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Usher Fuel Cap O-Rings?

Tracer 10

Well Known Member
RV6 Kit completed in 1994 and has Usher Fuel Caps with Black O-Rings. Does anyone have the AN Or MS number for these O-Rings?
VANS Parts Website says they are no longer available and to buy new fuel caps.
They may not be currently manufactured, although I’ll bet they can be found with a little sleuthing on the internet.
Thanks for you help.
 
Usher does have a website and a parts list from which you can order. Don't have it handy, but google something like "usher machining" or "manufacturing". Also, I think acs sells the oRings.
 
From Vans Aircraft Website.

“Two styles of O-rings have been supplied in RV kits. They are not interchangeable. They are easily identified by color: older O-rings are black, newer ones are brown. The brown O-rings are generally auto fuel resistant, but their tolerance for the newer oxygenated auto fuels is unknown. The older (black) O-rings are no longer available. Upgrading to the newer O-rings requires replacing the fuel cap. New fuel caps with brown O-rings are available and fit all thereceptacles installed in the tanks.”
The O-Rings now provided by VANS, Aircraft Spruce are the newer Viton O-Rings and Vans clearly states that they are not compatible with older Usher Fuel Caps.
Thus my dilemma and question about the AN or MS Number for the original Black O-Rings.
Thanks.
 
Usher does have a website and a parts list from which you can order. Don't have it handy, but google something like "usher machining" or "manufacturing". Also, I think acs sells the oRings.

Here is the contact page for Usher.

They can certainly tell you if it is a dimensional difference or design difference that the new o-rings won't fit.

You can download the parts diagram for the later caps it has the part numbers.

Please post what you find. And use Krytox 205 for lubricant.

View attachment UD-3 Fuel Cap copy.pdf
 
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RV6 Kit completed in 1994 and has Usher Fuel Caps with Black O-Rings. Does anyone have the AN Or MS number for these O-Rings?
VANS Parts Website says they are no longer available and to buy new fuel caps.
They may not be currently manufactured, although I’ll bet they can be found with a little sleuthing on the internet.
Thanks for you help.

They are Std oring size 326

I bought Viton replacements here:
https://www.oringsandmore.com/viton-fkm-black-o-rings/

If your particular about MS or AN specs, you can pay a little more and get (BUNA not Viton) here:
https://www.aircraftspruce.com/catalog/pnpages/AN6227B-29.php

And I strongly endorse Bill’s suggestion to lubricate with Krytox. Stuff’s not cheap, but you don’t need much.

Peter
 
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Thanks for the information.

I really appreciate finding what actual p/n’s are for older usher fuel caps.
Thank You.
 
Small diameter O-Ring for center shaft on Early Usher Fuel Cap.

I really appreciate finding what actual p/n’s are for older usher fuel caps.
Thank You.

Peter,
Since you came up with the part number and source of supply for the large O-Ring. Any chance you have the part number for the small center shaft O-Ring?
 
Peter,
Since you came up with the part number and source of supply for the large O-Ring. Any chance you have the part number for the small center shaft O-Ring?

The small one is size 011. (Same size as used in the fuel drains typically).

Also available at oringsandmore.com (in BUNA or Viton).

Peter
 
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Peter, Since you are batting 1,000 I have an O-Ring Question?

The small one is size 011. (Same size as used in the fuel drains typically).

Also available at oringsandmore.com (in BUNA or Viton).

Peter

I have an older RV6 with the Usher GAS-5 fuel sediment/filter bowl.
The O-Ring that was installed is obviously the wrong size and is seeping fuel under pressure from the electric fuel pump.
To you have a AN or MS number for the correct O-Ring.
Thanks a Million.
 
I have an older RV6 with the Usher GAS-5 fuel sediment/filter bowl.
The O-Ring that was installed is obviously the wrong size and is seeping fuel under pressure from the electric fuel pump.
To you have a AN or MS number for the correct O-Ring.
Thanks a Million.

I don’t have an Usher Gascolator on my RV, so I don’t know the proper O-ring size. It looks like Vans sells them however... try here:

https://shop.vansaircraft.com/cgi-bi...duct=gas1parts

That same page offers the replacement screen as well in case you need that.

If you measure the new o-ring carefully (OD, ID and thickness) there is a size chart at Oringsandmore.com that will tell you the numerical size designation.

Good luck,
Peter
 
Usher Fuel Cap - O-ring part numbers

ACS - aircraft spruce and company

O-Ring 2-012 Small for Usher Flush Fuel Cap Spruce Part# 05-02147
Usher Part Number #50


O-Ring 2-235 Large for Usher Flush Fuel Cap Spruce Part#05-02146
Usher Part Number #70
 
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