Gas tank sending unit replacement

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MustangSally44

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Hi guys...My wifes gas guage hasnt worked since she bought the car.. I read the sending units go bad and is probably the culprit. Picked up a new sending unit at a swap meet and was thinking about installing it myself. Of coarse theres no instructions so is there anything I should be aware of before tackleing this. Trying not to learn the hard way.. Thanks.
 
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1971 Mustang Mach 1 M code 351 4 speed
I replaced my sending unit and fuel tank about 6 months ago, it is a pretty straightforward install. There are a couple of thing that I would do when replacing it. Change the rubber fuel line that goes to the sender, mine was really bad, so have some additional fuel line. The other thing that I would do, is make sure that the float is where it should be, by that I mean that after I installed my tank and sender, when the tank if full I only show 3/4 of a tank of fuel. This is easily adjusted when you have the sender out by just bending the steel rod that holds it so that when the tank if full you show full on the gauge. Of course I did not check this and well, I am not taking this out again just to bend the float rod. So check it while it is out of the car to make sure that when the float is at the top of the tank, you gauge reads full. You will need to kind of do a mock up on the outside of the tank and eyeball it, but it should be quite easy to do.
 
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Here's what I found when I replaced my tank a couple of year ago (or was it 3!)
First, make sure your sender is the correct one. I bought my tank, Spectra Premium F32A (Canadian made) from RockAuto as it was cheaper than buying it locally believe it or not. I also bought the Spectra sending unit, FG87A, but found there had been a mistake in their numbering and it was the wrong one. I reordered a Dormann 692232 which is a very good replacement unit.
To install, I did have an empty tank, so I bought 19 liters, 5 US gallons, of premium gas. That should have the gauge read 1/4 full. Afterall, it's the bottom 1/4 that's most important! I don't remember now if it was high or low, but regardless, what I did was to use TWO floor jacks to raise the left side of the car (one at the front jack point, one at the rear) AND used jack stands, high enough to be able to remove the sender without spilling gas. Adjust the arm as 71ProjectJunk describes until it read 1/4 full. It's a bit of a pita, but worth doing right.
As for your lines I suggest using fuel injector rubber hose as it is ethanol resistant on the INSIDE and PLEASE< use proper fuel line clamps, either spring type or the ones I show at the pump. NEVER use gear clamps on fuel lines (or anywhere else that really matters).
 

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MustangSally44

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You guys are the best. Thankyou for your feedback. Had a good look at the tank and it's got several years of undercoating over the sending unit. Probably original. Was wondering if I should trust the new rubber gasket on an old tank or is there something I should be sealing it with. I was thinking butal rubber but I'm sure you guys might know a better product if it's even needed. Thanks
 
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1971 Mustang Sportroof M code
All you need is the new rubber seal that comes with the sending unit, you do not need any additional sealant in there. I have done a few of these, and I have yet to see one leak.
+1, anything else added to it will likely peel off and wind up in the carburetor.
 
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Bobby

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I replaced all my gauges on my 72. The fuel gauge presented a unique problem. Two years ago I replaced the gas tank and sending unit. The old tank was nasty and the sending unit didn’t read past 1/8 tank. Last summer I replaced all my gauges. The oil pressure, temp and voltage gauges were replaced with equus. The speedo, tach and fuel gauge with Autometer. The fuel gauge read full and empty without any issues but everything in between was crazy off. I called Autometer and they told me that the aftermarket sending unit was not compatible. I had two choices. One was to send the gauge back to Autometer and for $25 they would reconfigure the gauge and utilize a different face with different graduations. The new face was going to be radically different in appearance. Two, I would have to find an OEM sending unit as the gauge was calibrated only for OEM senders. I found a new old stock one on eBay but I won’t tell you how much I paid for it. The only problem I had was getting the o ring gasket to seat properly. It took two attempts but with a little permatex I got it seated properly and all is good. I wish I new about these rebuilt OEM units!
 
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1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
I replaced my original with a reproduction. First year of driving one of the contact pins fell off.

I put my original back in.
Kcmash
 

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