Fuel tank removal

I took the fuel tank out last year and had exactly the same issue.

I read up on polymer expansion and left it to dry /air for a week. Not a hint of change.

Ended up 'modifying' (spark free) the lower lip near the floor pan.

Well done Cobber, consider it good cardio vascular exercise along with a little neuro stimulation.

Hi, I'm sure that I also say a write up about how to remove these tanks but again as you say can't find it now. Sorry but good luck, I'm sure you will win!!

Yeah it would seem the numpties didn't allow for the fuel tank expansion when the drew the comics that passed for blueprints!
I've found elsewhere that yes they do indeed expand and apparently they will contract again once the fuel is removed, but.....and here's the good bit....It can take up to  8 weeks!
If ever I meet the bloody moron that made the decision to use a plastic fuel tank in these things......I'll go all medieval on his sorry arse, no torture will be too inhumane for this dipshit!
As for that prick that owns the bloody petrol station he better stay outta my way too, especially as I have both tanks in the Jag to do, I already know how much of a bastard they are to do, I haven't looked at the TR7 yet and that too is a bastard to get the tank in and out of!
NOT HAPPY!

I’m flying by the seat of my pants (Jockettes)on this one. But if you bung up the holes, bar one & apply an industrial vacuum to that, you might reduce its volume by that tad you need for it to pop out.
M

Airportable post=209086 userid=5200I’m flying by the seat of my pants (Jockettes)on this one. But if you bung up the holes, bar one & apply an industrial vacuum to that, you might reduce its volume by that tad you need for it to pop out.
M

 Nah I think you'd need a bit more of a vaccum than you'd  be able to generate with a domestic or even comercial vaccum cleaner,  if I were to go that way, I  suspect I'd be more likely to get results by enlisting physics to help if I could fill it with hot water, seal it, and somehow shock cool it.......it will collapse, but how to do that without crushing it to the shithouse is the question ? Too risky really. And the problem outer dimensions probably wouldn't contract, it would just suck the sides in.
The problem is really one of chemical reaction, I suspect a subtle blend of time, psychology and extreme violence will win out!

I'm wondering if I could employ steam to speed up the reaction by removing the petrol residue in the tank? I have a small steam generator of the type used by dry cleaners.....hmmmmn!
Back when we had the illegal drinking establishment we modified the steam generator of a coffee machine to clean out the beer pipes, worked a treat, we always had the best beer!

Which would be the easiest & quickest experiment to do?
Firstly & most importantly the fuel has to be neutralised, irrespective of the methodology, unless, that is, unless you want to suck petrol vapour up adjacent to a sparking motor.
Half an hour, probably less, would have a blanking plate screwed over the pump hole & an adapter taking the filler pipe inlet to the hose on an energetic vacuum cleaner or vacuum pump.
A glamorous assistant to help & let the magic begin.
It not all that mad cap & after all we’ve covered some far out ideas on here, some as far out as the Kuiper Belt.
M

Getting the tank cold might work (everything gets smaller when it's cold 🥶)

Maybe something like the pipe freeze sprays?

Clearly there are hazards associated with the residual fuel.
So here are a couple of thoughts. But please note I have not seen any MGF or TF tank or looked at drawings.
First, if you can see the rust is it not possible to clean the tank in situ one way or another?
Second if not and you wish to shrink the tank could you blow hot air in (down a hose from something like a hair dryer) and then “close” all openings and let it cool - but watch it cool to make sure it does not shrink too much.
it will probably  cool quickly.
Worth a thought?

Yesterday was a fairly warm day. And plastics do suffer from a great amount of thermal expansion, the trouble is getting a sufficient amount of chiller agent to do the job and the last thing you need is any extra weight as getting this thing out will be hard enough as it is.
Steaming the crap outta the guts of it then maybe purging it with an inert gas like CO2   or N2 , might do it, but all this experimenting is starting to sound expensive, would it be easier to just cut the bastard up and replace it, but off course that would depend on a replacements availability, probably not all that thick on the ground here in OZ, second hand units are most likely next to non existent due to the fact that no bastard can get 'em out, and new ones are probably hideously expensive to to the cost of shipping something of that bulky.

Some years ago the company I worked for had a demolition job at a functioning tobacco factory, It was a fixed price quote, and amongst the problems we had was to demolish a large  concrete bund.... this bastard of a thing was made in a way that I'd never encountered the reinforcing wasn't by steel bar, no it was a random network of fine strand wires a bit like fiberglass pumped through a chopper gun! This stuff was tough sledge hammers hardly made any impact and jack hammers were way to slow and labourious. to make matters worse this bund was located on an upper floor!

What I did was get in an excavator, (what you Poms call a digger) But this came with a whole new set of problems, 1st was one of access, I craned it into the upper floor, with a bloody great crane, then the client quite understandably didn't want diesel exhaust gasses in their still working factory, so I got as much flexible exhaust pipe as I could muster,and attached this to the diesel's exhaust but it still wasn't long enough to reach outside the building so it was in turn attached to some PVC drainage pipe to get the sufficient reach to get the pestulant gasses outside. this Heath Robinsonesque set up actually worked with me dragging the hose and pipe combination around as the excavator worked. 
Well this got us outta trouble, but here is the relevant bit, it was amazing how much the PVC pipe expanded with the exhaust heat it swelled up to a much larger diameter It wasn't to hot to handle with my hands so there was sufficient length of flexible exhaust to allow it to cool with out melting the PVC, but still it swelled to buggery!

Anyway back to the original problem.........I got me some thinking and research to do!
I wanted some mad science thinking to do when I cooked up the K series V8 thread........and now providence has provided some..... the moral of this story is be careful of what you wish for!
And right now, currently my wishes involve thousands of tiny demons with red hot pitchforks tormenting the gentleman's sausage, wedding vegetables and fundamental orifice of both the bastard at the petrol station and the dribbling idiot who came up with the plan to use a plastic fuel tank!

💡⚡️❄️DRY ICE!❄️⚡️💡 That would be both cheaper and more effective at shrinking the tank, than gas, you'd need to let it boil off before trying to remove the tank as it might make the tank too brittle, and the weight would make removal more difficult, but hopefully it would go back to it's original dimensions and stay there due to it's plastic memory.

The use of a plastic tank would've been motivated by the same old reason we have to suffer the fall out of stupid decisions.....Cost!  tooling for roto-molding is much cheaper to make and maintain than the stamping dies for pressing  out metal sheet, and all you have to do is pump the required amount of molten plastic from the extruder into the mold and multi axis spin it to use the centrifugal force in combination with gravity and vibration  depending upon the complexity of the shape to make to hollow form you require, where as you need to stamp out the sheet metal and them weld the two halves and any other shaped features such as the filler tube neck and any double skinning required like the gauge/ fuel pump mounting points, brackets etc. to a fuel tight seal!

Does anyone know exactly what the properties of the fuel tank are, i.e what are the materials of construction/which particular plastic.
I definitely would not use dry ice.
When dealing with rubber lined storage tanks the life span was seriously affected if contaminated with traces of organic materials.
So there will definitely be things not to use.
If "the words of wisdom" passed down the food chain by "the elders" is such that time alone leaves the tank marginally smaller then I can only imagine that the use of copious volumes of warm air passing through the tank will aid that process. But if it is too hot it may have a detrimental consequence.
(Pour boiling water into a fizzy drinks bottle and watch what happens ~ it shrinks and becomes far less pliable).