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What the hell is wrong with my air compressor???

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Forum topic by LukieB posted 10-24-2013 04:00 PM 3332 views 0 times favorited 26 replies Add to Favorites Watch
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LukieB

939 posts in 1015 days


10-24-2013 04:00 PM

Topic tags/keywords: air compressor air compressor repair

Turned on the compressor this morning, It’s in the garage with a line running out to my shop. Went out to the shop for quite a while, came back and the compressor was still running. Figuring I’m a moron and didn’t close the drain valve last time I drained it, I checked that, and it was closed tight.

The motor is running, it sounds fine. I took the plastic casing off, and the cylinder is pumping. I pulled the filter off the intake and it’s sucking air. I pulled off the metal line going from the pump to the tank, and there is strong air pressure coming directly outta the motor. But no matter how long it runs it won’t build pressure past like 15 PSI. I can’t feel any leaks coming out anywhere,(and yes, I’m sure the drain valve is closed) and I am just baffled as to where the air is going…

Anybody got any ideas what might be wrong here??

The compressor is an older Craftsman probably early nineties?

-- Lucas, "Someday woodworks will be my real job, until then, there's this http://www.melbrownfarmsupply.com"


26 replies so far

View Don W's profile (online now)

Don W

15217 posts in 1253 days


#1 posted 10-24-2013 04:02 PM

valve(s) are gone (broke). You should be able to buy a rebuild kit for it. Replace the valves and tour back in business.

-- Master hand plane hoarder. - http://timetestedtools.com

View TaybulSawz's profile

TaybulSawz

133 posts in 368 days


#2 posted 10-24-2013 04:17 PM

What kind is it? How big? Direct drive or Belt? Replacement Kits can be expensive sooooo… be Aware!!!

-- Still got all my Fingers!!!

View Todd Swartwood's profile

Todd Swartwood

57 posts in 411 days


#3 posted 10-24-2013 04:25 PM

How does the air get from the garage to your shop??? I would suspect that their is a leak somewhere between the two.

-- Todd Swartwood (Todd Swart-Woodworks)

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LukieB

939 posts in 1015 days


#4 posted 10-24-2013 04:34 PM

Thanks Don, but what valve(s) do you speak of? The only parts that mention valve on the parts list are the pressure relief valve and the drain valve for the bottom…

Here is the compressor and parts diagram…

The problem lies in the compressor itself, not in the lines between the garage and shop. The motor is pumping and compressing air….it’s just not getting to the tank on the compressor. Like I said, I pulled off the metal line that goes from the motor/pump to the tank on the compressor and there is solid pressure there. But when I hook that line directly back into the tank, I’m not getting pressure in the tank past 15 PSI

-- Lucas, "Someday woodworks will be my real job, until then, there's this http://www.melbrownfarmsupply.com"

View JesseTutt's profile

JesseTutt

811 posts in 796 days


#5 posted 10-24-2013 04:46 PM

A few thoughts:

An air compressor should have a safety valve to keep the tank from exploding if too much pressure is pumped into the tank. Check that.

I assume that you don’t hear any sounds of air escaping?

If you have a shut off valve between the tank and the line running to your shop shut it off and see if the problem persists.

Is there any possibility of a leak in the tank?

If it were to run till the tank got 15 psi and then cut off I would think that the pressure switch was the problem. From your description it does not sound like this is the case.

-- Jesse, Saint Louis, Missouri

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crank49

3456 posts in 1656 days


#6 posted 10-24-2013 04:56 PM

+1 on shutting off the line going to the shop, and any other connections that might be leading away from the tank.

On the link you provided for the parts manual, at the bottom of the page is a link titled, “How to Fix a Valve Plate”
Do that if you are absolutely sure the air is not leaking from the shop line.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Don W's profile (online now)

Don W

15217 posts in 1253 days


#7 posted 10-24-2013 05:02 PM

there has to be a valve that keeps the air in the tank. In theory a compressor work like a gas motor, just in reverse. So the piston pumps air, which typically opens a valve, then when the piston stops pumping the valve closes and the cycle starts over.

