Craftsman Compressor Woes

[goingtoarizona]

25 Years ago I bought my 5HP 60 gallon Craftsman air compressor. Since day one it's spewed oil out the oil fill/breather. After buying our current home I'm FINALLY installing my compressor and turned it over by hand to ensure everything is ok. It whistles out the oil fill cap (there's a 1/8 hole to act as a breather in the side of it). I'm assuming that the cylinder or rings were never broken in or there is some other problem. Has anyone else had this problem ? It's 919-175251 model.

 

[Cyberbear]

Have you first tried contacting the Sears service dept. and asked them about your problem, more for service information and not about warranty info.

 

[Fixnair]

Break-in is not necessary with today's machining practices. In years past it was impossible to manufacture a truly round cylinder or a round piston ring. ( well, within reasonable cost.)

Is this a single stage compressor or two stage? In either case it sounds like the cylinder, ring or piston assemblies are not right. Too much clearance or cylinder scoring.

If it is a two stage compressor there is a possibility the high pressure (smaller cylinder) is not functioning properly. Look for bad valves. There should be a finned tube commenting the 1st stage cylinder to the 2nd stage cylinder. Look for a place to attach a pressure gauge on this finned tube and run your compressor up to about 100 PSIG. The pressure in thus tube should be around 35 PSIG. if it is too high excessive pressure will escape past the low pressure piston and pressurize the crankcase.

Unfortunately, the only remedy for this is a new compressor pump. It would be too expensive to try & repair.

 

[goingtoarizona]

I called Sears, they only have rings kits for the small piston, which according to you makes sense. I suspect that one (and after your explanation, the small) piston has excessive blowby, just like a worn out car engine. If the reed valves were bad I'd expect it to blow out the intake or air filter. Time for a tear down to see what's really happening.

 

[crab]

Keep us posted on this one, I have a 60 gal. craftsman that's never really given me any problems. It is loud though. There is a video on you tube about rebuilding the compressor on one, looks pretty simple. I think the parts were around 50 bucks.

 

[goingtoarizona]

Sears wants $99.00 for the rings, as far as I can tell they don't supply gaskets. From your picture, it looks like yours is an oil less model, those are typically noisier.

 

[redmondjp]

Sears wants $99.00 for the rings, as far as I can tell they don't supply gaskets. From your picture, it looks like yours is an oil less model, those are typically noisier.

Well, since the OP stated that it's spewing oil out the crankcase, I don't think that it's an oilless

You can tear it down and inspect, but as others have stated, it's probably more cost-effective to throw a HF pump on there. But who knows? Maybe some idiot put all the ring gaps lined up so it's getting excessive blowby there, you never know - if you have an extra hour to spend, check into it.

If you do put on another pump, you will have to spin it at a 3HP rating. Your compressor is actually only about 3.2-3.3HP, not 5HP as stated on the label (big class-action lawsuit on this, google it and start reading), so if you do put a HF pump on it that says it is for 5HP, you're going to have to adjust the speed down a bit so you don't fry your existing motor. Plenty to read on this topic on this site if you do some searching.

 

[barks]

Twenty-five (25) years into the mission and now the "problem" gets addressed. Ignore it and live a fruitful life.

 

[Charlie51]

Twenty-five (25) years into the mission and now the "problem" gets addressed. Ignore it and live a fruitful life.

Yep...when life gets in the way, time has a way of flying by.

 

[crguy]

It'll be a waste of time to put a crappy HF pump on there. Go with one of the big name brands and get something that will last.

 

[Modern Garage]

I see this is a zombie thread from the middle of last year, bit I'm wondering if you're not over thinking this. Maybe the whistle from the oil fill is normal crankcase pressure from the descending piston(s).
Perhaps the whole problem is simply poor design and you just need a longer or better filtered vent.
Joe

 

[Streetbu]

Before you condemn the rings, I would pull the heads and check the reed valves and head gaskets. That is a much more common issue.