I recently ordered a Rolair JC10 from Sean at the Tool Nut See More Here
and I'm currently very happy with it's performance.
I had my Thomas T-635HT for 2-3 years and the noise level always bothered me and the output did somewhat but more and more recently it had become frustrating. So since I had a replacement unit I decided to take the little Thomas apart to see what made it tick, or not. The Thomas is a lubeless design and uses a couple of reed valves (flappers), a wobble single piece piston/Connecting Rod, Coated Cylinder, and what appears to be a graphite coated piston ring seal. So in opening it up I was pretty shocked to see the damage the cylinder has suffered over time.
Pictures of Old Cylinder
Piston and Ring Seal with head and cylinder removed
Rebuild kit that came in the mail last night. I bought two rebuild kits at Grainger and they were an unbelievable $15 each! They are now showing discontinued on their website Grainger Link
Most of the kits were closer to $150 so I'm not sure how I lucked out on this.
Contents and Instructions
After removing the fan cover and fan, you need to loosen the screw holding the rod to the bearing and the screw holding the crankshaft/flywheel to the motor shaft.
Here's the crankshaft / bearing
Once removed it's just a matter of twisting and lifting the piston and rod from the assembly.
Here's what a new piston looks like and with the unit almost fully assembled.
Ok the rest is just changing out the reed valves that are held on with a single screw each and putting the valve block and head back on. This complete rebuild took me about 30 minutes to complete. I made a video of the unit pumping up from empty to shut off prior to dis-assembly and it took about 1 min. 30 sec., after the rebuild the first start up without allowing for break in was just about 1 min. A huge difference for sure and it was also quieter when running. Still too loud for my taste but better none the less. I didn't do a cycle test before dis-assembly but it's now less than 14 seconds from the time it kicks on to pump up and shut off. Sorry I didn't really gather much more data that that but if you have a similar unit with moderate to heavy use you may want to check it out. Since they used o rings for sealing, taking the head off for inspection doesn't cause any parts damage that would then need to be replaced. Let me know if you have any questions.