Possible to repair a 4" Barrel Keg Pump??

I see parts to repair an 8" barrel pump, but not the smaller 4" ones. Anyone aware of a place that sells replacement parts? I guess worst case I buy the 8" shaft and cut and rethread it but wanted to avoid that. Thanks all.

Steve

 

alright, no bites so far. So now I assume I'll just replace the oring. but as there was shredded oring all over the inside of this tap, I washed it out really well (with soap) and am not sure what to use for lube. Keg lube? Some other grease? the beer isn't going into the cylinder so I guess I can use any grease but wanted to check here. Thanks.

 

Silicone oring grease, should be able to find it at Lowe's for a couple bucks. It won't degrade the rubber like a petroleum based grease can and it doesn't break down easily either.