[malakilaki]

I just bought a Coleman Powermate Air Compressor with the idea of using it to remove and install tires; to dust off the air filter, engine area, and cabin area; to air out water from crevices after car wash; to inflate tires, etc... I opted for this model because of it's portability (only 20 lbs.)

I tried to remove the wheel nuts yesterday, but the impact wrench could not untighten and tighten the nuts with enough torque. I was hoping that I didn't have to use the tire wrench just like the tire shops.

The air compressor has a maximum pressure of 70-100 psi. The impact wrench has a max torque of 250 lbs at 90 psi. I regulated the pressure at 90 psi when I used it. There was no air leakage. The Helms manual indicate that wheel nuts on the Ody are tightened at 80 psi and I thought the impact wrench should be able to do it, but I still used the tire wrench and turned the nuts almost a full turn to make it tight. I'll be buying a torque wrench to see how tight is 80 psi so for now I used the common sense tight gauge.

For my setup, is that usual that I still have to use the tire wrench? Or, is there something wrong with my setup?

Thanks.

 

[nwf_snake]

Your problem is not pressure, its volume. A compressor that weighs only 20 lbs probably cannot provide the proper CFM at 90 psi to run the air tool. You probably need at least 5 CFM at the tool, counting the drop through your air hose. You would need something like 6 cfm at the compressor (its rating) and then a very short air hose run. The more CFM your compressor can supply, and the larger air hose diameter you use, the greater CFM at the tool.

 

[DTKWOK]

Can anyone please tell me what the torque spec is for the wheel lugs (ft-lbs)? The owner's manual said it is 80 ft-lbs for the spare. TIA.

 

[celler]

nwf_snake is right, you'll never generate enough volume with that compresser. Occassionally, my 20 gal. 3.5 hp Craftsman would cycle more than I liked with a 250lb torque wrench. You have two options: (1) get a bigger compressor (I would recommend at least a 20 gal. tank), or (2) get one of those electric impact wrenches.

Personally, I think air tools are the greatest thing since sliced bread. You'll start out with an impact wrench, next will be the air rachet, then comes the die grinder.

When selecting a compressor, be aware that the oil-less motors (most of the wheeled portable versions) will wake the dead. They are LOUD! No midnight auto repair with those puppies.

 

[Canodyssey]

The proper torque for the wheel lug nuts is 80 ft-lb. I agree with snake that the small coleman compressor cannot provide enough CFM for the impact wrench. It is good practice not to install the wheel nuts with anything but a good torque wrench.

 

[malakilaki]

nwf_snake - Thanks for the education in compressor 101. What does CFM stand for? Instead of indicating just the PSI rating, why don't they indicate the CFM output on the air compressor (at least the one I bought didn't say so on the box or in the manual) and the CFM needed on a tool for proper usage? An average consumer like me wouldn't know these technicalities. I had inquired with 2 tool store clerks about my setup and they told me that my setup should be fine. Well, I'll be returning that compressor. Thanks again.
.
DTKWOK - Wouldn't the torque be the same whether it's the spare tire or not?

 

[malakilaki]

celler and Canodyssey - Thanks, too. I wasn't aware of your posts when I was creating my reply to snake. I'll be returning the air compressor and I'll be getting the torque wrench.

How much would a compressor of 6 CFM cost? We're not talking about a compressor the size of a water heater, are we?

I figured since I'll be tinkering with my new accord and ody that an air compressor would be a great toy.

 

[overmyheadcam]

CFM is cubic feet per minute. Most compressors do have a CFM rating.

The Campbell-Hausfeld compressors at Wal-Mart and Home Depot have a table on the box showing what tools need what pressure and volume.

 

[celler]

You can probabaly get away with something like this:

http://www.northerntool.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=42690&prmenbr=6970

Vertical versions are available as well. Expect to pay $250 to $350 for something in this range. When you are really smitten by the bug, you'll find a way to put one of these jobs in your garage:

http://www.aircompressorworks.com/kaeser.htm

These are extremely quiet and generate enough CFM to paint a car if you want. But they are expensive.

