Air compressor repair question

[Josh_Br]

I have a Craftsman air compressor. I've had it about eight years, and it has quit running. It has an oil-less motor, which I know are not great but I'd like to repair it if possible. I've found websites where you can buy any part for the motor, if you know which part you need. It's a 3 HP, 150 psi, 15 gallon compressor, model # 919-167241. One day when I was using it, the motor was running and started to get slower. It got slower and slower, then just stopped. Now it won't come on at all. Does anyone have any idea what part or area of the motor may be at fault?

Thanks,
Josh

 

[sandyda]

It's the pump that's oiless, not the motor.
Vent the pressure, test the elecrical outlet, plug it in, turn it on and listen closely. Does the electric motor make a straining noise? Then its likely the pump is frozen. If it makes a low moan it's haunted; try an exorcism.

 

[Lightfoot]

will the motor run with no load (unhooked from the compressor)?

 

[LEVE]

I'll agree, the pump is locking up, for what ever reason. Take a look at the Sears Parts Manual. It will show you the parts breakdown and parts numbers.

Take it apart, at lest that's fun... who knows, you might just find the problem. But in any case, if you find the parts that are bad then look at the part numbers and Google them. You'll find a rage of prices for these parts. As example, a couple of years ago I decided to fix my Craftsman 20gal vertical oiless compressor. It need a rod/piston kit. I found the cheapest place to buy was only 24 miles into town and was an Ingersol-Rand part. That pleased me.

 

[Josh_Br]

Thanks guys. I'll have to check into what you guys mentioned and see where that gets me. It'd be great to fix this thing.....new compressors aren't cheap!

 

[Josh_Br]

Ok - Last night I got to spend some time working on this. I think it was fruitful

I already had the motor and pump removed from the rest of the compressor. I wired up a cord with a plug, and plugged it in. It did absolutely nothing. No sound, no indication it was trying to run.

I unplugged it and took half the plastic housing off. I turned the pulley by hand, and it turned pretty freely. I plugged it in again, and then it ran.

I put it back together, plugged it in, then it wouldn't run at all - nothing again. I took it back apart, turned the pulley by hand, then plugged it in again, and it ran again.

This seems to be where it's at. Sometimes when I plug it in, it does nothing. But then if I unplug it, turn the pulley by hand, then plug it back in, it runs. I actually ended up cutting a hole in the back of the plastic housing so I can reassemble the whole thing and easily give the pulley a turn by hand if needed.

That being said, does anyone have any idea how to actually fix this, or what the problem is? I lubed up the moving parts while I had it taken apart. Nothing seemed bound up.

Thanks,
Josh

 

[LEVE]

When it is NOT starting, does the motor hum, or even attempt to start?

 

[Lightfoot]

i'd check the cord connections at the motor and at the plug end, and the power cord for a break. Movement of the cord connections may be causing the intermittent issues. Take the cord loose and hook up an ohm meter at each end of the three wires then wiggle the cord. won't cost anything for a starting point anyway. Or try a different cord if you have one. Then i'd check the motor brushes.

 

[Josh_Br]

When it's not starting, it doesn't hum or anything. It does absolutely nothing at all.

I was wondering about the motor brushes.

 

[Josh_Br]

This afternoon I hooked up the motor back up to the rest of the compressor and let it run for a few minutes. The motor speed fluctuated some, and it didn't seem like it was running at full speed. Despite these things, it was still running and putting air into the tank. Then it started to smell bad and there was some smoke. I shut it off and took the shroud off to see where the smoke was coming from. It was coming from the end of the motor, the end with the brushes and the fan.

 

[Outlawmws]

Get the brushes out, they may be worn out. or you could be having a wire melt down near the brushes.

 

[Josh_Br]

I was wondering if it would be best to replace the whole motor/pump. Not that I want to, but given the smoking and everything.

I searched online and most places the motor and pump are around $200. However, on this one site it's $137. Almost seems too good to be true, but the part numbers match up. I also did the live chat and they verified it's the right part number. Any thoughts on this? Here is the part: http://www.m-and-d.com/DV-Z-A04714.html

Thanks,
Josh

 

[rlitman]

Too good to be true? It sounds like your motor and pump may be fine, and you have an electrical issue.
If your motor has brushes (a picture would really help here), you may only need $5 in parts.

 

[Josh_Br]

I am a rookie here, but if you guys really think it might only be a brush issue, I'll gladly try that route. I'll see if I can track some down online. Thanks

 

[mayday0017]

How much is a whole new compressor like the one you have? $137 sounds like over 50% of what a new one would sell for, and next week it could be the pump that goes out.

 

[mayday0017]

Try taking the motor to a local electric motor repair place, many alternator repair places fix electric motors....

 

[Josh_Br]

I think a new compressor would be about $300.

 

[mayday0017]

This should be pretty much the exact same compressor you are talking about, only difference is what the label says about HP, but I almost guarantee even that is the same. Sears was known for misrepresenting the HP on their products.... For best comparison look at the CFM advertised on both, and most importantly the Amps listed. Only other real difference is the tank is a little bigger.

$200
http://www.craftsman.com/craftsman-...p-00916913000P?prdNo=1&blockNo=1&blockType=G1

 

[Josh_Br]

This afternoon I hooked up the motor back up to the rest of the compressor and let it run for a few minutes. The motor speed fluctuated some, and it didn't seem like it was running at full speed. Despite these things, it was still running and putting air into the tank. Then it started to smell bad and there was some smoke. I shut it off and took the shroud off to see where the smoke was coming from. It was coming from the end of the motor, the end with the brushes and the fan.

I should have also mentioned it was throwing off some sparks, and visibly sparking a lot as the armature rotated.

This should be pretty much the exact same compressor you are talking about, only difference is what the label says about HP, but I almost guarantee even that is the same. Sears was known for misrepresenting the HP on their products.... For best comparison look at the CFM advertised on both, and most importantly the Amps listed. Only other real difference is the tank is a little bigger.

$200
http://www.craftsman.com/craftsman-...p-00916913000P?prdNo=1&blockNo=1&blockType=G1

Thanks for the tip about the CFM. This explains why it was hard to find a 3 HP compressor for any decent price.