Air tool question
 

The lug nuts on my Mitsubishi FG are overtightened. I tried a 3/4"x40" breaker bar with a 3' cheater with no luck. I have a 1" impact wrench. It's designed for use with 1/2" air hose and 12cfm. I have a small compressor (5cfm?) with 3/8" hose. What kind of performance will I get out of the impact wrench if I hook it up to that small compressor? It is rated at 1400 ft lbs under normal operation.
Will it harm the impact?
I actually have 2 small compressors. Could I T the lines together to get enough ooomph?

The compressor will work fine. It will peter out after about 2 - 4 seconds and you will have to wait for it to recover.

The real question is whether the compressor has a tank. If so, the requirement of the impact wrench can be met without the capability of the compressor via the use of the air in the tank. Naturally, the tank pressure will drop, but, you'll only need full pressure for two seconds to break the nut loose.

The 3/8" hose will limit the airflow somewhat and the wrench won't develop the rated torque.........not much you can do about that.

I might heat the studs if the ends are exposed. They'll lengthen slightly and the clamping force from the nuts will drop dramatically.

Yes, compressor has a tank. The larger one is 10 gallons I think. Smaller one is a pancake.

Naturally, the larger tank is preferable.

The impact won't help if a 3 foot cheater bar didn't break it, you get way more torque than a 1/2 impact generates. It is possible you can beat on it with the impact and then try again with the big bar and see if that helped.

The power the impact generates is only due to air pressure, the air volume it puts out determines how long that pressure can be maintained.

Thread dope will help in the future, but I think torque specs are listed as dry. I am not sure how you measure torque with dope. Is you use dope put some on the face of the lug nuts, when nuts get stuck it is usually not because they are bound up on the threads, but because they are bound up on the face of the wheel.

You're not going to develop 1400 lb.-ft. with a 3 foot bar..........unless you rent a gorilla.

Furthermore, the impact wrench has an advantage over a gradually applied force that is common with a breaker bar...........even at the same torque level.

It's a 1" impact that generates 1400 ft lbs of torque if operating under ideal conditions. I don't think I could exert that much force with a total of 6' of leverage.

The torque spec on the lug nuts is around 380 lbs. I'm hoping that once I get them loosened, I can retorque them and they will be capable of being loosened with a 40" breaker bar since I don't want to haul around a compressor and 40 lbs of impact wrench just to change a tire and wheel.

:eek:

A forklift is an 8,000lb chunk of steel on 10" wheels, they need lots of torque to hold the weight.

The lug nut torque for the semis I work on is 450lb-ft.

I think he meant 1400 inch-pounds. The 1/2 impacts I have seen claim in the 300-400 ft-lb range (I know the math doesn't seem to work out) with some high dollar ones getting to 600. A 3/4 can get 1000. You would have to go bigger to get 1400 and you would have a hard time holding it and it takes a LOT of high pressure air to run it, maybe more than a home compressor can generate.

But the impact will help to break things if they are going to break, problem is you have to keep recharging the tank to keep the pressure high enough to get full power.

With a 3 ft cheater a 200lb guy can sit on it for 600 ft-lbs, and you can easily pull 300-400 with your arms (times 3), especially if you jerk it.

Every time I had one stuck, the 1/2 impact NEVER worked and I had to use a regular breaker bar each time and it worked.

A torque multiplier makes easy work of things, never used one myself, you have to secure it to something so I am not sure how you would attach it to the wheel. Some front engine nuts have a 350 ft-lb spec (lug nuts DO NOT!) and you need a multiplier, mainly due to space limitations.

Is this a truck? 380 is not a car wheel by any means. If it is a truck you will need the 1 inch impact and lots of air. Be sure to use the anti-seize (thread dope).

He said his impact is a one inch.

..........I don't think we'd be having the discussion if he was considering 117 lb.-ft. The wheel would already be off the vehicle.

your mitsu does'nt by chance have air brakes!!if so the air reservoir tank usually has a couple extra plugs you can remove for a line.i did this on my freightliner.its not an 80 gallon tank but enough to at least crack the lugs loose,and thats the main mission.