So I have an old Craftsman oil less compressor, and the pump is dying. I've already ordered what should be a rebuild kit, but given how old the thing is, I'm not so sure it will work.
This is a direct drive pump system, which I really don't like- it's incredibly loud. But it also means that I can't just replace the pump and move on- there's no belt etc....
Is it possible to take off the entire pump assembly and replace it? If it is, where would I find an appropriate replacement? In theory, its a 240V pump, 5hp, 11.5 SCFM@ 90psi.
Getting a like compressor is north of $1000, so rebuilding this should be cheaper- even a $500 pump/motor assembly would be cheaper. Just don't know where to look.
If you are going to go the cheep rout scope the tank and make sure it is not rusted putted to bad
In reply to dean1484 :
It's reasonably well maintained...
If I keep this set up, one other thing I will add is a real air filter- should help keep the pistons cleaner.
Harbor Freight is your friend.
Compressor Pumps
Motors
The other option is to scour marketplace and craigslist for a used industrial compressor. That would be my recommendation. I've got about $800 in my 80 gallon Quincy. It will outlast me and my kids.
In reply to Toyman01 + Sized and :
My 5hp motor is still good, so in theory, I could reuse it- but I'm not sure how big the engine pully needs to be for the compressor one. The 5hp pump would be pretty awesome.
Although, I should check the boiler plate on the motor- to see if it's compatable... But it's all wired up and all.
In reply to alfadriver :
That's a possibility. It will depend on the output shaft and housing on your motor. Frequently the shaft is not standard and the motor housing and pump housing are one piece. While it can be done, it may require some fabrication. BTDT
As to the pulley size, the pump should have an RPM range. Pulleys are determined by the motor RPM and the pump RPM. When I put the motor on my Quincy, I actually undersized the motor pully a little to slow the pump down. I don't need 19 CFM at 175 psi in the shop and turning the pump at 600 RPM instead of 900 RPM helped the noise level significantly.
Toyman01 + Sized and said:
Harbor Freight is your friend.
Compressor Pumps
Motors
The other option is to scour marketplace and craigslist for a used industrial compressor. That would be my recommendation. I've got about $800 in my 80 gallon Quincy. It will outlast me and my kids.
I agree. I replaced my compressor pump with a somewhat comparable one from Harbor Freight.
In reply to Toyman01 + Sized and :
When I take it apart to "rebuild" it, I'll get a look at the housing to motor set up. Take some measurements for the sake of it. For sure, some fabrication, as I have to turn the motor 90 deg AND put the pump next to it.
Now that I know I should be able to put the big pump on it, that should work great. After you mention it, the pumps all do have a speed rating- so I just need to know the speed rating of my motor.
If it happens, it will be in a build thread.
Replacing the guts of an oilless compressor will get you back to liking, if not loving, oilless compressors. They get quieter and air up pretty quickly. You will be pretty happy with the rebuild. Cant beat em for simplicity but they are loud and annoying.
I had a very comparable big Craftsman oilless that was a garbage day find 15 years ago, rebuilt the pump twice in that timeframe. I finally sold it when I dumpstered a big ol tan Ingersoll-Rand 2 stage conventional unit that just needed a new cord and some air fittings. Ran that for 3 years then rebuilt the compressor. It got a lot quieter after the rebuild and aired up quicker. The Ingersoll is a keeper. The low frequency thrumming is much preferred to the high pitched racket of the oilless.
In the short term (or long term if you're lucky) you can likely find a good compressor with a rusted tank and scavenge the motor/pump off of it. That's what I did. I had a cheap overseas oilless compressor and the head cracked. Instead of fixing junk, I found an old John Deere compressor for $20 with a rust hole in the tank. It was likely from the 70s given the logo, and I discovered they were made for JD by DeVilbiss.
Still going strong many years later. It's overkill for the small tank but perfect for wheeling around the farm instead of either running tons of hose or trying to drag the 60 gallon upright to the work.
So the easy button is holding- I managed to find a rebuild kit that fits my compressor. And I had to replace the safety cut off switch, as it failed, too. But other than that, it works again. And seems quieter with the new rings.
I don't see them lasting that long- the materials were not all that great. So I'll need to cross check those parts with the actual value you get from amazon costs.
The last one I worked on, all the rings and valves were plastic. The cylinder was stainless sheet metal. Most of the aluminum casting was for looks.
The motor on an oilless compressor will be difficult to adapt to a regular compressor. You'll have to fabricate a method of mounting the motor, as well as adapting it to fit a pulley- that may require some machining on the motor shaft.
Toyman01 + Sized and said:
The last one I worked on, all the rings and valves were plastic. The cylinder was stainless sheet metal. Most of the aluminum casting was for looks.
The cylinders looks really nice- even had some plating on them (can't really tell what it is). But the rings seem to be a combination of fiber and plastic- and that's where it seems cheap. Maybe a long look will help, but there are no other rebuild parts for me- which is just the rods. Heck, even the gaskets don't really fit- but I could reuse the one original that I had to. Funny about the O ring- it's sized totally for the cylinder- which was a perfect match for what I had- but the O ring was too big- go figure. I suppose I could get that intermediate head (the reed valvetrain, lol) that would match. But that will be a few years off until this fails.
I should go out and see if there's any residual pressure left- nice to not have leaks. Oh, and I got a drain valve that is easier to reach and operate- so I can drain the tank easier. no more putting that off like I did before.
stuart in mn said:
The motor on an oilless compressor will be difficult to adapt to a regular compressor. You'll have to fabricate a method of mounting the motor, as well as adapting it to fit a pulley- that may require some machining on the motor shaft.
As I rebuilt it, you are 100% right. Which kind of sucks, since I have a nice 5hp electric motor. Maybe I can figure something out if I had to- for the 5hp HF air pump, I'd need a dual band pulley anyway.
Its not like a new motor will put you in the poorhouse, they are under $200 all day long, under $100 if you know where to look.
Remember its not that a compressor needs 5HP, oilless units run at high RPM so thats where the extra HP comes from. Its comparable power to a 2HP 1800 RPM motor. The engineers math it out to 4.xx horsepower, then marketing applies their marketing math to round up to 5HP and boom.
In reply to 93gsxturbo :
This is true. My 80 gallon Quincy is running a 3hp motor an makes more air than my pressure pot sandblast rig uses.
