Fuel tank sending unit - Bristol 408 MKII
 

Dear Bristol enthusiasts,

I have to change the fuel tank sending unit of my 408. I would like to know how to get access to this device.

Thanks for your answer in advance.

Kind regards and keep healthy.

Clemens Heddier
Coesfeld Germany

Hi Clemens,
If it's anything like the 411, (I think it is), then it is beneath the rear parcel shelf, mounted in the top of the fuel tank. On the 411 you have to remove the rear seat and back to remove the parcel shelf.


Hopefully a 408 owner will confirm.

Fuel Tank sender access
 

Hi Clemens, it is quite an easy job, remove the rear seat base which you may lift out, there are no retainers just a lip ant the front. Having done that you will see two self tapping screws at the base of the rear seat back. undo those, then lift the seat back vertically, it is held in at the top by two slotted clips. when out you will see the tank and quickly remove the parcel shelf and you will then see the sender unit on top of the tank.

Hello Clemens,

Judging by Nick's post the 408 is exactly the same as the 411 in this area - Bristol didn't like to change things if it wasn't necessary! :)

I posted a picture of the hooks on the rear of the seat back in this post http://www.bristolcars.info/forums/8....html#post9788

If the seat hasn't been removed for a long time I found it can take quite a lot of effort to slid it upward so the hooks disengage with the rear bulkhead.

Before you remove the sender unit I suggest you check the wiring.

Please let us know how you get on.

Kind regards,
Kevin

Pictures
 

Hi. Easy jobb. Follow instructionss given given by others.

Regards
Per

My 409 is missing the fuel tank cover plate shown in 408Viking's post. Does anyone know if that should be there on the 409?

Yes the 409 should have the cover plate, I might have a spare one around somewhere which we took off a scrap 603 when I removed the petrol tank, if I can find it I will let you know.
Geoff.

Fuel tank sending unit
 

Geoff.

Thank you. I see the six holes to mount it now.

If the 603 is same as the 409, I certainly could use it. Let me know what you would need for it.

You can contact me at robinlarry(at)aol.com

The guage will show full, ie very extremely full if the sender or its wiring is open circuit and, presumably, empty if is shorted to chassis. I found it impossible to obtain a new sender to the same pattern but, although I cannot now find the invoice, I'm pretty sure that the one I used as a replacement on the 410 came from

https://www.smiths-instruments.co.uk/tank-senders

As you will see there is one hell of a lot of variety, also the resistance patterns vary so I'd suggest getting the Lucas part no off the original or a spares list and asking them to tell you which you need. The in tank bit wil look completely different and you need (I think -I wasnt involved at this stage) to be careful not to get the wires in the tank trapped

While you are at it I'd recommend changing the gasket, obviously, also the breather pipes, the latter regardless of whether they look ok or not.

Good luck, that seat back is a heavy old lump is it not?

The petrol tanks on the 408/410/411 and 603 all look the same so I assume what ever is available would fit all of them. Rogers link reminded me that sitting with a number of other items not opened or used yet was a replacement sender unit I purchased from Bristol Cars before Christmas.
Just opened the box and it turns out they had sourced it from Smiths themselves, Its of their own manufacture 'Caerbont Automotive Instruments' and the reference number is TB9006/KIT, Bristol Cars Label says B.334055 Tank Float Unit 03A03A.
The Carebont label describes the kit as a variable length type, the TB9006/KIT is described as Top mounted, warning light "Bimetal " characteristic and it includes the gasket.

Well done, Geoff, for discerning and establishing order amongst all the chaos; a hallmark of the civil service!

Roger

Yes minister!
Geoff.

The fuel gauge in my 410 has been inaccurate ever since I bought the car. It only shows 3/4 full when the car has been filled to the brim and shows 1/4 full when it is empty.

I suspected the fuel tank sender unit and have removed it from the tank. Sure enough it looks in very poor condition and I have been searching on line for a replacement.

The original part number is FT5301/17. I could not find anything similar on the Caerbont site or on any of the other sites I looked at. Caerbont say they can reproduce them but at quite a high cost for a one off.

Bristol cars may have had some in stock but of course all their stuff has been bought by BOC and it will no doubt be some time before these are sorted out.

Does anyone have any experience of this issue, and hopefully a solution?