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I just bought a '79 and everything is stock. The front passenger brake locks up under normal to hard braking...
1. Is this common?
2. What can I do to fix it?
3. A small block is in the future. What kind of brake set-up is recommended?

Well for now a normal brake job with caliper rebuild would be smart. If you are just going to tear it down and the V8 now, then I would wait incase you might do a brake swap.

I'd bleed all the brake lines and see if that helps. It's fairly quick and easy. Rebuilding the caliper or getting a new one may be a good idea if that don't work. Have fun!

If you are going to do a front brake job you might want to replace the rubber brake lines. These lines do brake down so replacing them is a good thing to do.

Dottie, how is the LUV? Did the parts I sent you work OK?

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Certified pilots, looking down on people since 1903.

Yeah, Thanks LUVRV8! She is running like a champ! And even passed inspection! She pulls a little because the rotors were different manufactuers (although new), so if any of you are thinking of putting on mismatched rotors, don't do it! Notorius Skinny, I just replaced my calipers, rotors, pads, shoes, drums, flexible brake lines on my 79. I heard from a few people about replacing the flexible brake lines. One of them was difficult to get off from the metal brake line, but came off eventually. Good luck and rock on!

Thanks for the advice. I'll start with these ideas and go from there.

Someone suggested to me that it might be the proportioning valve in the master cylinder. Could this be it or is the caliper more likely to be the source of my problem? I checked the driver's side and the piston moves when the brake is applied so it is getting fluid...proportionally or not I don't know.

Pull the calipers and clean the slides as the corrode and stick do this first.

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s

The valve you are talking about is front to back, not side to side. You can rule that out for the most part, your problem will be the caliper and/or the rubber line. Also make sure your front wheel brgs are adjusted correctly.

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Certified pilots, looking down on people since 1903.

This is pretty common on luvs that have sat for a while. My 79 used to do it pretty bad. All I had to do was take apart the caliper ann clean it up. There is a lip inside the bore, outside of the seal, that rusts up and then sticks against the piston. Clean that lip off with some light sandpaper just to knock the rust down and then put it back together. On some of mine I've had to clean up the piston too with something like a scotchbrite pad. If you are very careful in getting the boot out you might not even need the rebuild kit. The boot has a retaining ring that holds it into the caliper and just a lip that holds it into a groove on the piston.

To get the piston out, I usually just get the boot off, then slowly pump it out with the brake pedal. It makes a bit of a mess, but it works. Just try not to let the pedal go to the floor or run the master cylinder out of fluid. Get it all cleaned up, and cleaned out with brake cleaner, then wire the caliper up so the bore faces up. It will slowly fill with fluid on its own. Let the master cylinder get low, but not empty until the caliper is full. Then put the piston back when the caliper is full. If you do it right, you won't have any air in the system, and won't need to bleed anything.

Can you tell I've had to do this by myself a few times?

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good