This will be a bit obscure for most folks, but I thought I'd post this for anyone else that may want to replace the pulley bearing in their Seiko Seiki compressor, which came on 93 245s and some 700/900 cars.

I've been listening to a whistling noise comming from the engine compartment in my 93 245 for a while and finally isolated it to the A/C compressor. The noise would always go away after the engine heated up, but was loud when the engine was cold. It was there regardless of whether the compressor was engaged and went away if the belt was removed, so I concluded it was a bad pulley bearing. The compressor is a Seiko Seiki SS-121DS5 (as opposed to the much more pleantiful Diesel Kiki on earlier 240s).

Remove the belts. The clutch gets removed via a single 5 mm allen head bolt in the middle. No puller is needed, but ensure you save the shims that either fall off or remain on the compressor shaft - they ensure the correct air gap for the clutch (between 0.3mm and 0.6mm (0.012" and 0.024")). Check the clutch and ensure the rubber bushings are OK. If not, no need to proceed any farther until you get a clutch kit, which will contain the clutch and pulley (which will have the bearing already installed). Also, look inside the compressor snout for evidence of oil, which is a sure sign the front seal is leaking, which may cause you to abort replacing the pulley bearing and get a new compressor. I've been told by an A/C shop that leaking refrigerant can dissolve the grease inside the sealed bearing and ruin the pulley bearing in short order, but that was not a problem on my car.

The pulley is held on the compressor snout by an internal circlip, so remove that first. A mirror and light help alot here. The pulley on my car came off pretty easily by using a couple of screw drivers to gently pry against the compressor ears, but if this doesn't work, get a large gear puller. You will note that the bearing is pressed into the pulley and then staked by deforming the metal around it in a number of places. Press it out, or do what I did and support the pulley between a couple of blocks of wood and drive it out with a drift. Now for the hard part - getting a replacement bearing. After alot of searching and dead ends, this is the correct part: Santech 25-B95-1102. Note that is NOT SCANTECH!. This bearing can be order from A/C part supply houses, but I recommend you go to a local supplier so you can get it properly pressed on and re-staked.

Re-assembly is straight forward and you can use a couple of C-clamps to pull the pulley back on the compressor snout. When back on, the pulley should be just clear the end of the compressor shaft. Ensure the clutch air gap is correct and if not obtain the necessary shims and you're all set!