Can't disconnect the piston arm on a Craftsman air compressor

That model number only shows in this post. I don't see how a compressor can be 'oil-less', the friction and pressure is enormous!

https://www.google.com/search?q=6.5+HP+oil-less+60-GAL+MOTOR+%22K56A28B23%22

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Some of the craftsmen compressors have pistons that are coated on the top of the dome. Once the coating wears off, they have severe loud piston slap. If you continue to run it the way it is, it will snap the connecting rod in half or break the piston and possibly the cylinder.

A piston in any engine should be around 100 psi I would guess. A Chevy 350 used to be around 150 psi. An air compressor that only pumps enough air to reach 20psi is obviously too low on compression. Nailers and the like need 80 or more psi. The intake valves may be shot, the unloader might be stuck or piston rings are worn.

Take the exhaust tube from the compressor and run it for a moment or two with your finger over the exhaust port--it should try to blow your finger away. If no pressure, remove the cylinder head from the compressor and inspect the valves in the head assembly. Reeds or discs, if any are cracked or broken, replace same from: Seardpartsdirect.com Make sure the valve seats are in good condition--if not, you may need to replace the cylinder head from the same source. Make sure the piston(s) move up and down when turning the compressor pulley. Inspect the piston top(s) and cylinder wall(s) for excess wear or other damage. The only other problem would be a hissing leak from some tank component. Hope this helps!

Try emptying the tanks completely. There should be a bleeder valve for each tank. Sometimes after sitting for a while with pressure, the compressor won't have enough power to start. If you get the same response with empty tanks, there is a problem with the pump pistons.

Dan

GO TO SEARSPARTSDIRECT ENTER THE MODEL NUMBER AND IT WILL SHOW IT ALL TO YA LET ME KNOW IF THIS HELPS YOU

hi mate if the pump is connected then it doesnt have a belt its direct drive and if the motor is seperate from the pump unit then it belt driven i dont understand as the picture is a direct drive (no belt)

you just replace the belt, timing is not nessescary.

this is probably an "oilless" compressor, it has "piston" with a thin ring of leatherlike material acting as a piston ring, the "cylinder" is an aluminum sleeve - what usually happens is the cylinder gets scratched from dirt or just wear or the leather ring deteriorates, that's why it will go only so far - the only fix for this is to replace the cylinder and the piston

check your popoff valve first. it is the valve with the ring hanging on it. You will hear the air rushing.

If you don't hear any air rushing, you may have fried the piston rings or broke/chipped the piston(not your fault)..especially with oiless compressors