Here's a good link on basic air compressor specs:

http://www.ultimategarage.com/compress.html

As to torque wrenches, Sears makes a decent one, Snap-On makes good ones, Facom makes the best IMHO. You can check them out at this link:

http://www.ultimategarage.com/toolset.html

Be careful with your new torque wrench. If you drop it, it will likely require recalibration. Also be sure and run it down to a low torque setting (~40 ft./lbs.) for storage.

 

[DTKWOK]

<font face="Verdana, Arial" size="2">Originally posted by malakilaki:
nwf_snake - Thanks for the education in compressor 101. What does CFM stand for? Instead of indicating just the PSI rating, why don't they indicate the CFM output on the air compressor (at least the one I bought didn't say so on the box or in the manual) and the CFM needed on a tool for proper usage? An average consumer like me wouldn't know these technicalities. I had inquired with 2 tool store clerks about my setup and they told me that my setup should be fine. Well, I'll be returning that compressor. Thanks again.
.
DTKWOK - Wouldn't the torque be the same whether it's the spare tire or not?</font>

An educated guess says they should be the same, just wanted to make sure, since the rim material is different between the two. Plus the fact that the 80 ft-lb spec was mentioned only in the spare tire section, made me a little hesitant. Thanks to all for clarifying this.



[This message has been edited by DTKWOK (edited 01-28-2002).]

 

[FW_in_OKC]

A ½” drive ft-lb torque wrench and a ½” break-over with the proper sized impact socket are my tire tools. I started carrying these tools about 10 years ago after a difficult tire change in the Arizona desert.
You see I had the tires balanced for a trip to California and the guy at the tire shop really honked those wheel nuts tight with an impact wrench. I’m guessing they were at 250-300 ft-lb or more. I hardly had a chance of loosening them with the dinky wrench provided with the car. A passerby had a large cross type wrench, which we broke trying to get the nuts off.
A large tow truck stopped (the kind used for semi trucks) and he had a compressor on board and a ¾” drive impact that barely got those nuts off. We installed the spare and the tow truck guys loosened and re-torque the wheel nuts on all my wheels to 90 ft-lb. I bought a torque wrench in California along with the right sized socket and have carried it for years. I got it calibrated in 2000 and it was right on the money.
When I picked up my new Ody last month, the first thing I did when I got home was to install wheel locks and loosen and re-torque ALL the wheel nuts. All were loose. I’d say about 50 ft-lb or so.
The moral of this story is DO NOT TRUST your impact wrench to set the wheel nut torque correctly. You may be sorry later at the side of a busy Interstate.

Fred

[This message has been edited by FW_in_OKC (edited 01-28-2002).]

 

[MerpsMom]

If ever in my life I've seen a guy thing....

 

[malakilaki]

I'm no Tool Man Tim. I'm just one of those wannabe DIYers who happen to be fascinated by the sound of an air tool reving at a high rpm. It is definitely a guy thing.

One could get carried away with air tools, but all I wanted was to remove the wheel lugs without breaking my back using the wheel wrench. Air compressors that are quiet and can be used to paint cars are beyond my dreams and means. Maybe someone in Odyclub has the dough to buy one and paint those SS odys with YY (Yolk Yellow).

Now that I know what CFM stands for and what a torque wrench is, can someone tell me what a 1/2" break-over wrench is?

Thanks for the tip on the use and storage of a torque wrench.

 

[celler]

Didn't mean to go overboard, needless to say, I spend a lot of time in the garage.

For your purposes (wheel removal), a 20 gal compressor will do the job fine.

Some of the references here to torque wrenches are confusing. A torque wrench is used to tighten lugs to the proper specification, not break them loose. It is designed as a measuring tool. Using a torque wrench to break loose overtightened lugs will almost certainly effect its calibration and make it useless as a measuring tool.

What FW refers to as a "break-over" is more commonly referred to as a "breaker bar". This is nothing more than a 1/2 inch drive socket wrench (without the racheting head) with an extended handle for greater leverage. Snap-On makes a combined speed/breaker bar that allows you to break the lug nut holding the bar parallel to the wheel, then (without removing the socket from the lug nut) rotate the bar perpendicular to the wheel and spin the nut off using the S shaped crook in the bar. This is trick if there is no compressed air around.

