The valves are nothing more than reed valves and are part of the head plate assembly. Getting to them is no problem after you've discharged the system. It's unnecessary to remove the compressor to remove them. If you remove the hoses, make note of the location of the suction and discharge ports, right or left. Remove the head bolts and the head should come off fairly easily but you can TAP on the side of the head if needed...don't BEAT! There'll be a gasket between the head and valve plate. If the valve is leaking, take a look at the top of the piston and cylinder walls after you've removed it. If they're skined up or beat up, look for a replacement compressor. Check the valves and see if there's some crud sticking in there or they're broken. If ok, they valves can be cleaned and reused. Something like aeresol electrical contact cleaner works good and it's much gentler than brake cleaner. That stuff will eat plastic! Don't ask me how I know. Replacement gaskets and parts should be available at most any parts store. Be sure to clean off any pieces of gasket sticking to things before reassemble. Also lube everything with refrigerant oil before assembly. Don't try to cut corners and use motor oil, gear lube, driveway sealer, roofing tar or the like. The shaft seal can be replaced without removing the compressor or hoses. Again, have the system discharged, but if the seal is leaking chances are it's already discharged or else you wouldn't be replacing it in the first place! To remove the clutch and pulley, first remove the little bolt in the center. Then thread a NC thread bolt into the larger surrounding hole and tighten it. (I'll have to check, but it MAY be a 5/8", been too long.) The shaft is tapered and keyed and like a Stude rear drum, it'll pop off suddenly. Clean off all the crud and dirt and remove the platte surrounding the shaft being careful not to scratch the surfaces. Hold your had under it when you do remove it because sometimes the seal will come off with it, pop off and be gone or stay in the hole. It can ususlly be removed with small screwdrivers, picks or the like (don't scratch the shaft!). It'll be about the diameter of a half dollar and maybe 1/2 inch thick with two halves and a spring between the two. Clean things up and if the shaft is rouch, use crocus cloth to polish up the shaft, lube the new seal and shaft with refrigerant oil and replace, making sure the carbon face of the seal faces the outside so it will contact the seal plate you removed earlier. Reassemble and you're set check the oil level. There's a little bolt on either side of the compressor located near the center. Remove it and make a little dipstick. It the compressor is laying on its side, sometimes a small wooden dowel 3/16-1/4" will work or use a piece of dark colored wire. Insert it until it hits bottom and measure the level. It should be between 7/8" and 1-5/8". If the pump stands up, bend a curve in a piece of wire and curve it down through the hole to the bottom. The oil level should be between 7/8" and 1-3/8". If you need oil, use that bottle of refrigerant oil you bought earlier, remember? One other thing to remember is if you're changing from R12 to C134 refrigerant, you'll want to drain and refill the compressor with the appropriate oil. Sometimes the old and new oils don't mix too well. The auto parts store should be able to fix you up with the right one.