Unfortunately I can’t find where that valve is in the parts diagram, but if I had to guess its B-63, which is in the picture, but not in the list.

If you remove the airline from the head to the tank, and air flows, and you can’t stop it with your thumb, (It will flow if there’s no resistance) then its something else, but the problem above has been what I’ve seen every time.

-- Master hand plane hoarder. - http://timetestedtools.com

View Don W's profile (online now)

Don W

15217 posts in 1253 days


#8 posted 10-24-2013 05:07 PM

I didn’t watch the video all the way through, but its not for that compressor. Michael is correct, but I think the part that’s no longer available on tour compressor IS the valve plate. Maybe a call to sears will get you a comparable part.

-- Master hand plane hoarder. - http://timetestedtools.com

View tefinn's profile

tefinn

1215 posts in 1122 days


#9 posted 10-24-2013 05:14 PM

crank49 nailed it! It’s the valve plate and/or the o-ring on the piston. Do as Don W suggested and check the pressure on the head outlet. If you can stop the air with your thumb it’s in the head.

-- Tom Finnigan - Measures? We don't need no stinking measures! - Hmm, maybe thats why my project pieces don't fit.

View Underdog's profile

Underdog

546 posts in 721 days


#10 posted 10-24-2013 05:18 PM

I’ve replaced the seal (30A) a whole bunch of times. It kinda comes apart after a few years, and you have to periodically replace it. Otherwise it leaks like a sonofagun.

That might be it.

Because of that leak, mine blew up when I left it unattended for a week while I was on vacation. First I knew of it, I came back, plugged it in and tried to run it. Breaker was tripped. Flipped the breaker, turned it on, and what was left of the rod flopped around until I shut it off again. I wound up buying a cylinder, rod, and piston. Oh. and the seal.

But it’s been running for years since that time. I keep several seals in stock….

View LukieB's profile

LukieB

939 posts in 1015 days


#11 posted 10-24-2013 05:34 PM

Well, it was difficult but I could stop the pressure with my thumb, so I tore into it a little further. Rubber O-ring was intact but it looked like something blew up inside there, scratches and gouges and little bits of metal and even a hole right in one of these metal flaps….. Guess I found the problem.

Now I just got to figure out what the hell I’m gonna about it. Just my luck it’s the one damn part ereplacementparts.com doesn’t have.

Thanks for a the help guys, you guys are awesome.

-- Lucas, "Someday woodworks will be my real job, until then, there's this http://www.melbrownfarmsupply.com"

View Tedstor's profile

Tedstor

1369 posts in 1318 days


#12 posted 10-24-2013 05:58 PM

Maybe Underdog will hookyou up with one from his stash ;)

View Don W's profile (online now)

Don W

15217 posts in 1253 days


#13 posted 10-24-2013 06:05 PM

if you can find out who made that compressor you may be able to find one. That’s he most likely part to go, so I can’ believe they don’t have it. If you can find a compressor shop they may be able to help. Maybe even Granger.

-- Master hand plane hoarder. - http://timetestedtools.com

View tefinn's profile

tefinn

1215 posts in 1122 days


#14 posted 10-24-2013 06:17 PM

That compressor was made by Devilbiss for Sears. Don’t know the comparable Devilbiss model though.

-- Tom Finnigan - Measures? We don't need no stinking measures! - Hmm, maybe thats why my project pieces don't fit.

View Underdog's profile

Underdog

546 posts in 721 days


#15 posted 10-25-2013 03:34 PM

Mine was a bit dinged up after the piston and rod blew apart. But I unbolted the reeds and flattened them best I could, then put it all back together.

It’s worked fine for quite some time. Now that I say that, it will be sure to puke it’s cookies again.

As for the stash, unfortunately, I don’t have any other parts except those seals.

showing 1 through 15 of 26 replies

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