Compressor repair or toss?

[dj_110]

So I grabbed a pancake compressor that the neighbor was going to toss in a dumpster. He said it "kind of works". So I pull the cowl off and started to "look" at it. It will pump up to about 50 psi, then it seems to struggle to get any higher pressure. The pump continues to run, but it just seems to get hot and not really produce anymore pressure. The head gets pretty hot to the point that you don't really want to touch it. It's a little Tool shop brand pancake compressor about 1 gal. I'm not sure if it's worth pulling apart or not. Any ideas? Do you think the little chinese cylinder has had it or ?

 

[Heavymetalmechanic]

Check the outlet check valve?

 

[Fretters]

Check and clean any valves and seals which are easily accessible, and if they make no difference strip and check rings etc. For the hour or two it'll take to strip, clean and reassemble, it's worth just giving it a quick check over and fettle to see if you can get it running properly.

 

[CNGsaves]

Think of it as compressor overhaul training !

Oil-less compressor like that is perfect training for when you dive into 2 or 3 stage monster 80 gal oil-splash compressor later in life !!

Get your hands dirty on the little starter compressor with no downside for risk of failure, other than chucking it into scrap pile when you get fed up, or find fatal flaw (ie like cracked cylinder wall/head, etc). Good luck and post back with results.

 

[unslow1]

Think of it as compressor overhaul training !

Oil-less compressor like that is perfect training for when you dive into 2 or 3 stage monster 80 gal oil-splash compressor later in life !!

Get your hands dirty on the little starter compressor with no downside for risk of failure, other than chucking it into scrap pile when you get fed up, or find fatal flaw (ie like cracked cylinder wall/head, etc). Good luck and post back with results.

That is exactly how I feel about those things. I surprise myself at how many I manage to fix. Usually I just want to see how they work before I throw them out.
Recently I've fixed a LeCoultre clock, key fab and a torque wrench.

 

[MacMcMacmac]

Whenever pressure builds to a certain point then stops, I would suspect a gasket leak between the HP and lip sections. The compressor can keep up with the leak until it reaches a critical point where output equals the cross leak and no further compressed air is produced. Recompressing air is also a surefire way to generate lots of heat. Otherwise, the valves are suspect.

 

[Jere]

A family member has a small CH, and brand new. I was asked how to use it to put some air in some tires. It took a long time to add 10lbs to the tire and I gave up waiting for it to hit full pressure while not filling a tire. It was just a really wimpy compressor by design.

If you already have a compressor, I would harvest the parts you can and scrap the rest.

 

[dj_110]

Think of it as compressor overhaul training !

Oil-less compressor like that is perfect training for when you dive into 2 or 3 stage monster 80 gal oil-splash compressor later in life !!

Get your hands dirty on the little starter compressor with no downside for risk of failure, other than chucking it into scrap pile when you get fed up, or find fatal flaw (ie like cracked cylinder wall/head, etc). Good luck and post back with results.

It is actually a oil-filled model. I was surprised when I threw it on the bench to see the dipstick. Oil level is good. I was thinking the same, tear into it to see if it's something easy and if not I can strip the regulator, pressure switch, tank etc and throw the compressor part in the trash. The motor runs smooth but I'm not sure what that could be re-purposed for. I will have to tear into it and post some pictures of what I find. I really have nothing to lose, I have a craftsman 33 gal vertical so this would be just a spare for portable jobs.

I did notice last night when I posted that the top of the outside of the cylinder seems to have a film of oil (just a darker color) so I'm wondering if it's just a gasket or something. While running I couldn't feel any air leaking out though.

 

[dj_110]

So here is the little devil! I pulled the head off the cylinder tonight. I didn't see anything awry in there. I'm assuming that the 2 small rectangular pieces are the "valves" they look like shim stock to me. I wiped them off since there was some crud on them. I also wiped off the head and top of the cylinder. I put my hand over the cylinder and manually spun over the motor. I could get a pretty good "pop" out of it, so it seems to have decent compression. I reassembled the head. I pulled off the "check valve" basically a plug with a spring and rubber stopper on it where the pipe goes into the tank. That seemed to be ok and not broken or stuck. I pull the small tube that feeds back to the pressure switch off and there isn't anything blocking anything anywhere. The only thing I can think of is that something is wrong with the valves in the cylinder head since when it's running it seems to blow air out of the top port of the compressor. I thought it should only **** in air there. (There is a piece of foam in the port, I assume a filter of sorts). Also there is air that blows out of the vent hole on the dipstick, not a lot of but I find that weird. Take a look at the photos below. Anyone have any thoughts?? I'm stumped, this thing seems pretty simple. I thinking valves? but really, they look like shim stock.







