EA81 sending unit gasket........black rubber. Standard EPDM rubber or a special kind? What gasket material will stand up to that application?

hi, 84 parts book shows # 7850 25000 ( exc.elc-mtr ) as the part number , or 7850 25020 (w.elc-mtr ) as the other part number, i dont know what the elc-mtr is about, but the first one shows to fit all vehicles , both gl and dl , and the last one to fit only 4 dr ,wag ,and coupe , designated gl, maybe it's for the digital dash sending units.

Necro bump.

Couldn't find any additional info on this.

Long story short, recently acquired an 82 GL wagon, and this sending unit flange is leaking.

Couldn't find part 7850 25000 or 25020 anywhere so I figured I'd have to make my own.

What do you guys think, maybe get some NBR rubber sheet and cut it out ?

 

Please post back with your choice of material. I am in the same situation with my 79. 
 

I managed to find some rubber bladder type of material and I think I just need to snug my nuts down a bit better. But they are so delicate I sure don’t want to bust one of those tiny studs.
 

Maybe that doesn’t read so well but hey laugh a little. 
 

 

I know silicone sealants generally do not do well with fuel, but, I wonder, I use silicone baking sheet for other areas - wonder how the 0.6mm silicone baking sheet would go in the task you ask ? 

Silicone is a no-go for gasoline applications. The best material I have found is Nitrile rubber sheets (aka Buna-N, NBR, etc.) and it is approved for gasoline and many other oils and fuels.  I laser cut it to make fuel pump diaphragms for mechanical fuel pumps in my older classic cars. You can get plain sheets or Nylon cloth infused sheets if you need extra strength. I've bought from ebay, McMaster-Carr, Amazon and Grainger in the past. Plain Nitrile should be fine for your fuel tank sender gasket. 

Thanks Dave. Seems like what I researched a while back but never made a move on. I don’t have a laser cutter. But one way or another I’ll make it happen. 

5 hours ago, moosens said:

Thanks Dave. Seems like what I researched a while back but never made a move on. I don’t have a laser cutter. But one way or another I’ll make it happen. 

https://www.ebay.com/itm/252846228387?epid=603196425&itmmeta=01HSB670PVVCZXJVBSKKEA3PAD&hash=item3adecf43a3:g:gBUAAOSwTSxkLZeF&itmprp=enc%3AAQAJAAAA4NKeD3UwuBqPJAqm%2BaI8jrZahuIurkzkjCAP%2FQYuObVpZVEqzV%2FMY4GFGFULGvpraxI%2BnjKCaUBHNPfyDSA3LjbhAHdZXIPOc9FA4OCc0N6WWpA6VBTS%2F67%2FA7EqvkMFvWI4or%2FT6faebVgFXYkSMTEHsrqpfaifZOeqIWw0f3MzcxEM7dJQ3TXOjXadfkbMj8OSnrHcQlNiJM3ifprk5gKCxQj8NZfAZxUq%2Fq4cJJY6qlFov78846JvPWNQgADjQn7lknbtGM5ce8BLtu4OC2irZsdKPOgGwhB7NvM0qnmr|tkp%3ABFBM3Iuc5spj

7 hours ago, moosens said:

 I don’t have a laser cutter. But one way or another I’ll make it happen. 

Sure. I'm cutting dozens of my parts at a time in several variations but you can make them by hand. I often use sharpened brass hobby tubing if a hole punch set is not around.

it is an Australian ebay link to the NBR rubber - good for a read or reference

 

Nitrile NBR Rubber Sheet 300 x 200 x 1.5mm Gasket Material Oil, Gasket Sheet | eBay

Hey guys,

Got this all figured out- all good info above.

I ended up going with a Ø3" 1/8" thick Viton disc that I was able to get from McMaster: Gasket Material Disc, Chemical-Resistant Viton® Fluoroelastomer, 3" Diameter, 1/8" Thick | McMaster-Carr

Matched up pretty well with the diameter and thickness of the old gasket, and you don't have to try to cut a perfect circle out of a sheet with an exacto.

(wow I remembered how to use photobucket- blast from the past in some super old albums)

I used an exacto and some hollow punches to recreate the hole pattern and the center opening for the fuel send unit (far from perfect)

Cleaned up the fuel sending unit flange the best I could

Aaaaannnddd... was still leaking. So, I noticed that the little G10 (maybe?) board where the leads are soldered in was rusted good all around, and probably the original source of the leak. Take the sending unit in and out a few times, agitate it, flake off what little rust is holding it all together and more leaking.

So, I took some Tank Weld and filled around the outer perimeter of the board

Been running it like this for a couple months now with no signs of leaks. I can fill the tank all the way up and accurately track fuel mileage now (~ 26 mpg highway with the 3AT, 65 mph ~ 3800 rpms - better mileage than my 94 GT wagon)

Side note- replaced the rear fuel filter this morning (started getting some bucking going uphill- classic symptom of fuel filter clog) and found this

Looks like sand. Was originally a Florida car. Been dailying it since Spring started.