Fuel tank sender unit question

[Sterly]

I'm currently helping a friend get his 411 on the road and the fuel gauge permanently reads empty. Can anyone tell me where the sender unit is located and how to access it?

Thanks in advance, Mark

[GeorgeG]

Mark
I am working on a 408 which should be much the same as the 411. If it is, the fuel tank is behind the rear seat and below the parcel shelf. From recollection, I removed the parcel shelf, which revealed the top of the fuel tank. There are 2 "removable" items on the top. One is the Fuel Reserve Unit and the other (I think it is round) should be the float unit. If you have a problem, let me know and I will send you a photo (my bits are currently detached from the fuel tank which in turn is detached from the car!).

The relevant Spares Handbook page can be found here:
Resources - Bristol Cars - Owners and Enthusiasts Forum

George

[Kevin H]

Welcome Mark.

As George has said the send unit is in the top of the fuel tank, which is behind the rear seat.

On my 411 I don't believe it was possible to remove the rear parcel shelf without first removing the seat squab. However my 411 is an S5 with the integral head rests. If I remember correctly the seat squab effectively holds the rear parcel shelf in place.

If your 411 does not have the integral head rests then you may be able to remove the parcel shelf without removing the rear seat - I'm not sure.

If you do need to remove the rear seat, first remove the seat base. This just lifts up from the front - it's a very snug fit so it may take a bit of effort to lift it up initially.

This gives you access to two metal tabs with screws below the squab. Remove these and then move the squab upwards in-line with it's initial position. There are two hooks that the squab locates on so you have to lift the squab off these before you can pull it out.

You should find horse hair insulation and a steel bulkhead behind the squab which covers the fuel tank, however you probably don't need to remove this to access the top of the tank - I think you just need to remove the rear parcel shelf. Sorry about the vagueness, but it's probably 10 years since I had mine apart and I can't find my photos.

If you need or want to remove the rear bulkhead it is held in place by approx eight small screws hiding beneath the insulation.

[Sterly]

George & Kevin, that's a great help. Many thanks.

[stovo]

Not sure how much help these will be - they're what I have of the top of the 410 tank after it was taken out to trace a persistent fuel smell in the cabin.
As you can see from the paint finish distress in the photo, fuel was seeping out of the seal at the top of the tank around the sender.

The design hasn't changed much from the early days - the 405 is very similar and Kevin's description of the removal process was almost exactly the process I followed on the 405 to get at the dodgy perforated pipes that were causing fuel starvation. Runs much better now the mixing of fuel with air is the exclusive preserve of the carburetors.

Good luck!