Gas Cap, part 2

[steven m]

Cleaned the gas cap and gave it a dose of medicine, WD40, and everything works, including the lock and the ratcheting feature.  Heh heh heh.  Is there supposed to be a large 0-ring style gasket at the base of the threaded barrel?  Hard to tell from the factory parts diagrams
Thanks
Steve

[Bob_Roller]

WD40 turns into a sticky varnish with time, I would get a light oil in there instead .

There is a rubber seal at the base of the threads, a fuel resistant o-ring would work, the OEM part is around $6US .


http://www.realoem.com/bmw/showparts.do?model=0364&mospid=51897&btnr=16_0228&hg=16&fg=11

Item # 17 .

[steven m]

Aha, I thought so.  I have some light oil for electronics, actually sewing machine oil, I'll use that.
Thanks
Steve

[Barry]

Is there supposed to be a large 0-ring style gasket at the base of the threaded barrel?Hard to tell from the factory parts diagrams

I don't know if all sources of replacement seals are the same but there have been reports of the cap not fitting correctly when a new seal is fitted due to the profile having changed from the original. I recall that instead of a simple L shaped seal some new seals have an additional lip which can prevent the cap screwing down far enough allowing the two parts of the cap to rattle.  It may be that not all caps are affected. A forum search should turn up some previous threads on the subject.

I can tell you that a large O ring with approximately 40mm ID and 4mm cross section works surprisingly well as a substitute.  The commonly available Nitrile rubber O rings that are provided in the boxed O ring kits are reckoned to be rated for fuel but I find they soften after a few years. Hardly an issue when they cost pence.

[Mike V]

Steve,

Back in late 2011 we had a thread going about the replacement seal for the gas caps.  The replacement looks to be a mis-fit even though it does work in sealing the tank the new replacement seal will make your cap sit proud of the tank opening a bit.  Here's the link I was referring to and the part number associated with the gas cap gasket and the upper rain seal.

http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1319022133

[montmil]

I shopped the plumbing O-ring section at Ace Hardware & BMW Emporium. Found an O-ring for cheap that was the correct diameter but with a skinnier cross section.

It worked, as Lucky Lou would say, sweet as a nut.

[steven m]

Great minds must think alike.  I went to my local Ace hardware store yesterday morning and in the plumbing section found a flat gasket of the proper size, for less than a dollar.  Works just fine and the gas cap is flush with the tank and properly aligned when closed.  

Thanks for all of your input.

Steve

[montmil]

"Great minds must think alike.  I went to my local Ace hardware store yesterday..."
 Â    - Steven M

As Hannibal would say, "I love it when a plan comes together".
 Â    - Hannibal Jones, not Lecter