Fluorosilicone Shaw Aero 531/431 Fuel Cap Kits

For sale is one complete kit of high quality fluorosilicone o-rings for Shaw 531 and 431 type fuel caps found on many Beechcraft, Cessna, Piper, and Mooney aircraft. Each kit equips one fuel cap and includes the following items: M25988/1-338 3.5″ o-ring, M25988/1-010 small o-ring, a MS24665-298 cotter pin, and a MS24665-132 cotter pin for the bottom of the fuel cap. Use of the best fitting cotter pin for your cap is recommended (some do vary). This kit replaces the following Buna-N (nitrile) o-rings: MS29513-338 and MS25988/1-010.

One kit outfits one fuel cap. If your aircraft has two fuel caps you will need to order two kits, etc.

These fluorosilicone o-rings offer superior durability to help your fuel caps keep fuel in and to keep water out. The small o-ring, which is placed on the handle plunger is commonly neglected and is a source for fuel contamination as water leaks into fuel tanks.  Fluorosilicone o-rings are manufactured by Parker Hannifin to military specification and the current owner of the Shaw fuel cap. Their quality is unparalleled. 

This kit provides standard aircraft parts acceptable under 14 CFR §21.9 for a FAA certificated mechanic to install two military specification fluorosilicone type o-rings on Shaw 531 and 431 style fuel caps. This kit is eligible for installation by a licensed mechanic as a minor alteration under 14 CFR §1.1 and §21.93(a) as it has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness” of the aircraft. No STC, Form 337 submittal or FSDO field approval is required per FAA Order 8900.1 Figure 4-67. A §43.9 airframe logbook entry is sufficient to document this alteration and return the aircraft to service. Also includes an aviation grade cotter pin. Fluorosilicone can withstand a broader range (-100 to 350 degree Fahrenheit) whereas Buna-N has a lower temperature range (-70 to 180 degree Fahrenheit). The manufacturers of the fluorosilicone o-rings are ISO17025 certified. Fuel caps should be inspected for continued airworthiness per your respective aircraft repair manual. 

Why buy here?

• I am an aircraft owner and I fly with my products on my airplane. When I go to fly my aircraft after it has been out in the rain, I am confident that these fluorosilicone o-ring kits are keeping water out and fuel in.
• These are the lowest priced fluorosilicone o-ring kits anywhere and by going anywhere else, you are giving your money away.
• Don’t fall for marketing gimmicks about better quality rings, because there is no scientific proof that different durometer (ex. M25988/3 60-durometer vs M25988/1 70-durometer) offers a better seal. These are the best selling kits available with 100% satisfaction. I have never had a kit returned due to an unsatisfied customer on or off eBay. 
• Thousands of kits have been sold on and off eBay! The proof is in the numbers.

Thousands of kits have been sold on and off eBay with nothing but positive feedback from customers. This is the most complete kit (dual cotter pins) on the eBay marketplace with unparalleled quality. Let the product speak for itself by hearing from some of our satisfied customers:

Mooney owner –  » I had waterless fuel tanks after the heavy rains at both Madison and Oshkosh.  I did however, end up with water in my static system.  I am very happy with these O-rings. »

Mooney owner –  » I put these on a few months ago as I began planning for OSH knowing it’s going to rain. It rained while I was there, not once, but twice. Everything in my tent was soaked, both times. I was a bit worried about water getting into fuel tanks. I was delighted when I took a fuel sample not to see even one drop of water in either tank. I even rocked the airplane a little and then took another fuel sample….nothing! Thanks so much for removing the worry! » 

Bonanza owner – « Installed mine yesterday, o-rings were perfect! »

Baron owner – « Installed them in my 1972 E55 Baron today, super easy and they fit great. Great product !!!!! »

Twin Cessna owner – « AEGIS015 sold me a set for my plane a while back, and the tank that routeinley showed water when sumping is now water free!! I disassembled my caps and installed the new o-rings on my living room floor while watching TV. Easy Peasy. AEGIS015 is one of those vendors who DELIVERS! »