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Fuel tank questions

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sparkydave

sparkydave

Jedi Knight
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In the process of troubleshooting my fuel pump's inability to draw fuel without vapor locking, I starting focusing my attention on the gas tank, since I had noticed what looked like some debris in the bottom of the tank when I took the filler hose off. Well, since the fuel gauge has been intermittent and I was pretty sure it was the connection at the sender that wasn't working, I dropped the tank yesterday. It looks shiny inside the tank, so I'm not sure if the loose stuff is rust or not. I caught some of it in a coffee filter when I was emptying the last of the tank into my gas can, but it looks more black than anything. So, my first question is does anyone have any thoughts on how to clean the inside of the tank? Second, what would be a good thing to paint the outside of the tank with, since it's a bit rusty?

Last, once I got the world apart and got the sending unit out, it seems like the sender can only get its ground connection by way of the retaining ring, and this would require that the tank be well grounded to the car body. Since the bolts are rusty, the retaining ring is rusty, and I'm thinking about painting the tank anyway, would it be worthwhile to attach a wire directly to the sender and run it to a good grounding point?

-Dave
 
Hello Dave,

last question first, Yes.
You can use spome fuel to slosh around and flush out the tank, let it dry then use an airline to get the last bits out.There are proprietary fuel tank cleaners also available as is anti rust paints, and that is what I paint fuel tanks with.
Finally, check that all venting systems are clear.

Alec
 
Dave,
I've been fighting the same deal every since I bought my '76. The PO told me that he had removed the tank and had it resealed inside but I still have to run a filter before my electric pump. When I pull the fuel filler neck off the tank I can see what looks and feels like black sand in the bottom of the tank and I can only assume that is old rust that was "converted" when he had the tank sealed. I've never been comfortable with it since the fuel filter stopped up on me once already so I went ahead and bite the bullet and ordered a new tank from VB. I should have it by this weekend. I'll snap a few photos of it for you so you can make a decision for yourself what you should do. I've had varied success with sealing gas tanks in the past so I'm going to put on the new tank, clean the lines out, and rebuild the carb. We'll see how it goes. Eastwood company sells a lot of "rust eating" products as well as Moss but like I said I'm tired of messing with this one and hopefully am putting it to bed once and for all.
JC
 
I've coated three tanks over the past few years. I've used commercial products from Kreem and POR-15. Both involve dropping the tanks and acid washing the inside. Of the two systems, I much prefer the POR kit. The chemicals aren't based on MEK (so it's safer) and the POR coating is metallic in appearance so the inside of the tank still looks "uncoated". (BTW, this is POR's tank lining kit... it is NOT POR-15 paint. It's a different, thicker composition designed specifically for fuel).

Regarding the ground on the sender... I've been surprised by the lack of consistency Smiths used on the system(s). The later Mini senders have a ground lug right on the sender mounting flange. I don't believe my Triumph has that lug. However, there is NO reason you couldn't add a ground lug to the flange. If you do this, remember to solder to the steel you'll need to remove any paint and/or clear coating on the flange and use acid flux for the solder to wet the surface. I would avoid attaching the lug by drilling through it... but I guess you could as long as you thoroughly coat the threaded fastener with a non-hardening gasket sealant (like Permatex-2B). Do not use RTV silicone rubber under any circumstances.
 
Dave,

You could check with a radiator shop. Some of them will boil out the tank and then use a sealer for the inside. You can also get "slush sealer" from a small airport maintenance yard once the inside is cleaned out. If they use it in aircraft tanks you can be sure it is a reliable coating. They sell the same stuff through Aircraft Spruce but then you have shipping to deal with (unless you are close to Fullerton California). For the outside of the tank, you should use a 2 part paint as they have more chemical resistance. An automotive paint supply store should be able to steer you right. Just make sure you use proper safety equipment for breathing and skin coverage as the 2 part paints are nastier.

Cheers,
John
 
Hi DK, That is some good advice. That ground if missing should always be installed. However, to install a ground from the sender to the car frame you only need to connect a jumper wire from the sender ring to the closest point on the car chassis.Solder lugs should be installed on each end and only a non acid solder{Rosin Core} should be used.Place a good fitting External tooth washer under each lug before bolting it down on to a bare metal interface.--Fwiw---Keoke
 
Here are some shots of the new tank I got from VB yesterday. The inside seems to be coated pretty well but the outside is bare so I'm going to paint it with some undercoating before installing it. I took low res shots for the forum but if you want high res just ask and I will email them to you. I can't link them all at once for some reason so I am linking them one at a time...
JC

https://xs.to/xs.php?h=xs39&d=05306&f=P7300741.JPG
https://xs.to/xs.php?h=xs39&d=05306&f=P7300742.JPG
https://xs.to/xs.php?h=xs39&d=05306&f=P7300743.JPG
https://xs.to/xs.php?h=xs39&d=05306&f=P7300744.JPG
 
Keoke, try soldering to steel with resin as the flux. It isn't possible unless the part is already plated with tin or zinc.

Use acid flux on the bare steel to "tin" the surface with solder. After you've got a little solder on the surface to tin it, wash off all the residue using brake cleaner followed by ammonia if you want to be REALLY safe. Use rosin flux on the wires and once they're tinned, you can solder them as Keoke said. As for soldering to the bayonet ring, you can do this and it will work, but only if the bottom side of the ring and top of the sender flange are free from non-conductive coatings... and rust.

John, there are some very good aircraft tank sealants. One of my acquaintances in CA uses them whenever he coats a tank. The Kreem and POR products are available mail order through internet sources should you wish to buy products for automotive use. There is no problem shipping these UPS within the lower 48. I'm not aware of any reason the outside of a tank would need better protection than "normal" paints.
 
[ QUOTE ]
I'm not aware of any reason the outside of a tank would need better protection than "normal" paints.

[/ QUOTE ]

I mentioned a chemical resistant paint because it is possible to get a petrol leak around the sending unit or inlet/outlet fittings. "Normal" paints will get soft, wrinkle, etc. and then you need to repaint the tank. Also, in the case of the big Healey gas tank, much of the lower side is exposed to the road elements. My original tank needed replacement because the factory paint was not protecting the outside of the steel and it rusted (the inside still looked great!). With the new tank I'm not taking any chances and I'm giving it the same 2 part paint that the suspension bits and painted brake components are getting.

Cheers,
John
 
Thanks John, I hadn't considered the effects of spilled gas or the possibility of the tank being exposed to the road. I have the luxury of owning to LBCs where the tanks are "inside" and not subject to the road.
 
Thanks all for the info. I've wire brushed the tank and was going to paint it before putting it back in. The inside looks clean other than the little bit of grit in the bottom, so I wasn't going to worry about treating the inside of it. I think I will add a ground lug to the sender body though, and do something to protect the existing lug on top of the sender. Next chore is to take out the rusty fuel line and make a new one, escpecially since I mangled the brass fitting /ubbthreads/images/graemlins/tongue.gif. JC, I take it the replacment tank doesn't have the vent fitting next to where the filler neck attaches? Also, is this the same size as the old one? It seems to me the UK tanks were bigger than the US ones. Not that there's anything wrong with having more gas, but I would hope everything fits okay.
 
It looks like it will fit ok. I didn't get to it today..just got my oil pan back on about a half hour ago. Your right about there not being a vent fitting there. I may have to monkey with the gas cap a little but my tank was in bad bad shape so I am willing to experiment with it. It is supposed to be 7 gallons I think.
JC
 
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