Here's what I did to rebuild my compressor and air dryer on my Hitachi air compressor
Here's everything I ordered:
Piston ring rebuild kit from eBay, seller is x8rltd
captive nuts (comes in bag of 5 from dealer, these fall apart when removing due to corrosion)
RYH500170
mounting bolts
FS108256
VUB 504700 Air Dryer (not very easy to find as a stand alone part as LR has discontinued this part, so rebuild with desiccant and such) make sure you get a kit that has a new metal dryer cover as these usually develop a small hair line crack that causes leakage. Or you can epoxy your current cover to seal any cracks.
JPO500010 kit compressor, this has gaskets, springs, and new screws for your compressor.
Relay YWB 500220
I needed a new compressor bracket too as mine was badly corroded.
After all of this it runs like a champ, very happy now but was a pain in the ******** to do. If you're having problems with your valve blocks you may need to replace them. Pull the relay and let your truck sit overnight and see if the front or rear dropped telling you where to focus.
I hope this helps, there are plenty of posts online about what you're about to do.
