71 Charger fuel filler neck issue..

[JOMIDABR]

Just had a new fuel tank put on my Charger and it is leaking when I fill it more than the height of the filler neck right were the neck meets the tank. There is a rather larger black rubber washer around the neck at this location. Any ideas what on what could be causing the leak, given that everything is new?

 

[PurpleBeeper]

Well, I'd guess the filler neck seal you are calling a washer. There is an improved design that fits and seals better. Maybe give the neck a light sanding only in the seal area when you change the seal.

 

[Bb70charger500]

The rubber at the bottom of neck there $8-9 bucks

 

[WileERobby]

If the filler neck seal is old and hard, it will leak.if you change the tank, you should change the filler neck seal.And sock.

 

[71charger_fan]

I put a new tank and filler neck in my '71 and had a hell of a time getting it to not leak. Eventually, I used the improved design with a thin smear of RTV where the outside of neck seal contacts the outer lip of the tank flange and filled the space inside the extra lip on the seal with RTV. It's not pretty, but it doesn't leak. I would love to find a repro fuel sending unit that isn't a POS.

 

[JOMIDABR]

Well, I'd guess the filler neck seal you are calling a washer. There is an improved design that fits and seals better. Maybe give the neck a light sanding only in the seal area when you change the seal.

Thanks PurpleBeeper. I purchased a new seal today and will give it a try.

 

[JOMIDABR]

If the filler neck seal is old and hard, it will leak.if you change the tank, you should change the filler neck seal.And sock.

Thanks WileERobby. Not sure what the sock is....

 

[JOMIDABR]

The rubber at the bottom of neck there $8-9 bucks

Thanks Bb70charger500. You were right $8 bucks

 

[JOMIDABR]

I put a new tank and filler neck in my '71 and had a hell of a time getting it to not leak. Eventually, I used the improved design with a thin smear of RTV where the outside of neck seal contacts the outer lip of the tank flange and filled the space inside the extra lip on the seal with RTV. It's not pretty, but it doesn't leak. I would love to find a repro fuel sending unit that isn't a POS.

Thanks 71charger_fan ...where did you find the "improved design"??

 

[Bb70charger500]

Use seal glide on the rubber I've never had one leak this way . I had a 318 charger as my first car and it only got 6-8 mpg couldn't figure it out the mechanics said it's an old car that's as good as I would get! I later was told every time I floored it tons of cas came out . 8 bucks later I got 20-22 mpg so much waisted gas over this little bit of rubber!

 

[WileERobby]

The sock is the filter on the end of the sending unit pickup inside the tank.

 

[71charger_fan]

Thanks 71charger_fan ...where did you find the "improved design"??

I think pretty much every vendor sells the improved design now.

https://www.yearone.com/Product/chrysler-b-body/fd4182
https://dantesparts.com/shop/mopar-...m-mopar-catalog/mopar-fuel-filler-neck-seals/
http://dalescudashop.com/fufinetotagr2.html

Although, Classic Industries seems to illustrate the old style:
https://www.classicindustries.com/product/1971/dodge/charger/parts/mf297.html

 

[JOMIDABR]

I think pretty much every vendor sells the improved design now.

https://www.yearone.com/Product/chrysler-b-body/fd4182
https://dantesparts.com/shop/mopar-...m-mopar-catalog/mopar-fuel-filler-neck-seals/
http://dalescudashop.com/fufinetotagr2.html

Although, Classic Industries seems to illustrate the old style:
https://www.classicindustries.com/product/1971/dodge/charger/parts/mf297.html

Awesome, thank you very much.

 

[JOMIDABR]

Put the new seal in yesterday. Went in pretty easily. Tried without any RTV first, no leaks so far. Thanks to all who helped with this post. I appreciate it.