O-Rings for 800 fuel shutoff valve

WayneMo

Member
Does anyone really know the right size o-rings that will really seal the tank to valve and valve to stem?? I see several numbers used and wish to find the best ones to use. Everyone that uses this type shut off gas valve needs to find this out. They all fail too soon and can be repaired if you can find the right o-rings.
This forum will do a great service if the right o-rings are known to all. I suspect they are some special sizes. You can repair the valve easily by removing the pin that keeps the stem from coming out too far and replacing it with a new o-ring. Otherwise the new valve costs near $40 after tax, etc.
 
Here's what FIAT has to say about the one at the tank: #87020S92 O-Ring .750'' ID x .070'' Thick, Fuel.

The little one on the shutoff is not shown.
 
As previously posted, I buy fuel valves for 00 and 01 series tractors from CNH.

One of the reasons that I do this is that the CNH valves include the proper O-ring for mounting the valve to the tank. No, I do not know the dimensions of this O-ring but it can (or at least could) be bought
individually from CNH, which I find good insurance.

I've changed many 00 and 01 fuel valves using the O-rings supplied with the CNH valves without issues regarding leakage between the tank and valve, aside from the caveat below.

Caveat: Use of an incorrect O-ring between the tank and valve can and has resulted in both leakage and damage as can improper positioning of even the proper O-ring. An O-ring too large in cross section will
squeeze out between tank and valve, usually leaking immediately or in the future. An O-ring too small in cross section or otherwise mis-positioned will also leak.

Upon leakage, most owners tighten the valve mounting screws. Over tightening these screws can damage both tank and valve, rendering installation of even a new and proper O-ring ineffective.

Use the correct O-ring and don't over tighten the screws.

Dean
 
This is a screen shot of a post on here.
I used o rings from Harbor freight. Been
working fine for 3+ years on one. A year
on another.
cvphoto69483.png
 
My early 4000 has the lever style shut off. I'm trying to make an adapter to replace the shut off completely. It needs another $25 China shut off.
 
I own four of these infamous shutoff valves and the tractors to which they are attached. I got the first one in 1985 when the tractor was already 30 years old. Every 7-10 years the valve needs serviced. 35 years ago replacement valves were readily locally available and relatively cheap. In the 21st century parts for these old tractors are further away, not really that much more expensive adjusted for inflation, and manufactured overseas to sometimes questionable standards, altho in this case I don't see any significant differences between the vintage USA made units and the current overseas manufacture.

I am servicing one today as part of a can of worms I opened with a tractor split. I got this project tractor in 2013, the valve leaked of course, so I replaced it with one purchased from this site. That's the last valve I've purchased. When the next one started leaking I learned how to rebuild them. Really an easy job except for removal and reinstallation.

Here's pictures from today. I had kept all the valves I had replaced over the years and have 4 of them rebuilt and ready to go.

Here's a 7 year old YT unit on the left, Bendix brand in the middle, and Zenith brand on the right. Original equipment? Who knows - the tractors they came off of were 35+ years old before I got them.
mvphoto67590.jpg


mvphoto67591.jpg




mvphoto67593.jpg



Here's the valves with fitted with '115' o-rings, purchased from McMaster-Carr. There are several different formulations of materials available, these are nothing special.
mvphoto67594.jpg


'009' o-ring fitted to the valve. A fatter o-ring would fill the groove more, but it wouldn't fit into the body.
mvphoto67595.jpg


mvphoto67596.jpg
 
The o=ring between the tank and valve. I just grab an O-ring out of my assortment that fits the groove. Never had one leak.
 

Not a commonly found o-ring a -108 will work... If folks would measure out there $5 CHN o-ring they will find its a common off the shelf 10 cent o-ring...

I have installed a few chinese valves even they can not get the o-ring size correct...

Dean -009 and -115 life will be good... : )
 
Cannot see your post clearly. Got a web site number or ytm post source with clear photo? Fuel shut off valve info.
 

I have a follow up to this conversation.

is there enough room between the fuel shut off valve and top of the valve cover to remove the fuel shut off valve? I'm hoping I don't have to take several things apart just to replace the o-rings. thanks for your help!
 
Dave, you'd be best off starting a new thread on this. A lot of the board members use 'classic view' which doesn't bring this old thread to the top with your new post. They will never see your question.

That said, many change out valves without removing sheet metal and fuel tanks. I find it a bigger PITA to fuss in that marginal space than pulling the sheet metal and removing the tank. Your mileage may vary.
 

I have did it the hard way not to my liking. I take the bolts out of the front dog legs them unbolt the tank from the engine and pry the tank up and shim with boards. I did not find it that hard to do.
 

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