Fuel tank sending unit - Bristol 408 MKII

[Nick Challacombe]

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.

[Kevin H]

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

[408VIKING]

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

Regards
Per

[LarryW]

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?

[Geoff Kingston]

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.

[LarryW]

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

[PEU186F]

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?