Check your gas cap o-rings

little wing · Posted: Fri Oct 18, 2019 5:41 pm Post subject: Check your gas cap o-rings

On our last trip, the marina gas pump attendant noticed the gas cap o-rings were quite deteriorated. Both gas caps as well as the water cap looked the same. I'm sure these are original (2005) and it's obviously time to replace them.

Replacements are 2/$12.49 at WM.

These are the same and available for $0.79/ea at Ace Hardware.

tsturm · Posted: Fri Oct 18, 2019 5:48 pm Post subject: Re: Check your gas cap o-rings

thataway · Posted: Fri Oct 18, 2019 9:03 pm Post subject:

Great reminder, and I have been eying my O rings on both the fuel and water caps. You want to be sure that the "O" ring is resistant to gasoline for the fuel tank. Also resistance to UV and Ozone is important. I tend to favor FKM/FPM/Viton™ (Flurocarbon) over the "NBR" or Nitrile O rings. Any "rubber" which is not one of these is probably not the best choice for longevity in the fuel environment. Ethylene-Propylene / EPDM:is not resistant to gasoline. The Vitron is going to be a bit more expensive. On the other hand, West Marine charges $12.95 for two "Perko" O rings which are listed as "rubber". Wholesale Marine has "Sea Dog" O rings for $1.27 each...but again don't list the composition of the material. Grainger has the 1 5/8 OD in Nitrile at about 10 cents each, Viton for about 40 cents each, and Silicone for about 20 cents each. These prices are all in packs of 25. Can you say "marine markup"?

I like to keep my fills clean and a light coating of "Superlube O Ring silicone Grease" on the o rings and threads.

little wing · Posted: Fri Oct 18, 2019 9:25 pm Post subject:

The o-ring in that bag is nitrile. It is compatible with gasoline...and water.

thataway · Posted: Fri Oct 18, 2019 9:26 pm Post subject:

Thanks--I didn't see that on the package. Sure cheaper than West Marine!

C-Green · Posted: Sat Oct 19, 2019 10:55 am Post subject: Danco o ring at Ace

According to the Danco website the #50 o ring is made of "Durable rubber construction". So is nitrile a rubber? Not trying to stir the pot, just trying to get a gas resistant o ring.

Jay

localboy · Posted: Sat Oct 19, 2019 1:05 pm Post subject:

thataway · Posted: Sat Oct 19, 2019 1:25 pm Post subject:

Description of Danco #50 O ring:

C-Green · Posted: Sat Oct 19, 2019 10:09 pm Post subject:

Dr Bob and Localboy, Thanks for the clarifications. Where did you find that description of the Danco o ring?

Jay

thataway · Posted: Sat Oct 19, 2019 10:35 pm Post subject:

C-Green · Posted: Sat Oct 19, 2019 10:50 pm Post subject:

Dr Bob,

Thanks again. C-Brat site is invaluable with your help, the administrators and other contributors.

Jay

localboy · Posted: Tue Mar 03, 2020 6:42 pm Post subject:

Old thread:

The o-rings pictured above do fit the water & waste caps but both our fuel ones are much larger & thicker. I'm going to try to find them at Ace also so I don't have to pay $6 each.

little wing · Posted: Tue Mar 03, 2020 7:05 pm Post subject:

On my 2005 CD22, the fuel and water caps are the same (except for the external fuel/water markings) and use the same o-ring.

Marco Flamingo · Posted: Wed Mar 04, 2020 12:46 pm Post subject:

I had a great experience at O-Rings West in Lynnwood. Although clearly geared as a commercial wholesale supplier, they took the time to analyse an old o-ring and sell me two new ones for a dollar when the OE supplier wanted $30 each.

Based on what I learned, I recently measured and bought a "kit" for rebuilding my vintage Wagner 701 hydraulic steering. $4 at Ace instead of $29 for the increasingly rare "official" rebuild kit (which does include a paper gasket). I just happened to have a "ring mandrel" from another project that really helps quickly measuring ID on smaller o-rings. OD is simply adding twice the o-ring thickness measured with a caliper. Easy peasy.

The most difficult part was that the little bins at Ace were a mess based on customers mixing up the sizes (plus metric mixed with imperial). I lucked out after close examination, but I should have taken the mandrel and caliper to the store. That would have saved me 10 minutes of tedium.

Mark

https://www.amazon.com/Rosenthal-Collection-Ring-Sizer-Mandrel/dp/B01MG5HOEO/ref=pd_sbs_261_t_0/133-5166576-4422325?_encoding=UTF8&pd_rd_i=B01MG5HOEO&pd_rd_r=8286e083-87de-46d6-84dd-349ec2617c44&pd_rd_w=JHSGh&pd_rd_wg=HRyKK&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=TD7BCAQN9BHY6BKTZ1DX&psc=1&refRID=TD7BCAQN9BHY6BKTZ1DX

journey on · Posted: Wed Mar 04, 2020 12:55 pm Post subject:

OK, I'm confused. What are the O-ring OD and ring thickness? For both the water and gas caps.

Boris