its been MANY years since there was fuel in my gas tank and I wanted to get the tank cleaned out, change the sock etc. before I tried starting this thing.

Well first off the tank looked pretty good inside, with just one spot with rust. so I put in some Evapo-rust and sloshed it around for a couple days, then took a long screwdriver and scraped at the rust, well this uncovered a couple pinholes. there is a tank repair shop near me and they cleaned up the area and welded a small patch on the area and then pressure tested it, all good.

Then I painted it up and decided to change the fuel sock. well when unscrewing the aluminum nut holding the fuel sock in some of the threads remained on the fitting.

so now I need a new nut and also

Does anyone know the size/thread of that fitting? I tried cleaning it up but a fine triangle file just isn't going to cut it without screwing up the threads. So I think I may have to get a die to refresh the threads. and clean out the aluminum..

I don't have any dies that big

https://www.cbperformance.com/product-p/3288.htm (-6AN to VW)

I believe the threads are M18x1.0 size.
http://www.914world.com/bbs2/index.php?sho...p;#entry2104835


Alternately, some have tapped the inside ( http://www.914world.com/bbs2/index.php?sho...&hl=tank+AN )

same thing when I did my brothers tank! you need to find a "thread file" and take your time ..no idea of the thread size or if you can even get a new nut good luck

those thread files are AKA thread chasers.

Had the same issue about a year ago myself. Was told by someone else here on World that the thread is the same as the front axle nut from a mid 90's Nissan pickup. I bought 4 of them - the only way they are packaged - from NAPA. Worked like a charm. Had to use all the nuts as when it pushes out the aluminum material it also looses material from the nut thread. Use lubricant !!
This method worked better than trying to source a die of the correct size and pitch.
Bought new nuts from AA. Buy them both the large and small one.

By the way the seal washers on the bottom of the sock were purchased from the local ACE hardware store. Copper and slightly larger than needed in the OD but they worked.

there's a difference... look it up

Thanks for you replies. When I was looking for my Metric thread gauge I found I had one of those thread files in with my thread chaser kit, I had never used it before.

The thread pitch is 1.0 and the thread file did a pretty good job of cleaning the aluminum out of the threads on the tank fitting. they are in good shape. Then I carefully screwed the nut back on and off a couple times with lubricant and got it to bottom out. about 1/3 of the threads in the nut are gone or pretty thin. it screws down securely, but that is without the pick-up tube and fuel sock/ washer installed. I'll find those tomorrow and trial fit everything again. Think I might still need a new nut though. just to be on the safe side.

I solved that problem by tapping out the inside of the fitting.

it'll probably be ok IMO if you don't over tighten it, there's no pressure there ,,maybe there's some gas prof thread tape on the market ,or just can it and get a new one. Good luck