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.

It's a medium duty truck but it doesn't have air brakes. I have a torque multiplier but it is missing its original handle and I was using a piece of 3/4 steel rod as a handle. I only succeeded in bending the rod when I started putting pressure on the breaker bar. Perhaps with a better handle, the torque multiplier might work but I think I really need the hammering of an impact wrench as Brian noted.

I don't suppose the lugs on the left hand side are left hand thread? Quite common on medium duty trucks.

Ive been bit by that before. Wonder what they are torqued to now?

They are definitely left hand thread on the left side.
Don't know who torqued them or to what load but I figure me standing on an approximately 6' breaker bar had to be getting at least around 7-800 ft lbs and it wasn't phasing them at all.

Call a tire shop. I don't believe your small compressor will put out enough cfm's to push your 1". Remember, the second you hit the trigger, the pressure drops and your gun probably flows about 9 cfm's or better in a minute. I have a 60 gallon tank with an 8 HP gas engine powered compressor. When I use my 3/4" impact on a set of 19.5" Budd lug wheels I have to wait for it to refill after about three lugs.

A C.F.M. is a 3X3X3 cube of air at 150 p.s.i. How big is your tank again?

There are some torque multipliers available that are set up specifically for lug nuts, where the "reaction bar" hooks on to another one of the lugs or lug nuts on the wheel. I've never used one like that, but here's a cheapie from Harbor Freight that shows the general layout.

I'd never heard of them until I did a little research after picking up a 3200 ft-lb. torque multiplier (not a cheapie) at auction a while back. Compared to any of the comparatively puny tools I already owned, wow, what a monster!

As already noted, no "hammer action" with these, but very potent if one needs straight-up torque.

I agree that the hammer action of am impact wrench is what you need, however if you arent going to buy a shop-sized air compressor anytime soon- where is what my dad always did.

Have one guy stand/pull/exert maximum torque on the lug nut using whatever means you have necessary (lengthen your breaker bar), hold that under torque and....

Have the 2nd guy get as large a hammer as he can hold with one hand, and pound on the nut, wrench or the metal (wheel) directly adjacent to the lug nut - tap as hard and as rapid as he(or she...) can - this hammering sets up vibrations that, in the absence of a "real" impact wrench, might break your nut loose (when the tapping and torque are applied at the same time). The harder you tap, the more the vibrations might work for you.

worth a shot IMHO- it has worked for me before.

-John

Well, I ended up using the pancake compressor because it was putting out around 110-115psi whereas the larger tanked compressor only had around 100psi. The extra psi seemed to make a substantial difference in power. I could get about a 5-10 second burst out of the compressor until it weakened. I worked on one wheel. Most nuts took about 5 attempts to loosen. One took 10-12 attempts but all nuts on that wheel eventually loosed. I retightened them with my 40" breaker bar.
One set of rear duals had been off recently when I had a flat on the way home from NC about a month ago. Those immediately loosened with the 1" impact. Don't know if I could have loosened those by hand since I don't have long enough 3/4 extensions at the moment to reach inside the dual wheel.

Glad you got them free. Now do yourself a favor. Take them all off, dab a small bit of Permatex Anti-seize lubricant, part # 80078, onto each lug and re-tighten. Not the nuts but the lugs themselves. You will NEVER have the problem again.

Anti-seize on lug bolts????

http://www.tundrasolutions.com/forums/tires-and-wheels/44792-anti-seize-lug-nut-studs-why/

What are people's opinions on this?

I would NEVER.


You'll be cleaning the thread everytime you take the wheels off, and it'll collect dirt that'll throw off you torque readings and do damage to the threads.

most 1/2in impacts do in the 5-600 range. mine on the other hand will do 1000. using the impact emits a shock to the bolt that helps loosen. and yes some lugnuts do use that kinda torque.

While I don't believe you would get into any major problems with it, the theory that it offers reduced friction and therefore increased clamp force does hold sway.

