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Sending unit replacement

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RomanH

RomanH

Jedi Knight
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I have determined that I have a bad fuel tank sending unit in my 6. Is it possible to replace the unit without having to remove the fuel tank entirely? What I was thinking of doing is to run the fuel down by having some fun with the car /ubbthreads/images/graemlins/grin.gif and then unbolting the tank, removing the filler tube and only tilting it to access the sending unit. Has anyone done it this way or will I just end up breaking the fuel pipe exiting the bottom?
Thanks
Roman
 
This will probably be ok if the fuel hose is in good condition where it connects to the main line......but it would be beter to just take it out, clean it, and freshen up the hoses too while you are at it. It will violate the" do it once,do it right" rule of thumb.......which we all have regretted latter.
MD(mad dog)
 
Here's my story:

I thought I'd finesse it by getting the sending unit out of my TR4, without removing the tank. I couldn't. There was no room to do it without stripping the top sealing screws and rifling the tank around in a manner that I would not be comfortable with. Further, I don't feel I could have done a good job on the top gasket with so little room to maneuver.

What I want to tell you, however, is how happy I am that I did not try to cut corners and leave the tank in.

And, by the way, don't try to run the car empty. That never seems like a satisfying allocation of time and effort. Get a $6 siphon bulb from Checker (DO NOT TRY TO USE A FLUID EXTRACTOR PUMP), and also get a nice new steel five gallon gas tank. Good tanks are handy anyway.

Just drain the gas out in ten minutes. You'll feel better knowing that two gallons won't come running out onto your garage floor because you didn't drive far enough.

When I removed the tank, I noticed rust and thin spots on my tank, including two pin hole leaks that I never would have discovered until much later. Further, I refurbished my entire tank area, sanded out the old rust, installed new heat and soundproofing material, repainted the area, and sealed it. I also replaced the top filler hose and clamps--which also showed fatigue and leaks.

I put a new tank in the car and feel much "safer" and smarter. I kept the old tank in case, out of nostalgia, I decide to have it "restored" as I hear can be done.

But, then, it got tedious. By examining the gas line where it enters the tank from the underside, I was able to see a "wear point" caused by constant friction with the frame of the car over 39 years. With my thumbnail I was able to gash an entire three inches of the line, and gas spilled out all over me (there's always a pint somewhere) until I clamped it off.

I then bought twelve feet of new gas line and a quality pipe bender, and spent the next two weekends completely replacing the gas line.

It's done. It's safe. I feel good about going the whole nine yards.

Anyway, I have no idea the condition or details of your tank, but it might be worth taking it out for the experience of it all--and so you can snoop around.

Who knows, you might discover why after driving your TR people seem to claim they smell gas or ask if you were repairing a lawn mover. Good luck.
 
I don't have a dirty tank some PO along the way replaced it (looks brand new) right now it's full and thats why I thought I might want to try it this way.
 
For TR3 fans: the sender on those can be replaced w/o removing or moving the tank (just need an offset screwdriver).
 
Ain't gonna happen, Roman. Ya gotta remove the tank. The sending unit is a bit unwieldy and fragile and requires total access to the top of the tank. If I were you, I would lift the car up high on stands and with the tank almost empty, just cut the rubber elbow that should be in there making up part of your fuel line. Just empty this bit of fuel into a clean container. Taking the filler cap off and wiggling the top piece of rubber off the tank is a trick in itself.
A problem with replacing the fuel sending unit is these are all aftermarket and not made very well. You will never know if the float is set at the right angle until you reinstall everthing. Mine is off a bit and now I compensate with a guess as to how low my fuel is.
Bill
 
Thanks Bill,
I was afraid of that, I just needed to know if it could be avoided somehow. I guess that this job is going to the top of my spring chores list. I hope we have some more nice weather up here so that I can drive the car to use up some of the fuel thats in it now so I don't have too much to drain! /ubbthreads/images/graemlins/frown.gif
 
Not to add to your worries or question your methods... but are you sure it is the sending unit and not the gauge that is at fault? Probably wishful thinking on my part but that gauge would be much easier to deal with (but not cheaper).
 
In my case it was the sending unit, totally fuel-logged float. OE floats were not available, just total replacement after-market units.

Bill
 
Hi George,
I removed the fuel gauge and checked it out as soon as this problem reared it's ugly head and it functions correctly. I next checked the voltage stabilizer and found it to be fine. I then checked the wiring between the sending unit and the gauge by grounding the green and black wire with the ignition on and the fuel gauge moved to full. All that was left is the sending unit, so I measured the resistance across it and found it to be infinity indicating an open circuit. Unless I've missed something I guess I will be changing it out in the near future. /ubbthreads/images/graemlins/frown.gif
 
Very thorough. Didn't mean to doubt you -- just hate the thought of pulling a sound tank unless double-darn sure that's it.

Meanwhile -- I used to use an old yardstick as a gas tank dipstick on the TR3... 1" = about 1 gal.
 
Hi George,
I know you didn't mean anything by it. It's a good thing to double check procedures. I started with everything else first since I had more access to those bits and didn't want to remove any interior panels unless absolutely necessary!
I will use your tip and get another yardstick to use for a gas gauge! /ubbthreads/images/graemlins/grin.gif
Thanks
Roman
 
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