I got this info from a member on another site and it worked. Maybe it will help other members out as well.
You have a classic case of the air gap in your compressor having worn too wide.
Try this to test:
Turn on the A/C and run it until the clutch won't re-engage. Be REAL CAREFUL now! Take a plastic screwdriver handle and "tap" the end of the (not spinning) clutch. Does it immediately engage and operate normally until it next cycles off, and then won't re-engage on its own?
Get out your feeler gauges, or your calibrated eyeballs, and determine that the air gap is about .050" to .060" (fifty or sixty thousandths). That's too much! It's supposed to be around .030. But wait! There's no need to replace the compressor and have to re-charge the system. There's a "dirt-cheap" fix!
See the little bolt right in the middle of the compressor shaft? Take it out. You won't be letting any Freon out. Pull the clutch plate straight out. There is one or more "shims" that look like small washers in there, either on the end of the shaft or down in the hole that fits on the shaft. Take off about .030" worth of them and reassemble. Go ahead, use a little blue (NOT green!) Loctite on the bolt as insurance.
Make sure you now have at least .025" of gap. Start the engine and check to insure your problem is gone.
That's all there is to it.