This is my attempt at a write up for On Board Air for my ’90 4.2 without A/C with a serpentine belt. I haven’t seen any other write ups for this setup.
I picked up a York 209 from a guy on craigslist for $25. I used a lot of different write ups from the net to break it down, clean it up etc. so I’m not gonna get into all that. I used a gasket kit from Napa for the rebuild part# 207120, the kit has gaskets for the 206, 209, & 210.
Stock Bracket on the 4.2 without air and serp. belt.
And without the idler.
I thought I’d be able to fab up my own bracket, but quickly realized it was going to be way more work than I was willing to do. So I called Kilby Enterprises. Then I e-mailed them but I never got a response back from them. They don’t offer a kit for the 4.2 with serp. on their site and apparently don't offer help if you're not gonna drop alot of money. I did find somewhere on their site that showed using an A/C bracket from a CJ. So, I decided they didn’t want my money
and called J&W Jeep in Antelope CA. I went down a picked up the bracket for $50. I don’t know if this number would help anyone finding the bracket but it has a cast number of 3237579.
Here’s the bracket as I got it.
I bought a new 6 groove clutch from a seller that sells compressors, cluthes and what not for big rigs on eBay for $61 to the door. Unfortunately I forgot his name and it’s not in my eBay profile because I bought it direct.
On the York I left the incoming line the same as it came.
On the outlet side I cut the nipple off and tapped out the head to ¼” NPT.
Then used a compression fitting and connected a five foot section of copper tubing, that then got ran into the filter and check valve with a leader hose from there into the manifold.