Tweco mig gun liner won't come out

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I'm new to welding. In fact never done it, but wan to make some metal work benches, so it's come time. I bought a used Passport for $700 that came with a Tweco gun. I wanted to refurb the gun and replace the liner, tip, diffuser, etc on it. Model #'s that appear are E180-170 and 35-230cI've got everything apart (I think) but when I try and pull the liner it doesn't come. I was under the impression that it would just slip out as I pull from the end that plugs into the welder (with ring around it).I did try and rotate the feed end, it will spin but not unscrew. Also, it appears as though the gun was hacked to accept a miller plug - should the bare copper be visible on the last pic? This is a little concerning. Should I just replace the gun?Lots more questions will be coming! Attached ImagesLast edited by wheelsup; 02-03-2013 at 02:50 PM.
Reply:There is normally a tiny set screw that holds the liner in on the machine end.My name's not Jim....
Reply:OK thanks, no set screw that I can find anywhere
Reply:Have you tried pushing from the gun end?Ian TannerKawasaki KX450 and many other fine tools
Reply:Look on Tweco's site and see if there are instructions for that model.
Reply:It looks like a real ham fist was working that thing over!Can you pull the slack in from the gooseneck(front end),if so if you lay the gun straight it "should" come out.There should be a very small set screw in the power pin.Check to make sure Hammy didn't run a longer one in there.Someone has taped the back end up but as long as things are not really buggered it should be ok.
Reply:Thanks guys. I did look for a manual by model number but I think this is a really old gun, so no info that I can find online. In fact Tweco's website seemed to be offline every time I tried to navigate to it, and I don't even have a specific model # for this gun accept what I wrote above, and that proved to be useless in web searches.I was going to call Tweco when I get back into town, had to work today and tomorrow. As far as the set screw goes, unless it's in the actual gun part itself (where you hold it) there isn't a single screw that I can find on the unit unless it's under that electrical tape. There was an end cap or plug that I unscrewed, is that what you guys are talking about? But I removed it. It would seem a set screw going into the gun from the side would pinch the lining, not secure it.
Reply:wheelsupThe model is called a Mini Mig, and they are still made.At Tweco, enter Mini-Mig in the search box, and you will have options, plus tech literature with schematics.I've had one on a Miller D-60 wire-feeder for 15 yrs+; it has suffered heavy use and still performs as new.Unfortunately, I can't sight your problem because my gun ison a Miller adapter prong.Mini Migs were one of the early guns to have a screw on nozzle which eliminated the float [movement] between the contactor tip and nozzle.Your gun looks like it has suffered silly-use, but it may still repairable because the body is current production.Keep us posted. Opus
Reply:Ok guys you were right. There is a small 5/64" hex screw in the gun that secures the lining. Got that out and the lining came right out.I called Tweco and what I have learned is that this is a private labeled gun from Century, 160 amp.