FW is dead on target about the wheel gorilla's overuse of the air impact wrench. I rotated the tires on my wife's wagon last weekend and it took some effort with my 650 ft./lb. gun to get them off. The dealer had checked the brakes during an inspection and I had not followed up to check the torque. If we had a flat on the road, we would have never got those lugs loose.

 

[nwf_snake]

As a founding member of the
"Whoever dies with the most toys, Wins!" Club, I'll add another two cents.

I have a small Sears one-horse compressor, with a seperate air tank, to fill tires and blow air. It only delivers about 3CFM at 90 psi, but will keep auto and bike tires inflated without a problem. I'll fill the air tank when we go to the beach/pool, because I don't have as much "hot air" as I used to! I then have an electric impact wrench to take the lugs OFF the wheel. I always use a torque wrench for final tightening, but often use the electric impact to get them a little snug first. Never had a problem with warped rotors in the 15 years I have used this method. Good luck!

 

[Maugham]

<font face="Verdana, Arial" size="2">Originally posted by MerpsMom:
If ever in my life I've seen a guy thing....

</font>

Ernest Hemmingway would have kept a portable air compressor in the back of his Ody

 

[celler]

<font face="Verdana, Arial" size="2">Originally posted by nwf_snake:
I have a small Sears one-horse compressor, with a seperate air tank, to fill tires and blow air. (snip) I then have an electric impact wrench to take the lugs OFF the wheel.(more snipping)</font>

Excellent setup! I do not have an electric impact wrench, but I have heard many good reports. Only downside is maximum torque on most of them is under 100 ft./lbs., so if the wheel gorillas have struck, you'll need a backup breaker bar.

Instead of carrying an air tank, which can be bulky, I carry a small 12 volt Black and Decker compressor in every car. Its about the size of two coffee mugs. This is much slower than your tank, but very space efficient. Needless to say, this will not power air tools.

Unless you are in the habit of checking the air pressure in your spare, carring a small air compressor or a tank is a great idea.

I take it one step further and carry a tire plug, rasp, and insertion needle. Combinded with the compressor (and a little luck in finding the puncture) you can get back on the road without having to remove the tire. I know this is beyond what most folks are prepared to do, but its actually easier (and safer) than jacking up the vehicle.

------------------
Craig

 

[malakilaki]

Okay, you got me interested in an electric impact wrench.

My questions:
1) Craig indicated that a downside to electric impact wrench is a maximum torque of 100 ft./lbs. and I suspect the dealer uses a pneumatic impact wrench, does anyone know if the dealer torques the wheels at 80 ft./lbs. as directed in the Helms manual?
2) I asked the above because if the dealer torques the wheels at a setting greater than the maximum torque of an electric impact wrench then the use of an electric impact wrench is moot. Otherwise, what's a good electric impact wrench and where can I buy one? I presume a 1/2 inch socket driver would suffice.

 

[nwf_snake]

My electric impact wrench is pretty large, and will easily go to 125 lb-ft of torque (that is as high as I have measured with it since my torque wrench only goes that high).
It is a pretty old Craftsman unit I got at a pawn shop for $20!

As an indication of its capacity, I used it to take the front pulley off my '91 Accord when I changed the timing belt. Not a job for the weak! Took a while, but it finally did loosen.

My observations is that 99.975% of all car repair places (dealers down to 10 minute lube places) use an air wrench cranked up to 100+ ft-lbs of torque in order to take lugs off as well as put them on.

I am a little different (read weird), in that I rotate my own tires once a year at home. At this time, I also flush the brake fluid using a cool vacuum tool that I have (more toys)! When I get the tires replaced, the first thing I do when I get home is loosen and retorque the lugs using my torque wrench.

As I mentioned in an earlier post, no warped rotors in this house!

 

[celler]

I'd go with Craftsman like nwf_snake or better yet, Snap-On. Just stay away from fly by nights like the Lugbuster:

http://www.kfor.com/Global/story.asp?S=344690

Even if you pick an electric impact wrench as your weapon of choice, I would never rely on it exclusively. Breaker bars are cheap and it just a matter of when, not if, the wheel gorillas will overtorque your lugs. When it comes to emergencies, sometimes low tech rules.

------------------
Craig