Going down the highway today, I lost power steering. I pulled over, and found coolant all over the ground, and a serpentine belt that wasn't on. The pulley for the water pump was very loose, and I'm assuming that's my problem. I was able to get it towed to a parking lot, and a ride home (70 miles).

Tomorrow I'll drive out there to try to replace it... how bad of a repair is this? Any tips or tricks?

EDIT: Also, what rotation will a 1996 4.0L HO Jeep take? Clockwise? Counter Clockwise? Opposite Crankshaft?

Just a theory, Your water pump started leaking at the shaft, the slop on the shaft and the leaking coolant caused the belt to jump off. All of this probably happened very quickly so I doubt you overheated.

Take with you, a new water pump, coolant, belt. Be prepared to replace radiator hoses in case one of them was leaking instead of the water pump.

Take the drive back very slow until you are sure you are not having overheating issues, refill your coolant bottles with water as soon as possible.

I'm finishing a water pump replacement today. I second the previous post. Also take a new water pump gasket with you, and some sealant if possible. The most difficult thing about this job (for me anyway) was removing the pulley from the front of the water pump. I needed a pair of vise grips to lock the pulley in place so I could loosen the bolts which attach it to the pump.

It was my first water pump replacement, and didn't find it that difficult.

would you recommend going at it from the top of the engine, or from underneath?

Everything can be done from the top except draining the radiator. I had to replace mine 200 miles from road in an Autozone parking lot. Had to limp 20 miles with the WP seal leaking badly. Refilled the coolant tank from every stream and puddle we passed near.

Make sure you have all the tools you need to remove the water pump, PS pump, fans, and shrouds. You will need some teflon tape for the heater hose fitting I think. Bring other emergency supplies just in case (tape, wire ties, chistel, hammer, hacksaw blade... Nothing worse than a stuck bolt sending you back for more tools.

BTW : Good luck. I hope that it goes well!

Thanks for the help and advice, it went smoothly.

IIRC, one or more of the pump bolts enter a water jacket and need thread sealer. It's always best to use rtv sealer vs teflon tape in aluminum. Teflon tape is thick and could/can possibly cause aluminum to split when the fitting is screwed in. Don't over-tighten into aluminum.