Ok guys & gals, I'm going to try posing a bunch of questions (over time) and see if anyone answers. I have a 1935 HP 18-27 on full steel that's been sitting in my shop for the past five years, I've decided to get after it with haste in the hopes of being able to drive it around by spring 2009. Has anyone out there worked on one of these before? It have it taken apart in the shop and am in the process of cleaning everything up before re-assembly. I found a full gaskets set with 0-rings from olsons gaskets that I hope to order in the next few days. The tractor was pretty clean and has come apart really easy with no stuck or busted bolts. The only thing I could find wrong with the motor was excessive carbon build-up on top of the pistons, and throughout the head. I've cleaned that all off now. My first question is, would you go through the the trouble of replacing the o-rings on the sleves if you have no reason to suspect they are bad? Do they deteriate (sp) with age, or are they best left alone? The sleves are in great shape with no scoring or top rim, if that makes any difference.