Guys can I buy a electric Impact Wrench to undo lug nuts on my 5th wheel 120flbs?
I took back one I bought from H.F it would not move the nut at all.

try a dewalt commercial duty one, i have a few of them and they take the nuts loose on my dually truck and my gooseneck trailer

x2 i have an electric dewalt one and it works well

Snap on Cordless 1/2" impacts work pretty well also!

Snap on Cordless 1/2" impacts work pretty well also!
x2

Thanks I will check them out any mod #.
Den.

Snap on Cordless 1/2" impacts work pretty well also!
I agree with that. But $$$. He also specified electric.

^^ I know, but He also said that the electric one he had wouldn't do the job- I just wanted to give him an alternative in case he wasn't aware how they performed (Before I used the ones at the shop I work at, you couldn't have given me one cuz I thought that there is no way that it would do that much). Technically the cordless are electric!!!!
I believe that they are running this-
Snap On Impact (http://buy1.snapon.com/catalog/item.asp?P65=yes&tool=power&item_ID=89708&group_ID=19913&store=snapon-store&dir=catalog)

I know that they are expensive, but I'm pretty sure that they were cheaper than what they show online- maybe track down a Snappy truck with cash and wheel an deal??

I have a 24V that goes to around 200 pounds. It workes for everting I needed it for.
It's a Goodyear Racing, around $ 80.00 if I recll correctly. Been 2 or 3 years ago.

My Harbor Freight junk works fine, if i cannot break them loose from the start then i use a breaker bar. I always hand torque lug nuts when i put them back on.

Keep in mind if they've been on the trailer for a while they might have froze up a bit. Loosen them with a breaker bar and then use the gun from then on.

I break mine loose with a bar and then use my Craftsman 19.2v cordless drill to spin them off. They speed back on with the drill, then get torqued with a torque wrench.