Compressor Question
 

I just bought a Sears Craftsman 3 gal./125 psi compressor and I am amazed that it cannot fill a truck tire. What am I doing wrong? I turn the compressor on, allow the tank to get to 80-100 psi. The regulator valve is set so I have the same amount of pressure at the tire chuck. Yet when I put the chuck on the tire, the compressor seems not to have enough "umph" to top off the tire. Did I buy a compressor that was too small, or is there an obvious problem, either mechanically or in the way I am using the unit? The unit came with a tire chuck, so I assume it should be able to raise a truck tire from 18 psi to 35 psi. Mine will just sit at 18 psi. There are no leaks in the system. As I said, it seems that the compressor just does not have enough force to do anything more than fill a bike tire. Any suggestions are more than welcome-- even if it is to tell me that I'm an idoit. Thanks. H.

87 4R
95 4R
Bethesda, MD

Does the pressure in the tank drop when you do this?
If not then you are doing something wrong.

Got a pic of your setup?

Are you sure that the regulator is set, and functioning properly? Also check that the air chuck is working. As for the compressor, that plenty to fill a tire

Thanks for the follow-up questions. The pressure in the tank does not drop when I apply the tire chuck to the tire, although it will drop when I manipulate the chuck by hand. So when I have 100 psi in the compressor tank and put the tire chuck on my tire that has 18 psi, nothing happens. It is as if the pressure in the tire is suffiicient to counter act the pressure in the tank. When I put the same tire chuck on my mountain bike tire, it fills it easily. I believe the regulator is working because when I dial it back it releases pressure from the tank.

I don't know if the link will work, but here it is:

http://www.sears.com/sr/javasr/produ...s+Under+%24100


Sounds like I may be doing something wrong. I may have to temporarily turn in my man-card and take the damned thing to a gas station and ask for help in figuring this out. My wife will love that.

oh no, dont get a punch in the card yet, ... may sound stupid, but compare your valves between your bike and your vehicle, also, have you tried all 4 tires? maybe a tire valve is plugged? Ever used that green stop leak stuff? (don't) maybe try your spare too after other tires, that will be a diff age and may have a diff valve, or try a diff car....

Just spoke with a tech advisor at Midwest Air Technologies, who makes the compressor for Sears. Apparently, my 3 gal. unit *can't* fill a light truck tire, which holds about 14 gallons. I'll test it out on my wife's car tires--m which should be easier-- but the tech thought I'd have much better luck filling a 10.5 x 15 x 30 tire with a 5 or 7-gallon compressor as a minimum. Oh well, I may have wasted $100 in buying the wrong kind of compressor (purchased on eBay no less, so no chance of returning it to Sears). H.

I have filled some rather large tires with a smaller compressor than you have there (12v cheapo road side inflator) . You need to try it on someone else's tires or ask the guys at the tire shop to help ya out cause you must be doing something wrong. I don't think that compressor will air up multiple tires very fast but it should get at least one done in a reasonable amount of time. Your air tank gauge should drop very quickly and your compressor should start and continue to run in an attempt to keep up eventually filling the tire. You may have to stop and wait for the compressor to catch up once or twice per tire but that should take very little time based on the tank size.

I have a tiny 2 gallon air compressor and it fills my 31's just fine. I do notice that if the unit is not directly plugged into an outlet that it will not function properly. Are you using an extension cord?

i going with a plugged valve stem. and that tech guy has no idea what hes talking about, that compressor is plent strong to fill tires. if it can pressurize a steel cylinder to 125psi or more, it can pressurize a rubber one to 35! it may have to run for a bit to get the volume of air, but thats still not an issue. It must be something that is preventing the air from going into the tire. try and let air out of that tire and see what happens.

I had problems when I first got a compressor. The chucks they give you are cheap.
The don't line up with the valve stem on the tire very well. Play with it a little till you hear air coming out.

at least that was my problem..a cheap chuck.

Thanks again for all the recent responses. I haven't had any better luck filling my truck tires. The compressor works fine on my wife's dinky Audi tires. I've replaced the chuck twice, and I still haven't had any luck filling any of the tires on my 95 4R, 87 4R, or 94 4x4 truck (all 31x10.5x15), so I'm assuming that's not the problem. I am using an extension cord-- but I guess I don;t understanbd what efefct that might be having. As I said earlier, I can fill the 3 gallon tank in under a minute so that it reads 120 psi. It;s just when I apply the chuck to the truck tire, there is a small hiss, as if some air is going in-- but then it just stops dead. no movement of air into the tire. I really do appreciate the suggestions. I have better results plugging in my tiny/no reservior tank inflator than I do with the comparively burly Sears compressor. It leaves me with two possibilities: 1) I don;t know what I'm doing or 2) something is wrong with the compressor. Thanks again. H.

the extension cord thing: if it is too thin of guage (they always are) there will be too much drop and the compressor will not start, this is true with all high current tools... you will of course have to leave the compressor close to the outlet and plugged in for it to work, if it will....

There is nothing wrong with the compressor.... I've seen in some cases, the valve core in the stem were sunk in too deep, preventing the air chuck to access them, this sounds like the problem your having.

As for the extention cord, that is a non-issue if the tank is filling up.....

Bruce sounds like he's got the right idea. Verify that the chuck is actually depressing the valve. I once had to grind off some of the threaded portion of a tire valve to make a gauge work on it...although that was a shade-tree solution to a cheap ass gauge.

Update: There are a lot of smart people ojn this forum-- or at least in this thread (and that doesn't include me). The tire chuck was indeed the problem-- but it took four different chucks before I found one that actually worked. The three that did not work all came from Sears, one that came with the compressor and two purchased separately. Each chuck would give an initial burst of air when placed on the valve stem, but after that went "dead". I finally borrowed a chuck from a gas station and it worked perfectly. Thanks for leading me in the right direction on this. No thanks, surprisingly, for Sears tools, which I always thought had such a good reputation. Oh, well, live and learn-- or at least live and then ask the learned group on this forum. H.