Releasing pressure from the fuel system?

[clarko74]

I'm mid way through my rear end rebuild and it was all going quite well until I discovered this:



Some of the wetness is wd40 on the mounting bolt but on the right it's petrol seeping through the rust/repair.

I wasn't planning on taking the tank out but am going to now. The only way I know to release pressure from the system is to remove the fuel pump relay then start the car, but it's currently got no rear end, exhaust, rear brake lines, etc. Is it ok to start it like this, or is there another way to release the pressure from the fuel system?

Cheers,

[Brianmoooore]

The usual way is to pull out fuse 11 with the engine running, rather than the relay.
You can start the car in the condition you say if you like, but if the car hasn't been started for some time, I doubt if there's much pressure left anyway.
It's no big deal stripping a system that hasn't been depressurised anyway, as long as you're ready for the fuel squirting out of the first pipe you remove.

[daimlerman]

Looks like you have a near-full tank?

Be a bit heavy to remove like that....taking the fuel feed off the rail under the bonnet and replacing with a longer length of hose that will come up over the front wing and down to a suitable selection of cans,then using the fuel pump to empty the tank would be an idea.
Please take great care,fuel moved in this way can create a spark from static,and the fumes are inflammable as well.Plenty of ventilation is needed.

[clarko74]

Cheers for the quick replies. The last time it was started was a week ago, is that enough time for the pressure to drop?

TBH I have no idea how much fuel is left in there, it's been off the road for nearly a year. The fuel gauge says it's about half full, but then again the back of the car is high in the air so I'm not taking much notice of that.

Is using the fuel pump to empty the tank any more dangerous than just siphoning it out?

[daimlerman]

Risk level is about the same,using the fuel pump saves getting a gob full of the stuff!

I have emptied tanks on immobile E30's by using an oil syringe(half litre capacity)from the access hatches on the top of the tank,into gallon containers.

Motor spirit(petrol)is dangerous stuff to handle,most do not realise just how risky it is.This is why the stuff is stored under ground on forecourts,and seemingly silly regulations regarding storing it at home.

[clarko74]

Well there wasn't much pressure left in the system, I have disconnected the pipes on the top of the tank and only a very small amount of fuel came out.

Am I right in thinking that it is only the connections within the hatch:



And the fuel filler pipe that I need to take off before actually removing the tank itself?

[daimlerman]

You will need those other two breather one's off as well,the small breather pipes are fixed to the top of the tank.

There will be pipes to remove underneath,by the filter,just forward of the n/s rear wheel as well.

[clarko74]

Ok, cheers.

Still wondering whether to remove the fuel first then the tank or the other way around.

[mattycoops43]

The fuel in the tank will certainly help it to 'unstick' from the car and drop down.

Talking of how people don't realise how bad it is, I went to the petrol statio yesterday, and as I was walking back to my car saw a guy sitting in the passenger seat of a cabrio, top down, having a fag. I called over "I'm giving you a wide berth then!" and walked as far away from him as I could get, and he just stared at me like he had no idea what I was on about.

Complete prick!

[Brianmoooore]

Perfectly good drain plug on the RH end of an E30 fuel tank. Get an allen key into it and grips around the outside at the same time to undo it.
Your fuel system is an early one with an external pump, so there's no pressure in where you've taken the pipes off anyway.

[clarko74]

I didn't fancy using the drain plug as I only have 16lts worth of fuel storage cans and wasn't sure how easy it would be getting the plug back in once I'd removed it.

In the end I used a bit of clear pipe (that I usually use for my fish tank) and a large syringe and syphoned as much as I could out through the smaller of the pipes in the top of the sender thing in the top of the tank.

Managed to get 27lts out of it and there will be some in there as the rear of the car is still raised up. Had to put the excess fuel that I couldn't store into my other halves french turd, I hope it doesn't disagree with a bit of old petrol!

And no I won't be using that pipe for the fish tank again.

Cheers for the all the advice

[daimlerman]

Fishtank pipe will be fine,once it has vented the fumes,we had to assume spirit fumes remained in a tank for 24 hours,even if a different product was carried in the meantime.

French turds will run on will power alone,just ask Trev(B7) or Rog.!

At least now the tank will be easier to handle and far safer.
Give all 5 fixing bolts a good soak in WD40,they have a habit of snapping if care is not taken.

[Brianmoooore]

Your tank is probably a 55 litre one, with a pipe joining together the two halves at the bottom, so it will drain fully from one side only. If it were the larger 62 litre tank, you would only have drained one side, and would get a nasty surprise when you dropped the tank and found it still very heavy and completely unbalanced.

[clarko74]

It is indeed the 55 litre one with the connecting pipe. It came out without a problem, although the hard fuel lines are past there best so I need to replace them too.