Oil Tank Cap Seal

texasSlick said:

@Mark UK

Your tribulations with a seep at the oil filler cap reminds me of mine long ago ....

After much experiment with different gasket materials on the oil filler cap, I finally deduced the oil was coming not from the cap, but from under the "L" shaped mounting bracket spot welded to the oil tank top. This is an issue peculiar to the Atlas and earlier Dommies, but I am wondering if you might have a similar crack where the filler neck is welded into the tank.

You might give that area a careful inspection. A porous weld could produce your gremlin. I hope you get it resolved.

Slick

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Thanks Slick.

I can't see any problems with the tank itself, other than a tiny amount of corrosion in the weld at the return feed. That's not the cause. It was all totally dry yesterday (40 miles, some spirited sections). I had retightened the cap. So I think that's the source.

It's a daft problem, but it pi55e5 me off to have oil everywhere, including the rear disc. I'll just tighten it every stop and hope, in time, the washer mates happily with the cap and I can get it to a point it no longer loosens off. If not, I'll look at either sanding a cork one down, or a different material.

Happily my exhaust header has finally seated where it no longer loosens. I've bent over the retaining washer. So that's one tightening job each stop finished with, to be replaced with tightening the oil cap!

Dumb question time
Are you sure you have the right cap? Mine is labelled Ceeandess, with a sprung centre section where the dipstick is attached. Wondering if maybe someone has fitted an (unsuitable) aftermarket replacement?
Also, is the tank itself sat true in the frame so the cap has no contact with the frame OR the seat when closed? A failing/failed mounting rubber can allow it to shift slightly..

Hi, yes, same markings on the cap. There looks to be plenty of space and no witness wear marks:

But, there is a notch on one of the 'ramps' on the tank lip, which I'd not noticed. I think that is stopping it rotate further. Maybe a needle file in there to smooth that out.

acadian said:

Get your self a leather hole punch set. For larger stuff I'll use scrap bearing outers, bushes etc.. and turn a knife edge on the ID

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Thx. Not gonna work for me as nothing other than hand tools and a drill at my disposal. Plus i've always struggled with scissors trying to make clean cuts and curves. Likely from being a lefty.