Weak Air Wrench Or Bad Compressor

[Canadian Charlie]

Here is my story and I hope someone can help me out. I have an impact wrench and it doesn't seem to loosen the lug nuts off my Chevy pick up that are torqued at 120 ft/lbs. They just won't budge and I have to get a breaker bar to loosen the nuts before the impact gun can do its job. I hooked up an tire inflator gauge and noticed that the line pressure is at 60 PSI.

What gives? Even wheels that are torqued at lower specs are hard, the gun has 4 positions and I always keep it on high (number 4)

By the way this impact gun is a no name brand if that helps

 

[OctaneMotorsports]

The gun being a no-name brand is probably your problem. Try cleaning out the little filter screen at the air inlet (once you remove the coupler). If that gets clogged up the gun won't be as powerful.

 

[Canadian Charlie]

Its a brand new gun, I might have used it a few times at the most

 

[goodfellow]

Barring a clogged inlet, a little more info on the size of the gun and the type of compressor you have (HP, tank size, direct/belt driven pump, etc) would help. If it's a standard 1/2" impact, then the optimum psi should be around 90. If 60 psi is all the you can muster at the gun, then you may have a pressure drop and you should get a shorter air hose, or you could also have a bad pressure regulator at the compressor end.

 

[OctaneMotorsports]

Is it one of these guns? (With or without rubber boots)

I've seen these re-branded and re-labeled under a multitude of names, basically a general cheap chinese impact gun...probably the same or similar to the one you have. That said, I have one of these, and I've undone lugs on a Dodge Ram 3500 dually (not sure of the exact torque specs, but I would imagine pretty tight). Took a few seconds, but they came off.

 

[Canadian Charlie]

My compressor is a 100 litre, belt driven, 240 volts with 2HP as it says on the side. The gun is a 1/2" model

 

[Canadian Charlie]

Yes my gun looks alot like that but without the name on it

 

[OctaneMotorsports]

Yep, those guns come with all kinds of brands on them. They are rated to 250 ft/lbs, so you shouldn't be having a problem. Try and get the imput up to at least 90 psi.

 

[OctaneMotorsports]

P.S. what is your air hose I/D? 1/4"? 3/8"? 1/2"?

 

[Canadian Charlie]

I just went down to the garage and turned up the pressure on the compresor to about 95-100PSI and i still can't get the damned bolts off the wheel. I think my air line is 1/2" ID

 

[Canadian Charlie]

P.S. what is your air hose I/D? 1/4"? 3/8"? 1/2"?

Does air line I/D effect it?

 

[Deafautotech]

yes if have smaller air hose then it is less air inside, if have big air hose like 3/8 hose or even 1/2 hose then it have more air psi inside. more psi go throught the hose equal more air go to air tools. i did have 1/4 hose and it is **** while it come in package. so i did bought 3/8 hose x 25 feets. it is pretty good and work on all air tools.

 

[KeukaDan]

yes if have smaller air hose then it is less air inside, if have big air hose like 3/8 hose or even 1/2 hose then it have more air psi inside. more psi go throught the hose equal more air go to air tools. i did have 1/4 hose and it is **** while it come in package. so i did bought 3/8 hose x 25 feets. it is pretty good and work on all air tools.

Larger ID means higher flow not higher PSI, PSI is not affected by hose orifice size.

 

[Deafautotech]

Larger ID means higher flow not higher PSI, PSI is not affected by hose orifice size.

Damn it. i forget that it is meaning to be high flow not psi. sorry if i make confuse for you. sorry again...

 

[Ironcrow]

Yes, but small hose will drop more pressure when the air is flowing. I'd hook a pressure gauge up at the end of the hose, right at the gun. See what it reads when the impact gun is running. Turn the pressure up at the tank until the pressure gauge reads 90 psi with the gun running.

 

[SteveU]

I have one of those cheap impacts that would struggle to take lug nuts torqued to 100 lbs off & would have to hammer on them for a couple of seconds before they came off. Replaced the exhaust pipe that bolts up to the exhaust manifold on a toyota corolla which is held up with 2 bolts, had to hammer on that probably 15-20 sec using 90 psi & 3/8" hose. Put HVLP fittings on it which helped some but the real solution was to get a 1/2" Nitrocat. With HVLP fittings it will loosen bolts that a 200 lb man bouncing on the end of a 4' cheater bar didn't get.

 

[eschoendorff]

You may have already thought of this....

have you lubed the gun? I don't mean the air motor, I mean the impact mechanism. I had a gun that seemed weak, so I drained the oil oil out of the impact mechanism housing (it was gray and cruddy looking) and put in some marvel mystery oil. Runs like a new gun. Just food for thought...

 

[MarkH]

I got one of these from a Cummings sale. I have never been able to make it remove bolts that a good 3/8 air ratchet removes with ease. I think they make them without any testing so you can get working ones most of the time and the rest of the time a paper weight.

 

[Deafautotech]

i would do open my few impact wrenches to see if it need drain and refill by air tool lube from LUCAS product. i think my snap on IM5100 need drain it and clean inside then lube inside and put it on again. test it when finish with it.