Packard Forum Index » V-8 (1955-56)

Recently installed a fuel sending unit from a well known Packard parts guy.
Went to a show and on the way home gas gauge read half a tank but it really was empty. Is there a specific way to install the sending unit in the tank? Is it possibly the gauge or sending unit. Need help with this guys.

The float goes rearwards.

I would say the unit broke the ground strap. Inside gauge.


Sending units. Ford. 10-70 ohms.

My blog shows it

As I recall sender position doesn't really matter much but if there is clearance and no locating notch on the tank then if mounted so the float goes toward the side of the tank that tends to minimize the gauge changing if the float wants to move up and down as gas sloshes when doing ordinary stop and go driving. The 51-6 gauges are bimetal heater type so do not move very fast. Unlike the earlier magnetic gauges, later gauge changing is probably a non issue.

Unless you have an opening cut in the trunk floor to easily remove the sender it is a bit late and hard to check for proper sender operation. If you do drop the tank and remove the sender, using an ohmmeter connected between the terminal and the sender mounting flange you should read approximately 70-75 ohms at the empty end and 10 ohms at the full end.

The instrument voltage regulator works the temp, oil, and fuel gauges. If none of the other gauges are having problems it should be OK. To test the fuel gauge will require the use of a known good sender. From 1951 on all the gauges use senders with the same electrical specs and work the same way so that testing procedure is detailed on page 55 in the 1951 service counselor Vol 24 #12 Just grounding the sender wire will do a rudimentary test in that as soon as the wire from the sender touches ground the gauge will start to rise to the full end. Do not leave the wire grounded any longer than it takes to verify the gauge needle reaches full.

One other consideration is that a pinhole in the fuel pickup line inside the tank can mimic an empty tank. If the tank was actually empty and took about 20 gallons to fill then the sender or gauge is an issue but if it only took around 10 gallons there is a possibility of a pinhole and the pump started sucking air.

The two places pinholes have been known to occur are noted in this photo Ross provided showing the tank inside.

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  51-6 inside pinhole locations copy.jpg (131.28 KB)

OK. I finally decided to replace the tank.
Too many issues as it may be the pickup having pin wholes in it. Seems when i drive up inclines car misses and wants to stall.

So does anyone recommend where to purchase one as I see them on Ebay. Please any help would be greatly appreciated!! I love the car and would like to get 100% without worry of driving it. Thanks again for all your support and for responding.

I got mine from Kanter and installed with no issues. Works well. It is about a couple week lead time until it arrives at your door.

if your worried about the gas gauge reading right. One thing you can do is install the sending unit in the tank, attach the sending unit wire to the sending unit and run a jumper wire from a good ground on the tank to the body. turn the key on and note where the gas gauge is sitting, that is when the tank is physically empty. Turn the tank over and wait a minute or two. that will be your gauge reading once the tank is fuel. If you dont like where either is at you can bend your float arm to adjust the full and empty points on the gauge.

Last I heard Kanter had sold out of the new tanks but Auto City Classic still had them. They may be the same company who is selling the tanks on ebay.

So Kanter does not have them anymore. Ordered one from Auto City Classics.
Hopefully this will solve my issue.
Thanks to all of you for the help.

Installed new tank from Auto City Classics now problem fixed. Thanks Guys!!

A new tank fixed the vexing fuel issues on my 55 400. So much crud in the fuel that couldn't get flushed out. Fuel sending unit also was an issue.....float was missing LOL....
Everything working properly finally.