Impact not strong enough

[bw4sale]

My impact gun works on most things but won't break the ubolts on a rearend loose. It just doesn't have enough torque. I've had this problem on two trucks. Is it the gun or something else? It's a Kobalt. I've got a 60 gallon CH compressor. Thanks.

[Lee H]

That gun is not the greatest but the unbolts are tough. 3/4 inch Breaker bar and probably a chunk of pipe if they have been on for a while.
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[DennisP]

You should try a Dewalt electric impact. It really has BALLS!! Price around $100.00

[gmtec93c1500]

what size hose you running? what the pressure? 3/8" hose is a minimum, a good test of flow at the hose end itself and get a T fitting and a psi gauge and install it at the quick connect. check the pressure with your impact gun running i think most air tools run around 90 psi OPERATING pressure. so even with the compressor set to 150 shutoff, if you had small lines and tight bends ... there might only be 70-80 psi at the fitting going into your impact.

[Bus Ted Knuckle]

Yeah, lots of variables will contribute to actual torque values produced at the business end of an air impact. Some variables are: actual output of your compressor (CFM produced, vs. rated CFM), length of hose/pipe run from compressor to gun; size of hose/pipe from compressor to gun; actual torque output of gun vs. rated output; adjustment of the impact; condition of the impact; and even if the impact has been oiled. That "output vs. rated" stuff is very important nowadays, the manufacturers have all sorts of creative ways to test their tools to get high rated numbers.

You might just have to break them loose with a breaker bar, helped by a cheater pipe, then finish with the impact.

[pat 70/71]

Try a product called pb blaster, I had the same issue on the underside of three truck I've restored. stuff really works! cheers, Pat

[Maxxd07]

Seems like no matter what impact you have leaf spring u-bolts always need to be broke loosened with a wratchet or breaker bar and tightened with a breaker bar. They are just soft enough to absorb the impacts from the impact and will never get tight enough nor loosen even though the nuts will not be seized or torqued to more than spec.

[Tx Firefighter]

Originally Posted by Maxxd07

Seems like no matter what impact you have leaf spring u-bolts always need to be broke loosened with a wratchet or breaker bar and tightened with a breaker bar. They are just soft enough to absorb the impacts from the impact and will never get tight enough nor loosen even though the nuts will not be seized or torqued to more than spec.

+1. The springiness of the u bolts absorbs the force of the impact.

[NONHOG]

Not always a good idea as it could ruin a seal in no time but what about heat?
My propane torch has helped me many times free up a tight fastner.

[68Gold/white]

Heat on u bolt nuts won't affect an axle seal..
The biggest enemy you are fighting is corrosion. A Kobalt impact is a pretty good one, but not much compared to Snap On and others...the newest 1/2"Snap On will take the lug nuts off a semi, THAT'S an impact, don't ask the $$$...

Truck spring shops can custom make new u bolts, usually less than $10.00 each, and many folks sell them, also. I'd reccomend replacing them anyway, if yours are original.

[odog]

We have this problem on our rocksaws occasionally. We use 1" bolts to secure the cutting pads to the chain and a 1" impact hooked to a 185 cfm compressor(so I know we r getting plenty of air.) Sometimes the bolts will not break free so rather than cutting them, I rap the head of the bolt with a 3 lb hammer, hard, but straight on. This seems to "shock" the steel enough that the impact immediatly lossens the bolt. I know this is hard to do on a u-bolt, but may work in other areas.