# pneumatic grease gun doesn't pump grease



## raylo32 (Nov 25, 2006)

I have an old big chrome plated craftsman grease gun that all of a sudden won't shoot grease. When I trigger it it feels like the piston is vibrating and the air seems to be bypassing it and venting (not out of the relief valve but out of some little vent holes). I am guessing that piston has too much clearance but I took it apart and looks ok. The piston does have a bit of a loose fit but the rubber looks fine and it is well lubed. Any ideas how to fix or do I need to visit Horror Freight and get a new one?


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## Windows on Wash (Aug 30, 2011)

is it air locked? Is there a bleeder on it?


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## raylo32 (Nov 25, 2006)

I don't know for sure but I don't think so. Yes it has a relief and bleeder. Air seems to be flowing pretty freely but the piston just doesn't stroke. I'll go down and mess with it some more today. Luckily I have an ancient little manual gun around that worked for my job yesterday. I had to scoop some of the grease out of the big gun and stuff it into the empty cartridge in the manual gun but I got 'er done.



Windows on Wash said:


> is it air locked? Is there a bleeder on it?


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## raylo32 (Nov 25, 2006)

I went down and played with it some more and got it to work. Just had to dial the air pressure up to about 100 psi. I have a 50' hose reel with 3/8" line so probably need a little extra to overcome the line losses. I thought I used to use it at 60-80 psi but I don't need this tool very often so maybe I forgot?? Or maybe the piston isn't sealing as well as it used to. In any case it needs adequate pressure to fire the single shot piston and if it is too low it just leaks around and out the vent holes.


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## Windows on Wash (Aug 30, 2011)

Piston should be pretty tight and the spring pressure should return the push rod to neutral after you squeeze the trigger. See if the seals are available and replace. Be sure to keep it lubed up as well.


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## raylo32 (Nov 25, 2006)

Yes, the piston seems to fit too loose. On second look it is not a Craftsman and I don't recall where I got it. Also no labels, just "made in Taiwan" etching. Looks a lot like this $29 single shot gun sold by Northern Tool, except mine is red.

http://www.northerntool.com/shop/tools/product_14319_14319


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## Windows on Wash (Aug 30, 2011)

At that point, you are getting close to the repair of it being financially ill advised. 

I thought it was an older gun and the old stuff seems to be worth keeping.


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## raylo32 (Nov 25, 2006)

Yes, with parts, if you can find 'em, and shipping makes no sense to fix stuff like this. I might have to upgrade to the Lincoln "machine gun" model. Overkill for a home mech but cheap enough not to matter.


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