No, the original cap is long gone. I do have a reasonably not terrible
solution that only loses about 1 drop of water per every 10 minutes. At
this point it's become a puzzle I'd like to solve! VW lists 34mm and 35mm
as their options. Clearly I am not the only owner with a tank that takes an
unknown thread size.

On Fri, Jun 28, 2019 at 5:41 PM Stephen Grisanti <bike2vcu@yahoo.com> wrote:

> Do you have the original cracked cap? When that happened to mine I glued
> the halves together and then set that repaired cap into a PVC end cap from
> the HoDepot plumbing department and glued it in place for reinforcement.
> Leak free for years now.
>
> Stephen
>
> On Friday, June 28, 2019, 11:00:26 AM EDT, Jack Elliott <
> pdaxe2gto@GMAIL.COM> wrote:
>
>
> The drain cap for my 84 Westy's freshwater tank developed a crack. The
> online vendors give us two size options: 34mm and 35mm. The smaller 34mm
> (P/N  253-067-285A) seems to be the correct size for this model year, so I
> ordered one from GoWesty.
>
> It's too large, turns without engaging the threads. I double-checked the
> dimensions with their customer service dept. and it's clear that they
> didn't send the 35mm one by accident.
>
> So . . . here's what I'm looking at: a Westfalia OEM water tank (GoWesty
> also looked at pictures of the tank I sent and agreed this is a stock
> tank); with a drain pipe that has an o.d. of 34mm for the unthreaded
> portion; and the threads are in quite good condition with no sign of
> stripping, cross-threading, or wear. Nice sharp edges.
>
> Yet the 34mm cap turns and turns without tightening.
>
> I have a clunky fix installed, using a PVC ball valve from Home Depot and
> it works ... but still, is there some odd smaller-than-34mm size rarely
> seen?
>