Craftsman 33 gallon compressor leak

[Trock03]

Gents,

I'm hoping someone with more knowledge than me can chime in and help me trouble shoot a leak I've got on my compressor. This is one of the loud oil free compressors. Roughly 8 years old. When it's pressing up there is air coming out of the area where the aluminum tube goes into the black plastic housing in the attached pic. Takes forever to fill up but when it finally cuts out there's no leak. Only leaks when the pump is running. Seems like the end of the aluminum tube is loose in the black piece as you can move it around a bit. Any ideas on what the fix might be (other than buy a real compressor)?

TC

 

[Yamaguy]

I have a similar compressor and had almost the same thing happen 4 years ago. My leak was at the tube from the compressor that connected to the valve body with a 3/8 compression fitting that was not tightened all the way. Mine had the same symptoms as yours I’ll take a pic when I go out there later.

 

[Lassen Forge]

I would say that it's plumb wore out. 8 years on an oilless is pretty good service for one of them.

Likely the check valve is loose (see above) or shot, you could try pulling it apart and seeing what isn't working or what's worn out... might be a drawn out $500 solution for a $100 compressor, tho.

 

[Trock03]

Yamaguy - that sounds about right. I'm going to run out and blew it down in a little while and will take the check valve and bleeder tube to see what the problem is.

Lassen - it may be getting close to wore out but it doesn't get just a ton of use so she should still have some life left in her...... unfortunately. I'm starting to look for an excuse to buy an oil lubed compressor. I might have my excuse now!

TC

 

[cheechi]

I have one of these Craftsman 33 gal about the same age as yours. Nowhere near daily use though on mine. Shortly after I got it I noticed it wont hold pressure over a few days, its about 1 psi per 2 days at first but after a week or so its down to 50 from full. I never could find the leak on mine but next time I fill it Im going to check that fitting. I'm thanking you in advance for that photo Yamaguy.

 

[Trock03]

Looks like that black plastic piece is the pressure relief valve. Next question, is there anyway to tighten the connection where the bleeder tube goes into the valve (JB weld?)? Or am I looking at buying a new relief valve and making a new bleeder tube?

TC

 

[kythri]

What's the model number of your compressor?

 

[Trock03]

Model 92116472

Did some more research last night and I found out that air leaking at the unloader valve is usually a sign of a bad check valve.
Unfortunately I had already yanked the bleeder tube out of the onset valve and the push lock connector for apart in the process. Needed to be changed anyway because the o-rings we're pretty brittle.
Ordered a check valve and unloader valve. Will get it back together and wait for some Black Friday deals.

TC

 

[Citation]

Unless this is a daily use compressor it's very unlikely the pump is worn out. Even then you can buy a rebuild kit so, noise aside there isn't a great excuse for replacing the pump just because it's oil free.

The aluminum tube leads to the pressure relief valve. If the connection between the valve and tube is leaking you might be able to reseat the valve. I think it's a push in to lock/unlock type pressure fitting. If it's the valve that's leaking you can replace the valve itself.

If the air is leaking after the compressor is done then you have a bad check valve. Note the pressure relief valve dumps for just a few seconds after things turn off.

 

[dogdog]

Model 92116472

Did some more research last night and I found out that air leaking at the unloader valve is usually a sign of a bad check valve.
Unfortunately I had already yanked the bleeder tube out of the onset valve and the push lock connector for apart in the process. Needed to be changed anyway because the o-rings we're pretty brittle.
Ordered a check valve and unloader valve. Will get it back together and wait for some Black Friday deals.

TC

I have a 33 gallon craftsman oil-less for mine, Not sure if it is the same model, but mine is older, 12 or 15+ years...

anyways... you can replace that aluminum tube with a copper one, I think it is just a 3/8 tube... I got all the ferule and compression fitting from home depot... the smaller tubes for the pressure switch is 1/4 ones...

when I had a leak, it was no leak at any fitting, the compressor would charge up but takes a while... then if I leave it off and nothing connected, verified no leaking at any of the fittings, the tank would be empty in a day or less... (I had a thread asking for help some years back here)

anyways it turned out to be the check valve. I just took it out, dump it in the HF ultra sonic cleaner with some baking powder... .and cycle it a few times, leave it soak for a day and cycle it again few times... it's been good since. air holds for months without leaking out.


Replacement is about $16-ish... I think I found it on ebay...

But if you problem is not the check valve, and you compressor is charging up slow or not to the PSI at all... then your problem might be the reed valve inside the oil-less compressor, that replacement cost $50+ shipping... like my 15 gallon one... I just use it as a extra capacity tank.