Disc brakes grab and chatter barely moving the truck

[mtnmankev]

JB7 brakes on 83 C20.
Engine idling, in gear, let truck barely roll and tap brake pedal, seems like both front discs grab and if i go a tad faster (maybe 2 mph) they "chatter" like a fast grab and release.
I have been told it's due to rotors needing to be resurfaced, but I can't see that much out of true happening at minimal rotation.
At normal driving speeds, the brakes function just fine.
I plan on having the rotors resurfaced for general principle, but what else should I look at?
Perhaps the calipers?

 

[Blue Ox]

Perhaps the drums? Unless you've got a disc conversion it sounds more like a rear brake problem. Remember, the drums apply first, and at low pedal pressures they may be the only thing braking.

 

[mtnmankev]

It took me a while to get around to working on the truck, the real world got in my way.
Took it apart this morning, and it seems you were right, it's in the rear.
Leaking wheel cylinder and/or axle seal.
Going to replace both on both sides and have the drums turned to clean them up.
Shoes have plenty of meat left on them, so some brake cleaner should make them good again.
Springs and hardware seem okay.
If all goes well, I will never again have to remove the rear drums.
Those 13 inchers have a ton of gravity in them.

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[CSFJ]

If the leak has been occurring for any length of time, the friction material on the shoes will be soaked through. Brake clean will not draw it out. The shoes need to be repkaced, or you will still be plagued with noisy brakes that will not grab evenly. This can cause hot spotting on the drums and cause them to warp again. Do yourself a favor, and replace the shoes and springs too.

 

[mtnmankev]

Thanks for the advice !!
I got new shoes and springs today at NAPA.
May as well do it right, the truck is in excellent shape, and I learned about a truck like mine (different color) that sold for nine grand in less than two days of the ad getting posted locally, so the truck is definitely worth doing it right.
I was shocked to hear that truck sold for $9,000 there was nothing special about it.
I guess our old pickups are going up in value now.

 

[mtnmankev]

PROBLEM CURED !!!!!!!!!
Doing the rear brakes did the trick, thanks for the suggestion
Replaced wheel cylinders, shoes, springs and had drums turned.
Also replaced the axle seals while I was there so i will never have to worry about them.