Fuel Sending Unit
 

My gas gage reads 1/4 when the tank is full and when the tank is cough-sputter-dead-empty [ learned that last thing the hard way:o ]. My machine was in storage from 1981 until last December and off hand, it looks like the float is stuck. Replacing the sending unit is not on my list of fun things to do -- busting loose a lock ring that has been in place for 23 years opens up scads of chances for a static spark and fireworks like the fourth of July. Does anyone have any good ideas on replacing a sending unit without tearing up other stuff or doing something worse? In the meantime, a two-gallon gas can will be my reserve supply.

I feel for you. I am putting a new fuel tank in my '82 F-250. I thought it would come with a sending unit like the marine tanks do. I found out the hard way. I went to the local Ford stealership for the part and was told $123.00 and change plus the tax. I asked him if there was a special tool to remove the old sending unit, he said "No, just get a screwdriver and whack away at it!" I told him he was insane and left. I got the old unit out while praying to the almighty that I did not blow up because of any sparks. Much to my chagrin, I have to replace it since it was all varnished up and rusted and rotting. I am getting my unit from LMC Truck (cheapest).

Get a new fuel tank and sending unit. Replace all rubber hoses and use new tank straps. I think that is the safest way. Unfortunately it is the most expensive way.

I was told from someone that using gas line antifreeze for the next while on fill ups helps to clean the gumming that causes poor gas readings.
The gumming causes the floats to stick and the sending unit also sends wrong message of how much gas you have.
My trucks gauges move too much when I drive. So I'm trying this method first before trying to have to take the sending unit out.
Gas line antifreeze is methonol hydrate and it does not take much on a fill. Just a few onces. So you could try this and see if it loosens things up. If you have rust, I would change the fuel filter down th line.
There is a tool for taking the sending units off, but are a special order and one size does not fit all. Have removed lots of units the way you say. Tap the ring off with hammer and chisel. You do not have to hit hard, just tapping breaks dirt loose and blow away after a couple of taps. Then you do not have the grit making it hard to remove the unit.

Thanx guys. The gas line antifreeze has been suggested and that seems to be the easiest, next step to take, probably the least expensive too. Two tanks of gas should tell whether or not things are loosening up. ...will keep you posted.

The gas line antifreeze has worked to free the float and now the gage will show almost full when the tank is full. The other problem is still with me: brown crud in the fuel filter and a stalled engine when the filter gets clogged. The crud will probably be there until the tank gets a good clean up. The saga continues.

Had a similar problem on my 78. It had been sitting being used for a few years when I bought it. The one tank got the crude which is the gummy deposits from the old gas. It took a cou[le of filters til it cleared up. At least an inline fuel filter took most of the crude, but still had to change on the carb 2 times. Good luck

I had the exact same problem as you Jim. Same symptoms learned the hard way as well!
After 23 years I would replace the fuel tank and sending unit. There is also no real elegant or (perhaps) safe way of removing that ring. The reason why your filter gets plugged is that there's probably so much rust and dirt from your tank being so old and setting for such as long time. I had to replace the sending unit and then it worked fine. As well check for any shorts, this can make the level read way off when it shouldn't.

The crud still continues, stopping up a fuel filter and shutting down the engine. My local friendly mechanic gave me the words of wisdom about using two filters which thankfully has saved other headaches.

I have been looking for a gas tank, the tank/filler neck seal, a vent seal, and a sending unit. JC Whitney has a tank for about $160 and Dearborn Classics shows a "...fuel filler rubberseal..." which sounds like it is the right piece. I can live without a new sending unit for the time being; the gas line antifreeze seems to have got it loose but its definately wrong [shows "E" but can't pump but 12 gallons]. Does anyone has a suggestion about the vent seal: what is looks like, could it be made with average skill, or where to find/buy, I would greatly appreciate any help.

Try LMC trucks, they have stuff cheap. 1-800-LMC-truck or www.LMCTRUCK.com they also have a toll free 24 hour fax at 1-800-541-8525.

Had same problem
 

Have a '66 Falcon Van that had the same problem .... dropped the tank and drained it ... shone a flashlight in the gas filler opening and saw nothing but crap inside ... had a reputable professional reline the tank ... ordered a new sender from Northwest Falcon in Portland ... save the old lock down as the new Taiwanese ones do not work ... do not allow the breather on top of the tank to get pinched or twisted ... further to this, the inside diameter of the pipe is a common size ... but the outside is not ... if you try to replace the rubber up into the gas vent tube through your existing framework, you will realise that it will not go in the stock hole ... what I did was take a true fitting hose to just past the gas tank near the upturn into the framework ... then I reduced the size of the hose by 1/8" with a fitting and ring clamps to accomodate the new hose up into the framework ... it was the only way I could think of besides using the piece of garden hose that was there ... If this hose is pinched, twisted or otherwise, your crate will stall out whenever it feels like ... also replace the fuel line ... if your sender unit and tank looked like mine, do the full Monty ... buy a section and a flaring tool and do it right from front to back ... as far as I'm concerned go all the way and eliminate the possibility.. it makes future diagnosis of problems simply a process of elimination ... if you are covered in fuel ... underside crap etc ... go all the way ... It'll save you tons of aggro. in the future ....