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Floats

General building discussions, not model specific.
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Swmeek
Posts: 2
Joined: Sun Jan 24, 2021 8:44 am

Floats

Post by Swmeek » Wed Apr 13, 2022 12:53 am

Morning folks - I own the original factory built elite on amphibs. I am trying to find some information about the murphy 1800 floats on it. Are there rebuild kits for the landing gear actuators anywhere? Does anyone know anything about the gear actuators? If not, I need to know the o-ring sizes for the landing gear actuators. Normal AN or MS o-rings still cause it to leak. So it’s some special size?

DocBaker
Posts: 151
Joined: Thu Nov 22, 2012 2:55 pm
Location: Maples, MO

Re: Floats

Post by DocBaker » Wed Apr 13, 2022 5:22 am

I assume you’re talking about the shaft o-ring? If you are using Dexron II you can use nitrile o-rings, but if you are using Dexron III you need Viton fluoroelastomer o-rings. It seems that the synthetic blend of III causes the nitrile to break down. What I have also found is that the actual dimensions vary greatly between manufacturers and also within the same batches for a given size. I get all of my o-rings from McMaster-Carr. The size that works for me is 3/32” x 1/2” x 11/16” but the important dimension is the actual which is stated to be .103 x .487 x .693. I am using two different ones to see which holds up the best. One is a super-resilient one with a hardness of 75A - number 1288N143 and the other is soft with a hardness of 60A - number 1284N141.
It’s been a year on these new ones and no leaks yet

I also use the Viton rings on the retract cylinder and pump cylinder static rings and the brake cylinder pistons
Lindall
Amphib 729R
SPA Field Director MO & AR

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