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I’ve seen several threads about the gas gauge erroneously reporting half full, when the tank goes empty. Frequently the problem is a clogged canister, causing the fuel sending unit in the gas tank to be partially crushed and preventing the float from falling below half full. The solution frequently given, besides a canisterectomy, is to remove the tupperware, pull out the sending unit, and correct the crushed sending unit by drilling a hole in the cylinder that makes up the sending unit, and pulling the bend out.

The purpose of this post is to describe how to take the fuel sender apart, rather than drilling the hole, to correct the crushed area. This description is based on my ’99 fuel sender.

At the bottom of the metal fuel sender cylinder is a heavy spring. Remove this spring from the several prongs that hold it by prying with a screwdriver, starting about 1 revolution of the spring away from the end of the spring. (I did not have to bend the prongs, and would not suggest doing so.) This then allows access to a 5mm nut, which is held from turning by a washer, which has been bent up onto the sides of the nut. Bend that washer flat to allow the nut to turn, and remove the nut. Now the bottom cap of the sender can be removed. I marked the bottom cap with a pencil line, so I could reinstall it in its original orientation. The metal tube can now be slipped down and off of the innards of the sender. Obviously, do this carefully.

The innards of the sender consist of a long pair of wires running the length of the unit; for mechanical support, a long, thin rod, ending in the threads that held the nut you just took off; and a float that rides on these wires and rod. Now the unit is apart, and the long cylinder culprit with the crushed center is in your hands. I used a cylindrical piece of wood (the end of a snow shovel) to press inside and reform the cylinder.

Reassembly is as you’d expect. I found I could reattach the spring by starting at the end, and working one prong at a time, starting with the outer prong of a pair of prongs, and then the inner prong of the pair.
 

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Thanks!

Thanks much for this info, DonR!. I too have a '99, have not done the cannisterectomy (although I think now that I finally will), so it's great to learn this about fixing the fuel sender unit.
 

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I just finished repairing my fuel sender, in my case I believe, due to the previous owner inserting the gas nozzle towards the sender housing and denting it. There were many dents with scratch marks that wouldn't lead me to believe they were the result of the tank crushing it.
I don't think a few of the steps above are really necessary. I didn't remove the spring. Thought it too destructive and used a pair of needle nose pliers to remove the small nut and bent washer through the end of the spring.
I also used a carpenters square (ruler) to remove the dents. The more narrow end of the metal square was a perfect fit for the I.D. of the tube. Hope yours is the same, but I didn't want to press out the dents with something that was likely to leave the tube with a lot of small dimples. The square, being a perfect fit, made it easy to just rotate the tube on the square, that was held by a vise. Initially, the tube doesn't want to rotate past the dents, but little by little the heavy metal of the square won out over the easily dentable tube and I have an almost perfectly round tube again.

Hope that helps,
Jer
 

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