The stud is designed to be clean and lubricated with oil. That's probably the best choice. The oil isn't going anywhere for the period until the wheel is removed again.

Anti-seize has nothing what-so-ever to do with reducing the torque between the flange of the lug/nut, the rim and the axle/hub which is what holds the wheel on. It's the metal compression factor not the thread to thread metal contact which stops your wheel/tire assembly from becoming a Frisbee. Lightly lubricated threads will actually give you a truer torque because the friction factor between the threads is reduced.

How would a small amount of never-seize collect dirt in a relatively sealed environment?

I'll stand on my 35 years of fleet maintenance experience. I'll conservately estimate 3000+ tire removals/replacements on ALL manner of rim/wheel/vehicle combinations.

Anti seize is needed and like the one guy said, it goes on the face of the nut, as well as threads. The initial force is needed to overcome friction on the wheel face, not the threads.

The only problem is torque specs are rated DRY. Someone needs to find the proper torque using anti seize. Maybe there is a standard conversion factor, but I have never heard of one.

'll chime in with my 18 years of mechanicing (is that a word) I use grease or oil because I hate neversieze. That stuff seems to get everywhere. After i have used that stuff it winds up on my elbows my face everywhere. If we lived in the rust belt you might need neversieze but here in Colorado grease is more than enough protection.

I would put the anti seize on the threads (studs?) and keep it off of the lug nut seating surface (the curved or slanted part where the nut actually contacts the wheel. Keep the threads from sticking but let the nut "stick" to the wheel as it already has.

-John

We use Never-seize down here in the land of perpetual sunshine 'cause the heat turns the grease into oil which then collects the sand. Works pretty good as a sun block also. How can a 1'16" blob of Never-seize expand to cover your entire sleeve and the armrest of your car? Just an amazing, unbelievable contrast to one of the laws of physics.


"Mechanicing?? Hmm, sounds like a spreadable topping or what happens when you have to do automotive work at 20 below. "Jim, don't let Billy go out there to change your fan belt. That mechanic'll ice up without no protection"

Further question:
While I was able to loosen the left side lugs with the 1" impact and my small pancake compressor, I was unsuccessful on the right side. So now I'm thinking of getting another compressor with more 'oomph' rather than paying a shop to do it.
How much difference would using either 150psi or 200psi make in the amount of torque output in the 1" impact? I'm looking at a couple of used compressors on Craigslist with those outputs. Both compressors have tanks int he 15 gallon range so there will be more air to power the wrench.

Most air tools are only rated for 90 or 110psi. TO go above that is risking the life/safety of the tool (an impact wrench is not something I'd want flying apart on me)

I have seen "stuck" nuts, that required a full 15 seconds of impacting at full power to come loose. Count out 15 secs, thats a long time to hold an impact on a nut.... I'd venture that few 120vac air compressors would be able to make that much air (you'd need a 220v model...)

I have a good (Milwaukee?) 120v electric impact - it has yet to let me down - they cost more than air impacts but less than new air compressors. Its an option.

-John

The only electric 1" impact I could find on a quick google, was a Makita with 738 ft lbs of torque for $732. That won't cut it. My 1" HF air impact has 1400 ft lbs of torque at 100psi but I'm only getting a couple of seconds of output with my current compressor.

It would not surprise me at all if the 738 ft-lb Makita loosens a nut that your "1400 ft-lb" H-F wrench can't budge.

Guys - my indy just removed my wheels and told me they were on way too tight. I had used a breaker bar. He said to torque them to 80 foot lbs each; then re-torque a week or so later. 81 300SD. I realize you are talking about a truck but it sounds like the lug bolts have been way tightened over spec.

Any man of reasonable strength will overtighten the M/B lugs with an 18" breaker bar. It's inevitable. After they twist a few rotors, they realize that a $20. torque wrench might be a good investment after all...........:rolleyes:

a volvo shop i used to frequent in albuq used it all the time, and it seems like a fine product.

