Couple of questions relating to impact wrenches. I went to take the tires off big truck (Kenworth) I just bought. I have a 3/4 drive old Black & Decker impact that I have had for years and probably worn some, but it has always removed the lug nuts on my 6000 GMC. I had to take it to a truck tire shop and have them loosen them. He said they should be torqued at 450 lbs. What psi do you run your compressor at for impact wrenches. I looked around for a new one and all the ones I find say not to exceed 90 lbs. I figure I am going to have to bite the bullet and buy a new one. Do you have any idea how many lbs of torque it takes to loosen lug nuts. All my sockets are 3/4 drive so I hate to buy a 1" drive impact & have to buy new sockets. I found a 3/4 that says 1250 ft. lbs of torque. Would that be large enough? The cut off pressure on my compressor tank is 175 and that is what I have used for my impacts.
Proper preassure for impact wrench??
- Thread starter john11139
- Start date
c39er
Well-known member
I always run mine at 150 to 175 lbs and have never damaged any air tools..
Randy in Maine
Well-known member
450 foot pounds is a lot of torque for lugnuts even on this thing.
Call the dealer and confirm that is correct.
Call the dealer and confirm that is correct.
ken w.
Well-known member
I run mine at 130-150 Ft. pounds and my air tools work really good.
A lot of the answer to your pressure question depends on your air lines. The longer they are, the more pressure you need. The smaller they are, the more pressure you need. The more airflow you use, the more pressure you need.
If you're trying to run a 3/4" impact from a 100' 3/8" hose, you'll need to run really high.
If you're trying to run a 3/4" impact from a 100' 3/8" hose, you'll need to run really high.
GYOGI65
Well-known member
Run 150-175 psi but have 1 1/2 lines and 1/2 hose but have an adapter to hook 2 hoses into whip hose .some come off hard, with the bigger stuff volume is as important as pressure .450 to 475 for hub pilot wheels is correct
My air hose is 3/8 and about 30ft long. I know at one time I cut pressure down to 90 and my 3/4 impact wouldn't do squat. So I just run it at what ever my compressor runs at. Do you think a 3/4 drive with 1250 ft lbs would be big enough for truck lug nuts. I don't want to go too a 1" because I am left handed and they have a handle on the wrong side which is not reversible.
Milton Shaw
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- Feb 11, 2011
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NASCAR runs their guns at 450 on nitrogen and only use them one pitstop and then rebuild them . Pressure depends on what you are doing and how long you want your gun to last. Put a pressure gauge on a "T" fitting at your gun and see what pressure you are actually getting when the gun is running. 175 at tank may be just 80 at the gun due to pressure loss.
mopwered
Well-known member
I have ran my air tools at work at 175 psi with no problems it sounds like you have hub pilot wheels and they should be torqued down at 450 to 500 lbs . Your gmc probably has dayton wheels which should be torqued down to 250 lbs which a good 1/2 gun will do at work we always used a 1 in gun you i think ingersoll makes a 3/4 with a extended anvil which would be good for you to use since your left handed .
Have you oiled your impact lately? A little oil in the inlet can make a difference.
General rule is you want 90 PSI at the tool when the tool is running.
You may need 150 or more PSI at the regulator depending on line size and length.
Put a Tee fitting and gauge at the inlet to the tool, then connect your air line and hold the trigger down. What does the gauge say? If you can't get up to 90 PSI by adjusting your regulator, you may need larger lines to the tool to allow more air flow.
If your lines and regulator are not large enough, you may actually see LESS torque with a larger impact gun that needs more air than you can give it.
General rule is you want 90 PSI at the tool when the tool is running.
You may need 150 or more PSI at the regulator depending on line size and length.
Put a Tee fitting and gauge at the inlet to the tool, then connect your air line and hold the trigger down. What does the gauge say? If you can't get up to 90 PSI by adjusting your regulator, you may need larger lines to the tool to allow more air flow.
If your lines and regulator are not large enough, you may actually see LESS torque with a larger impact gun that needs more air than you can give it.
James-W
Well-known member
The air tools I have came with a pressure recommendation. I just follow what the air tool manufacturer recommends.
chris142
Well-known member
The Budd nuts on my Pete were 475 ft lbs per Budd. My 231 took them off with unregulated 120psi off my 20 gallon tank. Could do 5 then wait for air,another 5. Remove that wheel then do the inner ones same way.
Anarius
Well-known member
Our shop lines run at about 170psi, at the tool in use I get about 165. Then again, our shop is run by two fairly large turbine compressors. I've never blown a air tool from overpressure.
As said above, volume is also a requirement of the big guns. I would suggest that you find a larger diameter hose and fittings so you have a chance at delivering all the air the gun requires. If you can check the pressure at the inlet of the gun, you'll find it quite low with a 3/8" hose and 1/4" fittings.
lg
no neat sig line
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justanengineer
Well-known member
JMO but its little wonder you had issues running that impact on that line. At home Ive cheated a bit with small air lines, but at work I've always matched the impact to the air line and run ~110-120 psi at the regulator/drop/air line. Ive been in a lot of truck and heavy equipment shops, 3/8 air lines are kinda rare IME. Normally its 1/2 and either 3/4 or 1 inch.
Does it have budd wheels or hub piloted? Hub piloted wheels most any 3/4 will take off, budd can be another matter all together depending on how often the wheels are off.
If it's budd you want upwards 1,300 ft-lbs... The traditional IR 261 3/4 is 1200 ft-lbs and more often than not you have to get out the 1" to finish the job. An IR 2145 or Proto J175WP will both pretty reliably take wheels off anything. I've only stopped the Proto 2 or 3 times.
Air pressure depends on how big your lines are etc but you'll probably want to be north of 150 psi. More the merrier for changing truck tires
Buy yourself a 1/2" airline and report back, 3/4 and up needs a lot of air