With head removed


The head


This is the MAX PSI It will put out now, was 50 spi yesterday before disassembly and re-assmebly.

 

[foghorn1966]

Try cleaning those valve plates again with some alcohol or brake clean, and where they seat in the head. A light buff with fine scotchbrite wouldn't hurt either. Still look kind of dirty. Suspect that's your problem.

 

[wild cowboy]

Oil filled compressors are nearly always worth repairing

Oil-less compressors need to go in the trash, where even the brand new ones belong!

 

[wild cowboy]

also, this compressor looks much nicer than what I had imagined, I do not think you want to scrap it at all, the oiled pancakes are very expensive to buy, that is a nice compressor, definitely need to fix it!

 

[dj_110]

Try cleaning those valve plates again with some alcohol or brake clean, and where they seat in the head. A light buff with fine scotchbrite wouldn't hurt either. Still look kind of dirty. Suspect that's your problem.

also, this compressor looks much nicer than what I had imagined, I do not think you want to scrap it at all, the oiled pancakes are very expensive to buy, that is a nice compressor, definitely need to fix it!

Thanks for the tips guys. I will try cleaning up the valves a little better. It doesn't make sense to me how these valves work since they are just pieces of thin metal. I thought they would have been something more to them. The compressor is in pretty good shape otherwise. I have the plastic cowl off right now and that might be affecting some of the air flow from the fan too, so if I get this thing to pump up and put that back on it might help keep it cooler too.

I think these originally cost about $100 at Menards, I think they were even cheaper on sale. The previous owner said it's about 8-9 years old. But it hasn't see a whole lot of use.

 

[NicksRodz]

Hey the price was right and it looks like you are narrowing down on the issue. Plus the experience you are getting is worth it.

 

[Fretters]

Reed valves will work like **** if both they and their mating surfaces aren't spotless, or if they're weak or sprained. Most of the problems encountered are usually due to **** getting in there due to poor or nonexistent filtering on the intake.

 

[dj_110]

Alright guys. I took this thing apart again. I'm starting to think it's a lost cause. I cleaned the valves and the head as best as I could (see pics). They look really good. I took the plate off between the head and the cylinder to get a good look at the cylinder. I think it looks ok with the naked eye, but after looking at my pictures there are a few vertical "scratches". I can't feel them with a finger nail so that are very tiny and I don't think that's enough hurt anything. Any thoughts on that? Also, once I re assembled I can only get just over 50-55 psi and then it just pumps and pumps... I'm thinking that the cylinder is toast.

Here are the valves after cleaning. They feel really smooth, what you can see in the pictures is like stained color on them.


Here is the cylinder. You can see some cross hatching yet.


Here is the bottom of the head after cleaning.

 

[wild cowboy]

just to eliminate a couple of possibilities, get a voltmeter and insure that the full 120V is getting to the motor!

also change the oil and use a good quality synthetic like you would use for a car, in one of the following grades (any of these are fine) 5W-20, 5W-30, 0W-20, 0W-30

 

[The Cobbler]

just to be sure there isn't a leak somewhere. hook up another compressor to it ( after the head) and see if the unit holds air.
Reason I say this, I have a small senco 1010 compressor we use for small trim jobs. It started to only build about 50 psi one day. couldn't figure out why as it always built 120 before. turns out their was a small crack & thus a leak on the unloader line. couldn't here it with the compressor running, and when it was shut off, the unloader and check valve did their thing so there was no leak. the crack was allowing the compressor to build 50 psi but then the leak was equal to the output. ( Make sense?)

 

[Fretters]

It's worth a shot just flipping those reeds over and seeing if that makes a difference. As mentioned above, could be a slight leak. When it gets to the pressure where it stalls, turn the compressor off and stick your ear next to the intake and see if you can hear air escaping from there. I have an old IR compressor which has a slight leak from there due to the reed.

I'd also pop some kerosene down the bore and let it leak down, (change the oil afterwards, obviously), just incase the rings are a bit sticky. Either that or whip the piston out and check the rings.