sounds like the liner and possably some warn roller feed rollers, the groves can wear if it slips too much. the liners will develope groves inside and these will catch the wire as it feeds through it, also stepping, or kinking the lead will damage the liner too, also as the wire feeds through it rubs the liner and small parts of the wire are rubbed off iside the liner as well as groves wearing in the liner this equates to junk iside the liner that will cause binding as the litter parts break off the liner sides and wedge into the space the wire leaves ineffect jamming it up, you free it up by the hard tug and every thing worksd for a while. also biggest problem is right where the lead gun exits the machine they hang usually straight out then bend DOWn as the weight falls to the floor right there the wire always hits that outter edge of the liner & wears it the worst at that point, and then riolling the machine atround pulling by the lead or worse letting the machine hit a object and bend the lead down even more there.
remove and clean the liners by dipping into a small pan of diesel fuel and then spraying through it with compressed air, followed up by some liner cleaner/lube that comes inb a spray can and is similar to WD40 only it does not have any dieelectric properties which most oils do... so don't use WD40 as that was used as a material everyone can relate to, they also have a smaller HOSE to squirt the cleaner into the lnier with.
mark M
