Rear drum drag

[TeamEstep]

Well, it's been a drag trying to resolve this problem, ha ha. I have a '71 LWB that the drums have a slight drag. I had converted the manual brakes to boosted and while I had everything apart, I also replaced the calipers, pads, cylinders, shoes, springs, all brake hoses, CPP proportioning valve and some of the brake lines. I blench bled the new master cylinder before installation, and bled the brake lines starting at the furthest wheel. The brakes work fantastic but the back drums have a slight drag. Sometimes worse than others.
Here is what I have done/investigated so far:
1)I took the brakes back apart and took my flapper wheel to the contact points on the backing plate and cleaned and smoothed them, then added a thin film of high temp grease to those surfaces. I also cleaned and put a small amount of grease on all pivot surfaces.
2) I made sure the primary shoe (shorter liner) was forward.
3) I made sure there was a wavy washer on the e-brake lever. (Brake cable is not currently connected to the pedal.)
4) I made sure the adjuster was not too tight (adjusted until tight then backed off about 3/4 turn. Wheel turned freely).
5) I made sure the correct hold down springs were on the right shoe.
6) The brake pedal has free play at the top of the stroke so shouldn't be pre-loading.
7) The master cylinder/booster came as a kit so the rod length between the master cylinder and booster should be correct.
7) I checked the level of brake fluid in the master cylinder and it is about 1/2" below the top so there should be enough room for return fluid.
The symptoms seem to indicate a bad brake hose but I had replace all of them.
I did happen to run the master cylinder out of fluid while bleeding the back but refilled it and re-bled the back.
Could air somewhere in the system cause this symptom? Seems like it gets bad if I get on the brakes hard. If I keep brake pressures light, it doesn't seem to get bound up. Sometimes if I give it a light tap or two on the brake pedal it seems to free up but could be my imagination. It does not seem to be temp related as the brakes are sometimes dragging when I first drive it.

Any help is appreciated. Thanks!

[davepl]

Anything change the tension on the e-brake cable? I've had that and the star adjuster wheel both cause it, but that's it for me.

I've -heard- that new shoes can be fat and need to be turned down slightly sometimes, but not run into it myself.

[TeamEstep]

Thanks davepl
I haven't cycled the e-brake and don't think there is anything that could be moving it. I did check to see if the e-brake mechanism in the drum was moving freely.
Also, since I was able to set up the adjuster so that the wheel moves freely, I don't think the shoes are too fat.
The curious part is that it is in both rear brakes. I would think that if it was something I did wrong with one of the wheels, it would be only one wheel and not happening to both.
I'm stumped!

[Kennuck]

New brake shoes when set up properly will have slight drag on them when you turn the wheel. It may be harder to turn in some spots than others but they will bed in eventually.

[cdowns]

did you physically measure the master rod length and clearances or just figured they'd give you good stuff

[Wrenchbender Ret]

A little drag is normal on that type of brakes. The shoes float on the anchors. Make sure the e-brake cable is not adjusted too tight. It can pull the shoes off the anchor pins. If they are working normal & not getting too hot don't worry about it.

[TeamEstep]

Wrenchbender, you got me thinking about the e-brake adjustment. I had ignored it because the previous owner had disconnected the pedal. After further investigation, it turns out that the cables were stuck part way deployed. That would explain why the drums were shot and the shoes were worn down to the rivets. I loosened up the cable and made sure the levers in the drum were retracted. Works great now.
Thanks!
Now I need to replace some e-brake cables and get that back to normal.

[Kennuck]

Now you have to re-adjust your star wheels so there is a slight drag on the shoes for proper adjustment.

[TeamEstep]

Thanks, I did that too. For the first time since I bought the truck a few months ago, the brakes feel normal. I realize now that before I upgraded the brakes, I was only operating on front discs only with manual pedal. Panic stops were sketchy at best. Now everything is boosted and operating normally.
This forum is great and I appreciate everyone's help. Sometimes you can't see the forest for the trees and it helps to have others point things out that you may be overlooking.