javajeep

Please forgive me if this is off topic. However, this site has been of great help to me as I have learned to make some of my own repairs to my XJ.

This coming weekend, I will be changing my rear brake shoes and -- depending on the condition -- maybe the drums. At sometime in the future, I will likely be doing my front axle u-joints. I know the front hubs have a torque of 175 ft lbs. As I am thinking about these jobs, I am considering an investment in a consumer grade air compressor.

Here is my question, are the relative cheapo air compressors at Wal-mart or Lowes that are selling for around $90 adequate for removing lug nuts and other jobs that that I may occasionally have? I have been thinking about one of those and the prices are hugely variable and I don't know how to judge those. I am not running a shop and don't need anything too big, but I do want something that will operate and impact wrench to speed removing of the lugnuts and wheels and sometimes help me to remove the occasional super tight 175 ft. pound nuts that I may need to remove. Any advice?

mike37

the small compresors will work but will be slower than using a wrench
one or two lug nuts will use all the air and you will be siting wating for it to build presure again

look for the CFM at 90 psi rating on the compresor I wouldnot get one with less than 6

and look at the air reqiurment on the tool then get a compresor with a little more than that

javajeep

Thanks, Mike. This is the kind of information that I need. One of my frustrations is that it takes me about 5 minutes to manually get a wheel off. When I go to the shop, they have it off in about 30 seconds. I would like to be able to do that.

mike37

go look at a good electric impact
bosh dewalt something like that

or from home depot the Ridgid brand has worked well for me on the construction sight and will be a little cheaper

http://www.ridgid.com/Tools/R6300-Im...ench/index.htm

ThumperK15

I got to working on my XJ, and decided to get some air tools. I'll have the tools to use in the feild off my, on board air. It airs to 160-170psi, plenty for tools.

mike37

yes if you ever want on board air then get air tools no need to pay twice

just whatever compressor you get needs to be sufficient run the tools or you will be waiting for it to recoup moor than you are working

ThumperK15

If mine wasn't a trail only rig, then I'd have the on board air out. I just don't need my AC. Now, if you want a good source of air for air tools, and AC, there is a guy on here somewhere with not 1, but 2 AC compressors. That's one for the AC but the other was fabbed in for the "on board air".

4.3L XJ

I have two compressors, besides my OBA. Both are Craftsman. The small one is 1.5 HP with a 1.5 gal tank and cost several years ago about $90. It does surprisingly well. It inflates tires rapidly and will run an impact wrench. However, it will not run it quickly. I have to wait for it to fill the tank a little before going on to the next lug. It will not however take of something with 175# of torque. I keep it in the garage. My shop compressor is a 6 HP 175# two stage. It works great and will make short work of those 175# nuts. Most air wrenches will reach their stated torque at 100 psi. So at 175psi, they really work. So the moral of this story, you can get by with the $90 compressor, but you will not save a lot of time. Also, you will find that these compressors are only 50% duty cycle, meaning you cannot run them continuously without getting them too hot and damaging them. My shop compressor is 100% duty cycle, and I have run it for 30 - 45 minutes straight many times. Another thing is that you really need a large tank to run an air wrench. So you will quickly get out of the $90 range to do what you want.

huntingman2706217

the little $90 compressors are really only made for small nail guns... hints why most come with a nail gun in like a little kit... i have a porta-cable from lowes... 6cfm at 90 PSI and 140 max PSI i belive... but its got a 4.5 gallon tank... also its oil free... I can take wheels on and off all day with it... never have any problems... although with a cut off wheel and if im using it to sand or cut alot of metal it does run the power down alittle but it keeps up... if i let it sit of course it gets alittle faster for a min when i start back... but if i constantly use it the speed is still fine enough for cutting and sanding... i love it and use it all the time (own my own Handymans business)... also i can move it all around easily cause its light and not HUGE!

javajeep

Thanks for all the replies. I really do appreciate them and, I am cooling to the idea of having my own compressor. I was at first excited about an electric impact wrench until I started seeing the prices on those dudes. For that much coin, I can get a compressor that I know will meet my needs.

I went to Lowe's today -- for another reason. The cheapo impact wrenches were rated right around 5.5 to 6 cfm and cost around $40. The cheapo compressors were rated right around 2.2 to 2.8 scfm. One for around $150 was -- I think (but may be wrong) about 3 scfm. To get anything above 4 scfm was BIG money.

So I got home and googled the difference between cfm and scfm. I am really annoyed that the compressors have one rating and the tools another. So -- I am pretty good at math, but also pretty tired and the google results were very technical.

In real world terms -- what is thhe difference between cfm and scfm and why the heck do all the compressors have scfm on the labels and all the tools provide information about cfm????

mike37

scfm is hard to explain
all compresors should give cfm at 90 or 100

6 cfm at 90 psi
is the pump will suply 6 cubic ft of air per minut at 90 psi
if it dosnt give this info its junk

A Standard Cubic Foot per Minute has a specified temperature and pressure of 32F and 14.696

so they are saying that 2.8 cfm at 14.9 psi if its 32 degrees out
not enough to run air tools