Fuel Tank Float Unit

Martin9645 · #1 (**permalink**) 09-07-24, 02:07 PM

As a NEW Bristol owner I am trying to locate some parts for my fantastic 1970 - 411 Mark 1.
I have a fuel gauge not working which I think will be a faulty Float Unit.
1. Would you agree with the most likely dignosis?
2. Where can I find a replacement unit if required, I believe the part No to be 907-1-33010 (Smiths FT.5301/17

Giles · #2 (**permalink**) 09-07-24, 02:17 PM

Holden sell sender units - you would need to adjust the sender for length. Could be the gauge as well of course - you could test if the sender is working by seeing if the voltage to the gauge works when you fill up.

Nick Challacombe · #3 (**permalink**) 09-07-24, 02:51 PM

After 25 years of ownership of my Bristol I have got used to what Briam Marelli called a std fuel gauge reading. When I fill up it says full and stays there until half a tank has been consumed and then drops to half. It works well after that. I have a spare tank and fuel sender which I bought about 20 years ago, as one does, just in case, but rather like Alfa Romeos I have got very used to my Bristol's quirks.
I recommend Holdens as well, they understand what you want or need.

DODD · #4 (**permalink**) 09-07-24, 04:43 PM

Martin,
Contact Graeme Payne at Classic Bristol Car Parts, I am sure he will be able to help. I bought one from him a few months ago.
Brian

Roger Morrall · #5 (**permalink**) 10-07-24, 04:56 AM

You don’t describe the symptoms.

Be aware that there were two sorts of fuel gauge- The posh sort, as used by Bristols, which shows the fuel level as soon as you switch the ignition on and the basic sort, as used on eg Morris Minors, where the gauge takes a time to react.

The posh sort will immediately show Full, indeed over Full, if the tank unit has gone open circuit whilst the basic type will show Empty.

So if yours shows full all the time it could be the tank unit or the connection between the gauge or the tank. If it shows empty all the time I’d suspect the connections to the gauge as while the gauge itself is very clever it’s also extremely robust. By the way the gauge has to have both earth and power connections so if it appears to be the problem check both

Martin9645 · #6 (**permalink**) 10-07-24, 08:26 AM

Thank you for all your advice.

To Roger, the fuel gauge does not move. car has been in a collection for 12 years so don't know how much it has been driven in that time.

I am going to check the sender unit first, if working will check all wiring to the gauge. may be lucky and its a broken wire (have had a couple of those)