. I'm having an issue with my rear drums. If I hit the brakes hard at any speed they lock up. It feels like they are the rear. I only say this because after the hard stop, and I continue driving there is a noticable drag in getting it going. It feels as though the parking brake was left on. I gave the brakes on all four corners the works, because when I started to take things apart brake parts started to fall off. New calipers/wheel cylinders, pads/shoes, discs/drums resurfaced, front hoses. I flushed all the lines while I was at it.

I just took it out for a test spin and I'm still having the problem. It's not as bad. Before I would have to rock the truck back and forth before they freed up. Now they just drag for a few seconds. My question would be: could this be a master cylinder problem? It's about the only thing I havn't changed out. My truck has no ABS.

EDIT: Forgot to mention while I was bleeding them the front spouts pumped good. When I tried to bleed the rear they would just trickle. Is this normal for ranger drums?

Thanks