learn me gas tank stuff

hoping to install my new in-tank fuel pump module next weekend. it is this unit: http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=84/mode=prod/prd84.htm

part of the install that everyone seems to have trouble with is the inside of the tank screw retaining ring. a lot of guys have to fight to get it together. I don't want to have to.

I have seen where guys have tack welded the ring to the tank. this makes sense.

my tank is about 10 years old at this point, so is full of gas/fumes/etc. no rust or debris, so that's good. clean, nice tank.

which means its really flammable....

so I see a couple of options here:

1. fill tank with water, tack weld.

2. pray for the best, tack weld.

3. use some sort of fuel proof jb-weld type product.

4. buy two gaskets, pop rivet the ring into the tank. pray that I get a good seal that way.

obviously, id like to go with door number three. makes the most sense to me. but have no idea what that product would be.

what do y'all think? what would you do, and how? why? im more thinking for eventual side of the road pump replacement than initial install. ill have an access hole in the trunk, so it will be possible without dropping the tank.

3 short bolts for each of the two inner pieces to bolt the inner ring to the tank alone, then drop pump in close, use longer bolts to screw in temporarily(maybe +1 to 2in for finger room to remove short bolts). Now the pump and long bolts are keeping rings from falling. Remove small bolts, start installing the final provided fasteners, remove long ones, finish install.

Edit: gasket under pump itself and use something like fuel proof rtv or thread lock on the bolt threads.

It shouldn't be hard to do the above but if you WANT to permanently attach the inner parts I'd fill with water and weld them in myself.

I welded stuff up by the tank of my Jeep(which was open due to the build it was going through) and never blew up, but I'd fill with water if welding INSIDE the tank.

Please do NOT choose option #2.

I would do option 2. Post back after you get out of the ICU.

2 was more tounge in cheek thanaanything. I kinda like living.

And flatlander, that's pretty much what everyone does to install. It would be a pita on the side of the road through the trunk floor though. Which is why im trying to sort out another option.

I have a permatex sealer number for the gaskets and t huh reads.

Dusterbd13 wrote: 2 was more tounge in cheek thanaanything. I kinda like living. And flatlander, that's pretty much what everyone does to install. It would be a pita on the side of the road through the trunk floor though. Which is why im trying to sort out another option. I have a permatex sealer number for the gaskets and t huh reads.

Yeah I reread after the reply and edited my post again.

Fill with water and weld away. Fill it as high as you can without contaminating the weld portion... So you don't get welding dingle berries attached to the inside of the tank.

What about purging with an inert gas like nitrogen? Would be more expensive but less messy then 15+ gallons of water with gas mixed in.

Goal is to drain all the gas from the tank prior to water. And I trust water more than a gas I can't see. I don't really have a sense of smell, so it has to be foolproof.

Dusterbd13 wrote: Goal is to drain all the gas from the tank prior to water. And I trust water more than a gas I can't see. I don't really have a sense of smell, so it has to be foolproof.

I have successfully welded an old tank with water in it. We're talking one from 1965 in 2005. I'm not recommending it, but I'm still here. Have you ordered the pump yet? I saw something really neat in Hot Rod.

https://aeromotiveinc.com/products-page/stealth-fuel-systems/phantom-system/phantom-340-stealth-fuel-system/

...and now, I see the price. Cheap compared to the ER.Or a casket

Last time I did a sending unit in a fuel cell I just got a couple of 3" long machine screws and nuts that matched the threads in the retaining rings. I ran the screws up from inside the tank and out so I could use them as handles for the retainers Once everything was assembled with the rest of the screws I put a pair of nuts on the ends of each of the screws, added a dab of sealant to the threads, and screwed the whole 3" down into the tank.

Obviously I had to make sure that the float wasn't going to hit the screws, but if it ever needed to come apart all I would have had to do is back them out first.

Take the tank and flange to a radiator repair shop most will do tanks. they fill with water and purge with CO2

Big honking ass electric soldering iron

Ummm, Duster, you okay? I saw a post about things you learned yesterday that sounded scary. I'm guessing if you were typing, you were okay. Humbling stuff. I am sorry to have encouraged that.

The problem with backpurging is that there's going to be fuel "embedded" in the tank, so it will always pop a bit unless you're working in a pure zero-oxygen environment.

I've thought about filling the tank with boiling water. Gasoline boils at about 150F, theoretically if you put boiling water in the tank it should get the vapors out of the metal. Maybe. In theory. Haven't had the need to boil sixteen gallons of water yet.

Maybe if you put the empty tank over a bonfire...

Eh. I didn't die.

But, yea, I literally E36 M3 myself. Skidmarked my favorite boxers.

If you decide welding on a gas tank full of water is safe enough, don't.