M-5 Gas Cap

[Kirk]

Parker O-Lube does great and seems to stay slippery for a long time. At my last annual. My IA showed me that ACF-50 also works well, just a small squirt and work it into the rubber. Don’t think it will stay slippery as long, but easy and cheap to re-apply.

I never heard of the short neck/long neck on the caps. Good to know since my 1977 M5 would definitely need short. Did you ask them about just buying gaskets?

Over the years, I’ve had IAs try Citabria gaskets and a few other off the shelf aviation gaskets. None matched the diameter well. All deformed quickly and hardened. Shopping the automotive side, I never found just gaskets.

Kirk

[Kirk]

I'd also love to know if the correct gas cap gaskets exist out there.

I could not find an 'off the shelf' product.

I use NBR BS2751:BA60
It is a Nitrile Butadiene Rubber to British Standard 2751, with a Shore A hardness of 60 degrees
This British Standard meets the required resistance to organic liquids, i.e. petroleum based fuels for gaskets and seals
I had a dozen 'washers' stamped/punched from 1.5mm, 2mm and 3mm thickness sheet, my fuel caps vary in fit.
OD = 60mm and ID = 35mm. Thirty six 'washers' cost £30.
The old washers were removed with ease and the new washers stretch sufficiently to pass over the tabs.
With a dozen of each thickness I am OK for a few years

^^^^^^^^^^^^^^ THIS is a good solution. I’ve been wondering what material would be used. Any of our more technically knowledgeable people know what ASTM standard we could shop here in the US?

[drak130]

On the recommendation of others on this forum, I use EZ Turn. Works well, last a long time, a little dab will do you.

I reapply around annual time. Keeps the gasket looking like new and makes the cap easier to turn (just like the name).

Tim

[PCH]

Kirk asked:
"Did you ask them about just buying gaskets?"

Yes I did. They told me they don't carry them. I could have sworn that i got them from Maule in the past.

Online, I could get a decent match to the diameter but I couldn't find gaskets thin enough.

Like "on final", I found the fit of the fuel caps vary.

Thank you for the Lube suggestions.