'91 KDX250 Rear Breaks Grab/Lock

I ride a '91 KDX250 and my only complaint is that the rear brakes are extremely touchy and lock-up quickly, often stalling the engine (despite the heavy flywheel weight of the 250). Usually it is an issue mostly on long downhills with loose traction, but recently I tapped them on a slight uphill with some slick clay and the instant the breaks started catching, they immediately locked and stalled the engine.

I've searched the FAQ and read all the Search hits for Brakes on this forum...but I've yet to find a conclusive solution to this problem. Below I'll pull together most of the suggestions I've seen elsewhere and pose some questions. Please let me know which of the following suggestions you would try in order...

-> sand the pads
-> spray brake cleaner on the pads (may be contaminated)
-> replace the pads (with softer pads)
-> replace brake pins (scratched, damaged, corroded) with aftermarket pins. (and be careful not to strip or break during removal as many threads discuss).
-> bleed the lines using the many known methods
-> replace the brake fluid with a higher quality DOT 3/4 fluid, but not DOT 5 because it doesn't mix well
-> replace the caliper
-> Is there a complete swap option (KX, later model KDX, other brand/make, or aftermarket) that will upgrade to a better peforming brake (perhaps later technology)


Please order these steps to try to remendy this specific problem and propose any new ones or other inputs. If anyone successfully solved this issue, please tell what did the trick!

I am headed to the Hatfield-McCoy trails soon and don't want to tackle those hills without a fix!

Thanks!

Pretty much from the get-go, right off of the trailer. You press down on the rear brake lever and there is no gradual slowing, it just seizes and locks up until you let go of it. It doesn't stick on or anything, it releases just as quick as you let up.

It spins freely on the stand, that is how we oil our chains, one of us sprays while the other tips the bike up on the kickstand and spins the wheel.

The pads were changed before last riding season, < 50 hrs of trail riding (not racing) total on them. The bolts were checked and the lines bled at that time also, but this is a condition that the bike has had even just after the pads were changed and has not changed noticeably since. I started riding the bike after that change, but the person that rode it before said the bike has always done it.