36 gas tank neck help !

Bondolero

Bondolero

Senior Member
My 36 has what appears to be one of the the repro pressed steel gas tanks commonly available. The original filler neck from the tailight is a smaller od than the id of the tank neck and extends down into the tank. The tank leaks when filled between the two pipes creating a real hazard. I have removed the rear fender and spun the neck to see if it unscrews ? it spins freely but will not come out of the tank. Is there a collar inside the tank that has come loose or ????
I am preparing the cut the tube at the neck of the tank tube and use one of the molded rubber connector hoses to span the two diameter pipes.
Am I missing something and will this small piece of tube end up in my gas tank ?

thanks
larry
 
How about a picture?
Getting ready to replace my 35 tank and might have same issues.
Thanks,
Ralph
 
Having experienced a similar but different difficulty, as I was reading your post my mind conjured the same fix which you elaborated further on. I do wish to add, you need to consider a smallish air tube the length of the filler which extends near to the roof of the tank. Purpose to allow air in the tank which is displaced by the incoming gas, to exit the fill tube. Otherwise unwanted gas burps can occur.

Remember, we paid good money to have this much fun!



.
 
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I'd like to see a pic too. Not sure if a 36 setup is the same as my 35. I kept the original tank and had to buy an aftermarket neck...no leaks.
 
there is a loose collar that fits over the gas fill neck, it has threads. you first install a lead washer/seal then the tank neck with the threaded collar into the tank opening, tighten this collar very tight, I had to use a spanner wrench to do this-if it is not TIGHT it will leak. I used a repro tank and an original fill neck
 
Exactly what is wrong. The previous owner did not use the lead seal. Where did you get your spanner ? Mine is new enough it should unscrew. If i can get the neck off without cutting I will cut out a section and have the 2" end put in an exhaust tubing expander and necked out to match the gas tank neck. Then a regular 2 1/2 inch gas hose will connect.
Can accomplish the same with the special formed rubber neck but hate hacksaw the stock neck off at the tank neck. Cant get my pipe cutter close enough. Picture the original 36 neck being inside the new gas tank neck, spins but will not unscrew.

anyone built a spanner out of bolt tips and a pair of expandable side grips ?
 
alanwoodieman said:
there is a loose collar that fits over the gas fill neck, it has threads. you first install a lead washer/seal then the tank neck with the threaded collar into the tank opening, tighten this collar very tight, I had to use a spanner wrench to do this-if it is not TIGHT it will leak. I used a repro tank and an original fill neck
Click to expand...

This is exactly the way mine was but couldn't comment much on a 36 since I had no experience with that year.
 
Bondolero said:
Exactly what is wrong. The previous owner did not use the lead seal. Where did you get your spanner ? Mine is new enough it should unscrew. If i can get the neck off without cutting I will cut out a section and have the 2" end put in an exhaust tubing expander and necked out to match the gas tank neck. Then a regular 2 1/2 inch gas hose will connect.
Can accomplish the same with the special formed rubber neck but hate hacksaw the stock neck off at the tank neck. Cant get my pipe cutter close enough. Picture the original 36 neck being inside the new gas tank neck, spins but will not unscrew.

anyone built a spanner out of bolt tips and a pair of expandable side grips ?
Click to expand...

It almost sounds like you don't have the threaded collar that's part of the filler neck. It screws into the tank and has a lead washer to seal between the tank and filler. If the lead seal isn't there, you can cut the filler tube all day long and splice whatever in it's place and it will still leak. The original filler neck that I replace was obviously tightened in the past with a pipe wrench. I have no experience with an aftermarket tank but I'm wondering if the filler neck fitting might be wrong for your application? A picture will go a long way in getting the answers you're looking for.
 
Are you sure the larger OD pipe sticking out of the tank is not the threaded tube that screws into the tank and compresses the flange on the smaller OD filler tube against the lead washer?

I would try to unscrew the larger tube; you didn't mention holes in the large OD tube in your description; but an original part would have a series of holes around the larger tube to facilitate the use of a spanner wrench.
 
The large tube does as well as indentations on the smaller tube inside. Perhaps I can make a spanner and spin it out. I still plan to use a flex rubber connector between the two to solve the seal problem. Will make a 2" to 2 1/2 short connector out of exhaust tubing and weld on end of original neck. The hose will allow flex between the tank neck and the filler neck ala newer vehicles.
 
got a large pair of slip joint pliers? the spanner I have had for over 50 years. I also forgot to mention that to get it tight enough, I had to let the tanks "float" a little, just loosened the bolts to let tank move around
 
Are those lead seals still available? Or has the state of California determined that it is too hazardous to look at or get within 50 feet of?
 
This is an original neck with a lead washer on a Bob Drake 36 gas tank


picture.php
 
Here's what the original stuff looks like, the flange on the filler neck is the part that seals against the lead washer. The threaded outer tube, by itself, would not seat on the washer properly.
 

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So the washer goes in the tank opening, then the filler neck goes in and the threaded pipe pushes the filler neck against the washer and makes the proper seal? And also allows you to position the neck in the proper place before tightening.
 
I have never succeeded in getting the one in my 35 to seal; I've tried two tanks, I'm currently using a thick leather washer with a loctite product instead of the lead ring, I've got the proper 'C' wrench which I tighten with a length of pipe to increase leverage/torque, and if I fill my tank to the brim, it'll leak every time. Beats me!!
 
I think that is why drake and the others sell this aftermarket rubber connector. Its not like regular gas hose and can be stretched to fit the short neck on the tank, clamped, and then will still connect to the filler tube, clamp, and seal from the neck all the way to the tank.
I believe it was 2015?? product of the year so it appears to work.
Not original, but certainly safer than a leaking gas tank. That can be disastrous ! I was seeking a solution to get the neck off without hacksawing it.
 
The 36 gas tank should not have a neck. It has a soldered and riveted in connector with female threads for the neck with the male threads as shown in the post 14 above. If you were to use a hose between the filler and tank you still need to add a neck to the tank. Maybe you have a later tank with a neck line 37-40???
 
A person might be able to cut out a thin copper washer from sheet copper, or if you have a company in your area that sells hydraulic hose they should also sell fuel resistant hose & rubber sheeting that you could cut out a "washer" to fit in there. I know the rubber is available as my plastic 5 gallon large mouth fuel cans use this type of seal on the caps.
 
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