I have an old model 283.150571 Craftsman 1/2HP air compressor. It's been a great little utility compressor over the years but two parts finally gave out - the piston seal and the piston sleeve. Apparently when the seal gave out, the piston started digging into the sleeve and trashed it. The piston itself and all other parts are okay.

Unfortunately since this is an old model, Sears no longer has replacement parts and a search on the internet has proved fruitless. Several months ago a friend gave me a compressor service kit, Thomas model SK-1207/80. A couple weeks ago I decided to effect the repair but quickly found out the piston and sleeve in the repair kit are larger (same stroke but larger diameter) than the piston and sleeve in my compressor. I believe the repair kit is for a 1HP compressor.

I'm confident I could adapt the larger piston and sleeve to my compressor by installing a larger bearing, (the new piston needs a larger OD crank bearing), milling out the head to accommodate the larger diameter sleeve and if necessary, drill an additional exhaust port (the kit provides new port flappers), however, I'm concerned that the larger displacement may be too much for the 1/2HP motor. What I don't want is to spend the time to do the modifications only to find out, the motor stalls out. So, my question is, does anyone know where I might find repair parts that fit my compressor, or will my proposed modification to accept the repair parts I have work?

MTR,
Thanks for the reply. You may be right about the HP. The nameplate on may compressor says 7.7 A and 640 Watts which is certainly more than 1/2HP. The side of the compressor says 1/2HP which surprises me since Craftsman is famous for using peak horsepower (a meaningless metric) in their advertising.

Anyway, I looked at the 1903 kit and it doesn't match up with compressor. There is no piston sleeve in the kit, as far as I can see, and that is one of the critical items I need. Also the head gasket in the kit shows rounded inlet and outlet chambers and mine are rectangular. My piston has a slot near the top for the leather/fiber (?) piston seal, which is the other critical part I need, but the 1903 kit does not have that seal. Except for the piston size, the kit I have is a better match for my compressor.

Unless you have another suggestion, I'm thinking I should go ahead and try my modification. The kit was free and a larger bearing will probably cost around $5, so I only have the time and effort to lose if it doesn't work.

John

MTR,
That's interesting about the sleeve and seal not being shown and they are not listed as components in the 1903 instructions. If I were selling a repair kit with a picture of what's in the kit, I'd make sure I showed all the parts especially the critical parts (e.g piston sleeve). I mean, they show the Loctite squeeze packs and those are available from most any hardware or auto parts store.

I guess I don't understand the thinking.

John