Fuel tank leak

[LewisH]

Hi all,

After experimenting with the Exmo this week, I have found that the fuel tank is leaking around the sender unit. I then tried to tighten up the 6mm nuts that hold the sender unit in place, only for one of the threaded bars that is welded to the tank to come off in my hand! 

As I don't fancy tying to weld aluminum, I am now looking for a new fuel tank. Are these standard across the Robin Hood range? Can anyone suggest an affordable option? I have looked on kit spares and they are £180, but don't seem to have any provision for the sierra sender unit to be fixed in place.

Edited June 21, 2022 by LewisH

[IanS]

The tanks that came with the kit were stainless so if you have an alloy one this is non standard.

Edited June 21, 2022 by IanS

[IanS]

You could use rivnuts.

https://www.amazon.co.uk/Proster-Riveter-Riveting-100pcs-Setting/dp/B08G4HB77F/ref=asc_df_B08G4HB77F/?tag=googshopuk-21&linkCode=df0&hvadid=463094615488&hvpos=&hvnetw=g&hvrand=5465414145904340091&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046452&hvtargid=pla-990128104932&psc=1

And make a gasket

https://www.amazon.co.uk/Nitrile-Bonded-Gasket-Material-Various/dp/B09J453KGZ/ref=sr_1_7?adgrpid=104837889118&gclid=EAIaIQobChMIrdHQlei--AIVYIBQBh2t2gD4EAAYAyAAEgLslPD_BwE&hvadid=446600911396&hvdev=c&hvlocphy=9046452&hvnetw=g&hvqmt=e&hvrand=17700559792586579682&hvtargid=kwd-338760600434&hydadcr=20940_1721524&keywords=gasket%2Bsheet%2Bmaterial&qid=1655823891&sr=8-7&th=1

make holes in the gasket to just clear the rivnut insert.

A smear of blue hylomar on both sides of the gasket should help seal.

https://www.amazon.co.uk/Hylomar-Universal-Gasket-Jointing-Compound/dp/B079D8XJSP/ref=asc_df_B079D8XJSP/?tag=googshopuk-21&linkCode=df0&hvadid=430753776182&hvpos=&hvnetw=g&hvrand=717522071671627354&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046452&hvtargid=pla-909559816250&psc=1&tag=&ref=&adgrpid=103698421881&hvpone=&hvptwo=&hvadid=430753776182&hvpos=&hvnetw=g&hvrand=717522071671627354&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046452&hvtargid=pla-909559816250

[agent_zed]

When I built my tank I cut out the shaped hole from the sierra tank that the sender goes into. I then riveted and araldited (as its petrol proof) it to my tank so i could fit the sender unit in the same way it had fitted in the sierra tank, by just twisting and locking into place.

Been like it for 10 years without a problem.

Not sure how easy it would be to make the correct shaped hole to accept the sender but if you could the sender would then use the correct seating face and be easy to remove in the future as needed.

 

 

[Jez Morton]

The tank on my early S7 did the same studs snapped off. I also found the tank too thin to support a gasket under the sender so it would leak between studs. I made a ring of stainless with studs attached to go inside the tank (needed a slot in ring to get it in). Fitted that with a gasket and a rubber gasket under sender, sealed it OK.

[LewisH]

I like the idea of cannibalising the sierra tank to fit onto the RH one, the cheapest one I can see on ebay is starting at £60...so I'll try rivnuts first and see how it goes, it's a tool I don't have currently so an investment if nothing else.

If it still leaks I'll go down the sierra tank route or try and fabricate something like Jez. 

Many thanks for the suggestions gents

[2bTom]

I have a fuel tank that is for sale if you are intrested.

https://www.rhocar.org/index.php?/forums/topic/50181-robin-hood-2b-parts/#comment-408946

 

[LewisH]

9 hours ago, 2bTom said:

I have a fuel tank that is for sale if you are intrested.

https://www.rhocar.org/index.php?/forums/topic/50181-robin-hood-2b-parts/#comment-408946

 

Ah ok yes definitely. I assume that the sender unit hole is to fit standard sierra unit?

The main concern I have is whether it will fit in the exmo. Would you be able to send me some basic dims of the tank and also dims of where the holes are for sender & filler? The exmo has pre-cut holes in the monocoque that need to match the tank roughly. 

[2bTom]

Sorry about my drawing skills hope this makes sense to you. All the dimensions are in mm it is probably easier to compare the picture to the drawing.

[LewisH]

On 6/22/2022 at 8:44 PM, 2bTom said:

Sorry about my drawing skills hope this makes sense to you. All the dimensions are in mm it is probably easier to compare the picture to the drawing.

 

 

 

Unfortunately this is much smaller than the exmo tank and the holes for filler & sender do not line up. I've just taken the tank out and mine is 860mm wide...rivnut tool has arrived though so I am going to go down this route.

Thank you for going to the efforts of the drawing though, much appreciated. 

[2bTom]

Ok no problem. Hope you get sorted.

[Snapperpaul]

I put drilled flat bar across pairs of studs to spread the load and stop the tank/sender mating surface from warping