Wanner 300 - 4 oil gun

I haven't managed to get my Wanner 300-4 oil gun oil tight. I post a help request on here several years ago, but didn't get anywhere. Oil leaks past the filler cap up the fine threads the pressure is so high. I've made a new filler cap washer using some plastic, all to no avail. I could do with a good clear picture of the component parts as I might have the gun assemble wrong. John

This link to my albums may help:

**LINK**

Rod

John,

The fine threads have nothing to do with resisting oil leakage - only fine to increase sealing pressure as the cap is tightened. The seal is between the gun lip and the ‘gasket ‘- if the gasket (seal ) is a complete circle (not a washer), If the gasket is is a washer, the oil may also leak between cap and washer.

I would be using a resilient gasket material such that it is not overly stretched as the gasket is forced against the cap. A washer type gasket would avoid any stretching and may work more efficiently, even though there are two surfaces to seal.

Starting point is flatness of the lip on the barrel of the gun (assuming the threads are actually parallel on both barrel and cap). Next, be sure there are still threads available when fully tightened (Is the seal actually thick enough). Seal material may need improving.

Many thanks Rod and the other respondent, not done it yet, I'll try again, the gun looks so well made. I didn't know there were so expensive new. John.