R33 Fuel Tank crack

[Blakeo]

Hi Dose, I know you'll be reading this thread. Brake pads are going good mate thanks.

Anyway, pulled the 33 fuel tank out today because we were limited to a disgusting 480hp on the old fuel pump setup.

On pulling the tank, I found the cracks in the photo (I don't think they're leaking, but fuel evaporates quick so hard to tell).

What's the best way to repair, or is their a new tank alternative?

Thank you.

[Dose Pipe Sutututu]

I personally haven't been in this situation, however have repaired a cracked radiator using JB Weld and held up until I could replace it with a Honda Accord years ago.

Maybe @GTSBoy might have a sound strategy?

[GTSBoy]

I'm not that familiar with R33 tanks. Plastic? Up behind the rear seat between the towers? Or under the boot floor like a normal car? It's the battery that's up between the towers isn't it?

So, plastic tanks. Well, um. The obvious reco is plastic welding, which you'd only look at asking someone who's really good at to contemplate trying. The fuel contamination and grot is probably going to make it quite difficult though.

Whether plastic or steel - the end of the crack will want to be drilled before any welding or sealing is done. Otherwise it will just continue to wander along until something bad happens.

Steel tank? The obvious answer is drain, wash, purge with inert gas and drill the crack end and weld/braze/silver solder/whatever the guys who do that to fuel tanks recommend.

I had a crack/hole/leak in the bottom of a Commodore tank (oe was it my ALFA? - can't remember) that I slammed some gorilla snot onto and it never leaked again. It worked surprisingly well.

Or, it's time to fab a new tank.

[joshuaho96]

19 minutes ago, GTSBoy said:

I'm not that familiar with R33 tanks. Plastic? Up behind the rear seat between the towers? Or under the boot floor like a normal car? It's the battery that's up between the towers isn't it?

So, plastic tanks. Well, um. The obvious reco is plastic welding, which you'd only look at asking someone who's really good at to contemplate trying. The fuel contamination and grot is probably going to make it quite difficult though.

Whether plastic or steel - the end of the crack will want to be drilled before any welding or sealing is done. Otherwise it will just continue to wander along until something bad happens.

Steel tank? The obvious answer is drain, wash, purge with inert gas and drill the crack end and weld/braze/silver solder/whatever the guys who do that to fuel tanks recommend.

I had a crack/hole/leak in the bottom of a Commodore tank (oe was it my ALFA? - can't remember) that I slammed some gorilla snot onto and it never leaked again. It worked surprisingly well.

Or, it's time to fab a new tank.

It is a very complicated plastic tank. Sitting between the rear seats and the rear subframe. Requires a siphon venturi pump in the hat to suck the fuel from the passenger side to the driver side of the tank. The answer is probably prepping the tank very carefully to eliminate all fuel fumes, drilling any cracks to stop propagation, then plastic weld. I don't really see any other solution here. 

[Duncan]

which is to say....can be done but probably a specialist thing.

My guess is the tank was dropped with the breather still connected at some stage, there's no reason it would crack on top of the tank on its own.

[WMDC35]

Replace with a used tank?

[Blakeo]

Seems to be a common issue, I had a look at two used tanks and both had similar cracks to mine.

No one that does plastic welding near me seems to want to do it to a fuel tank lol

[Blakeo]

Got lucky and bought a new s14 tank thru enjuku, hurt a bit but no more cracks.

[Dose Pipe Sutututu]

Hopefully will last another 30 years