Craftsman impact gun problem
 

Last year, a friend gave me a medium duty 1/2 drive impact gun from sears as a wedding gift. I had my compressor loaned out to another friend for almost a year, so I never used the impact gun.

Last night, I was swapping on my winter tires and decided it was time to crack the box and use my "new" tool. I oiled it and ran the compressor up to 90PSI.

The thing wouldn't even loosen my lugnuts. In fact, I could hold the socket and prevent it from turning, even at the highest setting. It says it's good for 350ft/lbs.

I checked the manual... I had the right air pressure and the right size air hose. Is there something else that I can check? I don't have a receipt so Sears won't help me.

How big is your compressor's tank?

If it's faulty, you can always take it back for a new one

20 gal. Not ideal, and I'm going to get an upright 60 in the spring.

Still, I should be able to power an impact gun, even if the compressor cycles like mad.

I don't think you need a receipt to take it back to Sears.

Call them.

I called them and the guy was a peen about the fact that it's 1.5 yrs old and I don't have a receipt. Maybe I need to just bring it in and speak loudly.

I don't know. I used to run a 26 gal and I had trouble running an impact. I think it may also have to do with the HP of the motor as well.

I'd also check to see if you have moisture accumulating in the tank/lines

There should be no trouble with returning it at all. Call sears corporate if you have trouble. I once returned a 20 year old torque wrench with no problems.

Well, I could run the impact (albeit ineffectively) for a good 15 seconds before the compressor would kick in. If it was going to do something, you'd think 15 seconds would be enough time to spin a lugnut.

what HP is your compressor's motor rated at?

It's not a compressor problem.
The motor may be gummed up.
See if you find some of that air tool oil that smells like wintergreen. Good for loosening the gunk. Or shoot some break-free down the pipe and run it, followed by oil. Unscrew the adjuster all the way out and make sure that passage is clear. Sometimes a peice of machining crud gets left in when they're new...

That I'd have to check. Even then, once it's holding 90psi it should be able to spin the thing, no?

Perfect, thanks! That's exactly what I'll check tonight.

There are some little 'hammers' in the motor that have to freely beat theire respective 'anvils'. Run it with a light load for a while and see if it doesn't break loose.
Nothing to lose.

Dan is right. Hell I've run my impact wrench off of the compressor I use for my nail gun. It only has a 5 gallon tank. Work just fine in short spurts.

Look under the trigger is there a round adjustment dial? Many guns have an adjustment for power is it possible yours is set at the lowest setting?

Our shop compressor was set to kick off at 125lbs, no doubt some loss by the time it got to the toolthroulg the lines and hose. Tank size shouldn't be the limiting factor, you'll just have to let it catch its breath more often.
Jim

You have to check the requirements for the impact wrench.
In my case I bought a Husky impact wrench that requires 5.1 cfm (cubic feet minute) @ 90 psi to allow the 350-375 ft/lb torque.
My compressor is a 4.2 cfm @ 90 so basically it doesn't have the guts to use that impact wrench, I have to break the lug nuts loose then the wrench will do the rest but no way it will ever have the power to undo lug nuts.

Actually I'll sell my compressor and buy a new one with enough volume@90psi but I found they're all belt driven. The small ones like mine have the built in pump and motor and at least in Home depot none of those small ones will give the volume @ 90psi.

I highly doubt the wrench is gummed because they're oiled in the factory and comes with caps on all ends.

-Jasper

Jasper
I believe the 5.1 cfm for your wrench is referring to constant/steady usage. Assuming a large enough line is present I would expect a compressor with even a one gallon tank to break loose a lug nut.
Jim

Agree with Dave. Put some oil in the air input port and run it on and off for 5 minutes or so. Something is gummed up inside and not working right. 20 gallons is more than enough, and 90 psi is fine for this.