I plan on installing a new fuel sending unit in my 1972 240z tomorrow.

Do I have to drop the fual tank to perform this installation or can it be done with the tank still in the car?

On my 71 it was on the front side of the tank. I installed mine with the tank out of the car, but it might be possible with the tank installed. Check for sufficient clearance first. I guess that if you try to do it in place and can't you could always drop the tank if needed.

You will have to drain the tank first. (But you knew that I assume.) On the early cars the sending unit goes on the side of the tank near the bottom.

Also, do your self a favor and carefully check the old float arm angle and bend your new arm to match. I just installed the new unit with the arm straight, and as a result the gauge registers 7/8 full with gas filled up to to the cap on the filler neck. When I hit empty on the gauge the tank still has about 5 gallons (U.S., about 19L) left in place. It is very annoying, but not so much that I am willing to take the sending unit back out to fix it.

Oh my gosh Walter I have the exact same issue! I installed a new one and did not even think I had to bend anyhting, but low and behold, I never get over 3/4 full, and I go from 3/4 full to 1/4 full in about 30 miles. Very annoying. After 10 fill ups I have figured out just how far I can go. But I still want to fix this issue one day.

Hah, so I'm not the only one with that same exact issue.

"I know it says empty! Just freakin' trust me okay?"

When I put a new one in, I did a side by side comparison to see if the angle was equal, it was. The tank was out of the car so I installed the old one and looked through the filler opening to see the float bottom about 3/4 inch off the floor of the tank. Installed the new one and the float was in the same position, so I did not bend anything.

A NEW O-ring is a must to prevent a leak.

Bonzi Lon

I have the same challenge as well - has anybody figured out how far to bend and to what extent?

This may help somebody if theirs just needs cleaning and refreshing:

http://desertdatsuns.freeforums.org/fuel-tank-sending-unit-t206.html

http://www.classiczcars.com/forums/help-me/38577-another-fuel-gauge-problem-please-help.html

Edited March 24, 201312 yr by Travel'n Man

I did not bend mine and it works perfect.

Dltalfa.... I installed one in my green Z while the tank was in the car. Remove the two wires from the sending unit, with a short flat head screw driver, tap off the lock ring.......remove the old unit. Coat the (new O ring with grease)so it stays put while you slide in the new unit, then tap on the new lock ring....reattach the wires. One hour job....no problem.

Edited March 25, 201312 yr by Diseazd

I did the same as Guy, but I used vaseline to hold the O-ring in place. Just make sure your fuel level is low enough before you start so you don't dump fuel on the ground. Even jacking up the front end would help for this.

FYI,...I replaced my fuel sending unit and did NOT have to remove or lower the gas tank. I just put a jack under the tank for support,...I removed the rear wheel,.....removed one tank strap, (to provide better access),..and then just replaced the unit.

It was so simple,...took less than an hour total.