Pipe needed to trouble shoot

[Project_E30]

I have had picked up on an MOT that my fuel tank maybe leaking. Now I cannot find any holes but I do get a drop of fuel under the tank now and again.

I suspect it is item 15 from below. I took it off and it has small/tiny cracks whcih dont go through the rubber (or so it appears). Now before I buy one from the stealers does anyone have one spare?





I just want to prove that this will solve the problem before I buy parts I dont need.

Cheers

[Brianmoooore]

Not unknown for the hose to fail, BUT it's much more likely that there are rust holes in the metal pipe (11) or/and the tank itself on the metal stub of pipe where the filler hose attaches, or immediately around this stub.
Also, the O ring seal for the fuel pump in the top of the tank often breaks.

[Project_E30]

Cheers Brianmoooore.

What would be your advice?

Been told by a garage that its 4 hours work to change a fuel tank! Circa £160 for labour and £65 for 2nd hand fuel tank.

My only concern is that I change the tank when I only need to change the pipe?

If Pipe 11 was leaking i'm sure I'd see a fuel leak line down it. The tiny drops come to rest on the bottom of the tank under the neck (stub pipe) however I cannot see any holes.

I wonder if its worth cleaning around the stub and using some Aircraft sealent.

Any advice is welcome.

[Brianmoooore]

Fill the tank completely and look carefully for the leak is the obvious advice!
May be a good idea to slide 11 back a bit on the pipe stub first to give a clearer view, and to have some fuel containers handy so that you can drain off some afterwards. Theres a drain plug on the right hand side of the tank, which unscrews OK as long as a) no one's messed up the hex socket before, b) You clean out the socket first, and c) You use a good quality hex driver.
Fuel from a leaking pump O ring also tends to drip down around the area of the stub pipe. To check this one, pull up the rear seat cushion and remove a black oval panel on the right hand side.
IIRC, a new fuel tank is only around £90 from ECP or GSF, so may be worth checking before you go the second hand route.
Nothing difficult in changing the fuel tank (except for access to one particular bolt), but the propshaft and rear exhaust need to come off, so it's not a five minute job.
Your quoted price isn't outrageous, but it's no bargain either.
Check the condition of the rear steel brake lines. They are virtually impossible to change with the tank in place, but relatively easty and cheap to replace with the tank out.

[Project_E30]

I took the cover off thats under the back drivers side seat. It shows no signs of leaking at all around the seal. So there must be a tiny hole around the stub pipe. I'll get under the car and have another look when it stops raining. There is only ever one or two drops so it must be a tiny hole!

[Brianmoooore]

It's not unusual for the stub pipe to have rusted through. I made a permanent cure on one car by derusting and painting everything, and then refitting the rubber pipe with the hose clip as close to the tank as possible.
My theory is that the rusting is caused by the hose clip pulling in the rubber and creating a small triangular shaped space all around the stub pipe between the hose, stub and tank.
Water is drawn into this space by capillary action, and so is permanently wet.
If my theory is correct, then the hose needs to be pushed hard against the tank with plenty of copper grease, and the clip fixed as close to the tank as possible.

[DanThe]

Just replaced mine, the tank itself had rusted through around the joint to the filler neck stub

[Project_E30]

Just replaced mine, the tank itself had rusted through around the joint to the filler neck stub

Dan did you do it yourself & how long did it take you?

Any advice/tips?

Fancy doing it again?

[Project_E30]

I was considering using Aircraft sealent all around the stub. This sealent is used in the fuel tanks of planes so should work.

I thought I may as well try it before forking out on fitting a new one?