504 Fuel Gauge
- Thread starter Glenn
- Start date
I don't know what voltage you should expect, but I do know that if you take out the sender you will most likely see wires wound around a flat piece of bakelite, and an arm which travels across them. Those windings tend to bunch up due to the arm pushing them.
Apart from getting a new one, I've never been sure how to fix this. The arm only just touches the windings, so you don't want to stuff around with it all too much. But I did once entertain the thought of pushing them all back where they should be and trhen super gluing them in place.
Or getting the same kind of card from another car and hoping the resistance is the same.
Apart from getting a new one, I've never been sure how to fix this. The arm only just touches the windings, so you don't want to stuff around with it all too much. But I did once entertain the thought of pushing them all back where they should be and trhen super gluing them in place.
Or getting the same kind of card from another car and hoping the resistance is the same.
If you get a 504 fuel gauge to be accurate it will be a first and a Nobel prize may come your way!
Pics below of a new old stock sender that I have if they are of any use. '12V' is noted on the white plastic section.
Upon inspection they don't look to be very solid or 'rebuildable' at all. As described by Beano above the arm only just touches the winding or metal strip and the whole thing is very delicate.
I had a fluctuating gauge in the past and an auto electrician just popped the dash top off and added an earth direct from the back of the gauge to part of the chassis metal nearby and it fixed the issue. Id try that first. Sounds like you have voltage at the rear of the car so it may be at the gauge area.
This gauge is for an 'Early' car as per the sticker and Im not sure if they changed later on or when.
Upon inspection they don't look to be very solid or 'rebuildable' at all. As described by Beano above the arm only just touches the winding or metal strip and the whole thing is very delicate.
I had a fluctuating gauge in the past and an auto electrician just popped the dash top off and added an earth direct from the back of the gauge to part of the chassis metal nearby and it fixed the issue. Id try that first. Sounds like you have voltage at the rear of the car so it may be at the gauge area.
This gauge is for an 'Early' car as per the sticker and Im not sure if they changed later on or when.
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My 504 cab had an extra earth wire fitted from the instrument panel when I bought it .Maybe it was for this .The gauge never shows completely full or empty but goes from three quarters to one quarter and I use the trip meter to know when its time to fill up.
the electricals inside the sender is just like a variable resistor, due to years of movement the coil winding would have had massive wear and carbon built up, so first bet is to replace the sender, second ensure your ground is good. I would always reground various section of my car back to the battery negative points. lots of improvements especially for the electrically related parts.
With the wire unplug, the supply to my 404 sender is something like 10.5 volts.
With the wire unplug, the supply to my 404 sender is something like 10.5 volts.
Adding to my previous post ,I know it reads three quarters when full but I don't know what it reads when empty because I never let it get anywhere near empty .All I know is the gauge goes down as fuel is used.
Sorry Andy,
sold them as a job lot years ago.
Ian.
sold them as a job lot years ago.
Ian.
My 504 gauge was always dead accurate, (about 40 years) until the 504 became a sit around back of the garage car ( 10 or 12 years ago). I am sure the sliding pickup contact corrodes up, now each time I take the car out (on average once a year for rego check) the gauge flicks around and carries on. By the time I arrive back home about an hour of driving, it is back to working problem free. Something in the fuel that corrodes them up if the car stands around?
Adding an earth was exactly what i did to a 604 and it was actually accurate, possible the only accurate 604 fuel gauge ever !!!
I thought 604's all ran around near empty? 
thats right, gauge cant be wrong thenI thought 604's all ran around near empty?