I have a 2 year old craftsman air compressor, model 919.167782 The compressor is not pumping up fast. It ran 1 hour and only pumped up to 30 lbs (and I wasn't using any air) - I replaced the entire pressure switch assemply and regulator. - I disconnected the tube from the compressor head to the check valve to see if air was being discharged from the head and it is. - It is an oilless compressor. The two pistons are working properly. - Normally the tube from the compressor head to the check valve gets hot very quickly. The tube on this compressor is only getting warm, even after 1 hour of pumping. - The check valve is not leaking to regulator since I plugged the side entry on the check valve temporarily to see if it would make a difference - it did not. - After the compressor pumped up to 30 lbs after an hour. I shut it down and came back 15 minutes later. There was no pressure loss. - The only thing left is the intake and exhaust valves in the head or the check valve going into the tank. One odd thing is the tube going from the compressor head to the tank does not get hot - only mildly warm, this suggests to me that the intake/exhaust valves are defective. There must not be alot of air coming from the compressor head or the tube would be hot. I looked at the check valve, sticking a screwdriver down inside. It is not stuck and seems to work fine. Am I on the right track to replace the intake and exhaust plate valves ? Thanks for any advice.
It could very well be the valve plate however before you order parts take a look at the cylinders. Unplug the unit, remove the cover from crank side and turn the compressor by hand till the/a piston is at top of stroke. Examine upper cylinder for scratches /wear or failed vinyl piston ring. On oil-free compressors, dirt and grit is sucked-in from the bottom of the cylinder and causes leaks between cylinder wall and piston. If scratched, air pressure is leaking down thru cylinder wall. Failed reed valves cause a pulsation at the intake port (air seems to be pumped out the intake). If you see a model number anywhere on the pump that begins with " WL", your pump is made by Campbell Hausfeld. Parts can be ordered from www.chpower.com. other-wise order parts from sears parts. Cylinder kits are around $40. Good Luck on the repair and email if you have questions.
SOURCE: craftsman pro mod# 919167770 , oilless air
Check to be sure your drain valve under the tank is turned completely off first
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Had the same problem with a WL compressor - popular with many other brand names/ models and a ton of them use all the same parts.. Found tube kit needed to be replaced. Everything worked well for about one hour of run time after original fix....Same symptoms again but, not the tube kit second time around.
Found a new pump/motor assembly for $10 over the cost of a rebuild. Yes, about $50 under the most houses selling parts. Installed new assembly, tube kit and check valve. Everything seems to be working fine now.
Opened the old motor and it appears the rings are bad and the cylinder is scored. Sent the old motor to recycle after pricing all the parts including; gaskets, seals, and cylinder kit. My list did not even include a new belt, piston or anything else. I saved the old tube. The old check valve had a ton of junk stuck in it – glad I replaced it!
Hope this helps.
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