Lean me: Air compressor maintenance and repair

I found me what I thought to be a smoking hot deal on the CL for this guy:

http://www.eaglecompressor.com/newdynamic.php?name=C5160V1&Type=ALL

Brought it to the garage, bolted it to the floor, ran 240VAC across the rafters, hooked it up, and it won't build pressure past 110psi, and the shut-off is set for 125psi operating pressure (so it never turns off). It also builds pressure REALLY slow from ~100psi+, like took 10 minutes to make another 10 psi. Turning it off, no hissing noise anywhere, and holds the pressure. When running, by observing the effect of a latex glove over the intake I surmise that while the right and left cylinders are drawing air like you might expect, the center one is just puffing it around, maybe even blowing it out. And it's hot air it's blowing out.

My expert deductive skills indicate something is not quite right with this compressor. But what? Should I order this:

http://www.allpartsinc.com/ProductDesc.aspx?code=101000-165&=0&eq=&desc=101000-165-VALVEREPAIRKIT

or this?

http://www.allpartsinc.com/ProductDesc.aspx?code=101000-265&=0&eq=&desc=101000-265-RINGKIT

or neither?

Or create an ad - "hardly used air compressor - mint!" and pawn it off on some other unsuspecting sucker who thinks he's getting a smoking hot deal?

It sounds like you need the valve kit. I have done it and it is very simple and quick to do. For $37, what do you have to lose?

How does the oil look? Worst case it looks like you can do a full rebuild on the pump for under $100.

sporqster wrote: the right and left cylinders are drawing air like you might expect, the center one is just puffing it around, maybe even blowing it out. And it's hot air it's blowing out.

Leaking valve(s), loose or broken. I'd put the valve kit in it.

If you don't need to use it right now pull the head for inspection. Being that new, you might just luck out and only have a loose valve or dirt in the seat. Probably still gonna need to replace the gaskets tho. Check piston play and inspect cylinder wall while yur in there.

I'll bet that one or both of the reed valves are not working correctly. Replace them and I bet your have a good compressor that should last you years. Changing the oil can't hurt but the symptoms you describe says the valves to me.

I'd pick up both of the above parts and go through the compressor. I did the same with mine. Bought cheap, put $100 in parts in it and it makes more air than I will ever use. That's a $1000 compressor, it's worth $100 in parts unless you paid $1000 for it.

Update: ordered this , replaced valves, works like a champ!

sporqster got it working, time to thread highjack.

Any ideas on rust repair? I neglected to drain my compressor for a year. When I finally remembered a significant amount of brown water came out. How concerned should I be?

In reply to calteg:

Not very, the tank is mild steel, so they normally don't explode, just crack open on the bottom.

Not to worry normally you end up with a pin hole that you tap for a screw.....

sporqster wrote: Update: ordered this , replaced valves, works like a champ!

SWEET!!!!! I'll have to come over and try it out soon, hopefully after it warms up a bit.

Mine did something similar so I did a valve job and new gaskets. Still did it. Turns out the rings were knackered and it was busy as hell pressurizing the crank case.

Now I'm buying a new pump from HF.

I had a compressor tank that let go due to rust inside of the tank. It just started to hiss and lose pressure. No explosion! This was a Craftsman brand that was 20 years old. I ended up buying a used compressor that had very little use over it's life. I bought it only for the tank as it was one of those "oilless" types.

I cleaned out the tank with rust remover chemicals, when dry I poured in an epoxy metal primer paint. I rolled the tank around to coat the whole inside. I may do this to any new tank in the future.