Just got back from the junkyard. Needed a double pulley for the steering pump. I knew right where one was, but of course they were closing in 15 minutes, then I discovered I didn't take enuff tools/the right tools along, and couldn't get it anyway. Couldn't get the socket wrench between the puller and the radiator, and forgot a wrench to hold the body of the puller. I hate when that happens! I'll be going back in the morning.
The one we are running has two different diameters, and we are using the smaller one because that's the one that lined up. We also thought that would be good in that it would have the pump spinning faster at the low engine speeds of rock crawling. Made sense, but...the smaller diameter pulley apparently isn't giving enuff belt contact, and with the high output pump, under load, the belt slips.
We were advised it would be good to run a double belt even, but the only way to do that would be to lose the double belt on the alternator and A/C compressor. Don't know what produces more of a load, the compressor, or the steering pump, so I'm not sure what side to put the double on. We have hydroboost brakes also so the pump gets quite a load.