Air hammer blowing air

[seagull369]

Bought a used air hammer at the local flea market. Hooked it up when I got home and, depending on the trigger pull, it either works fine or it blows air. I oiled it repeatedly through the air inlet but didn't seem to help. I disassembled the barrel/removed piston and it looked pretty good (piston slides easily). I didn't see any noticeable seals or gaskets anywhere, but I never took apart an air hammer before, so maybe that's normal. Anyway, I oiled both piston and bore and reassembled but still not much improvement.

Just wondering if there's anything more that can be done with this thing or if I'd just be wasting my time with it. I don't usually buy used air tools, but I got it for only $5 and, since it was a long-stroke, it was kinda worth the gamble.

 

[Odd-job]

Did you try loading it with a chisel? Just bought an aircat 5300 new and it would just blow air through the vent without being loaded. Scared me at first. Works beautifully with a chisel loaded.

 

[seagull369]

Yup, chisel was in there. I also put a long screwdriver all the way down in there and same thing.

 

[emeraldcoupe]

make sure the barrel is TIGHT or it won't work very well

 

[seagull369]

I'll give that a try and put some sealant on the threads, too. The barrel was screwed on pretty tight when I loosened it, tho.

 

[Leaflessshadetree]

Did you press on the chisel (try and cut something)?

 

[Billythekid1]

Yes press on the chisel not just put the bit in

 

[Finky198]

Also to much oil can cause the piston to stick which can blow air pasts the valves.

 

[seagull369]

Yea. I pressed on the chisel and pressed on the long screwdriver when I had it in there, which would have pushed the piston all the way back.

 

[emeraldcoupe]

an air hammer is very simple. when you took it apart did the small disc move freely between the halves when you shake it?

and when I said tight, I mean put it in a vise and crank the barrel down as tight as possible. when I worked at the repair shop, there were quite a few sent in not working that only needed a good tightening.

 

[seagull369]

I'm not sure what you mean by a small disc. If you mean the piston, it slides easily front to back when I point the gun either up or down. There's really only 3 pieces when I took the barrel out: the barrel itself, piston that slides inside, and a cap of sorts on the inner end of the barrel. I'll take a pic and upload. I'll make sure to use a vise and crank down on it when I get to it later.

 

[emeraldcoupe]

I'm not sure what you mean by a small disc. .

the cap you're talking about is two parts, the disc is in between them.

I don't know what you're working on, but see #14 in the link.


https://powertoolrepairohio.com/pages.php?pageid=14&breakid=1670

 

[Zewnten]

Dissassemble and thoroughly clean the barrel, weight and blow out all the little port holes. Don't put any oil in it, tighten the barrel snug and give it a go. If it hits once or twice do it again haha. I had to do it three times to clean up the shops.

 

[seagull369]

I see what you mean. I circled the piece in black in the pic. It doesn't look like it comes apart, but shook it and could hear (and see) that disc you're talking about flapping in there. I'll blow out those holes you mentioned, Zewnten...
Thanks to everyone for all the help so far, btw.

 

[seagull369]

Well, got it back together nice and tight. Worked well for about the 1st three trigger pulls, then did the same thing again. Ticked off, I slammed the side of my fist against the thing and it actually started worked again. I guess I found my key to keeping it going now

 

[bsaint]

Might have to hone the bore some. Prob rust or scoring.