I had a flat at work last year in the spare car (no jack, no lug wrench; what can i say?) and a friend stopped by with his work truck (mobile truck tire guy) and absolutely hammered the lugs back on w/ a 3/4" gun. i needed heat to ge them off. i wish he had used something!

those guys one the toyota forum (linked above) are cool - one of them actually did his own stress/strain test on a bolt (measured length, same torque, lubed and unlubed...)

The evidence seems to point that using antiseize/lubricant DOES indeed put more "holding force" on the bolt. But no one could cite an experience where they lubed their threads and it caused the bolt to fail.

I'd keep using anti-seize as I posted above.

And I find it interesting that on the toyota forum, their dealer name is right next to their user name.....why are they so proud of their dealers ? =)

-John

As a follow up, I ended up taking the truck to a truck tire shop. They first tried with their 1" impact. 30 seconds or so on each lug made no difference. They then got a sledge hammer and a second guy hit the impact socket with the sledge while the other operated the impact. No go. Finally, they went and got 'Big Bertha', must be their most powerful 1" impact (Central Pneumatic no less), waited until their compressor was at full capacity and let them have it. After about 30 seconds on the lugs, it finally loosed them. No way I would ever have broken them loose by myself.

T'ing two compressors together will work if BOTH compressors are rated to handle the same P.S.I. compressing capacity and their holding tanks are similiarly rated...that also includes the T'ing components and related materials...the weakest item in all of this plumbing BETTER BE the pop-off values...

And, T'ing everything together will only get you more reserve pressure to last longer, not more pressure overall...two tanks of 200#s of pressure don't add up to 400#s of pressure...it just adds up to just two tanks of 200#s of pressure...period. Your tool will work about twice the time before it quits or the compressors kick back in to re-pressurize...

I use the anti-seize on the bolts and nuts...then the t-bar lug wrench...when the the t-bar quits spinning, I'm done torqueing...I've never had a tire fly off the car, a nut come loose or a nut seize on me while taking a tire off...

Now, the only other thing I could add is this...

Some tire shops have a set of "torque-wrenches" that they use on their air-guns in their shops...each one is marked on the perimeter of the torque-wrench head with a series of black "slashes" that "stop moving" when the proper torque level is reached...(sort of like the "strobe-lines" on the phonograph platters of record players back in the 70s and early 80s).

The "strobe-marks" on the torque-wrenches are aligned with the shop's flourescent lighting so if the mechanic is USING the flourescent lighting, those torque-wrenches are useful in getting you in the ball-park for the proper torque...but if they are using a shoplight (an incadescent bulb) and torqueing your nuts with that...you don't know for sure what the actual torque value is...

Better invest in a manual torque wrench and double-check their work...otherwise, you'll be loosening more than your tire's NUTS...

These days I always carry a blowtorch in my car. Might need it for quick plumbing duty and heat has worked very well for me on stuck nuts.

I did try heating the lug bolt with a Mapp gas torch and using a 6' bar. Kept the heat on for 3 minutes. Did not break them free. They were REALLY tight.

Whoa, and Mapp gas is pretty dang hot.

FWIW, I felt pretty sure that you had used heat already, based on your remarks on other DIY topics.

I dunno, if a 6' bar and heat won't do it, I'm not sure an impact gun will either.

I figured out that the impact wrench the tire shop used was pumping out 1800 ft lbs of torque.:eek:

Well, that's theirs. Does the one you have come close to that? Plus, their compressor is huge.

No. I think my 1" maxes out at 1250 and no compressor I am ever going to own is capable of putting out the volume necessary to get the full power. It was a pretty good sized shop with 5 double bays so their compressor has to be a monster compared to mine and even they waited until the compressor had reached full pressure before attempting to break the lugs free.

1250 might do it, even with the short bursts you're going to get. Jeez, my main client now (4 rentals and her house) lost her husband, a contractor, a few years back. Only 57, my current age.

She's got a solid looking gas powered, two tank, wheelbarrow type Emglo in her garage she wants me to sell. Wish I could loan it to you.

I might take it on trade for some hours myself.