86 f150 Sending units

[Pebcak]

Ok, I've come to the conclusion that my rear sending unit is starting to have issues.  For the last 3-4 months I thought I had another resistor or dash issue that the fuel levels weren't displaying.

Tonight I filled up and my rear tank is now working.  I think it's sticking or about to go out for good.

The front tank has never displayed fuel levels.

My next project I'm going to tackle is changing out the sending units for both tanks.  Through searching the interweb and people I've known in the past I've seen sending units changed two ways.

1. Dropping the tanks

2. Taking the truck bed off and having access that way.

With all of the knowledge here I'm wanting to see what the best option would be.

Should I take the tanks off, clean them out and change the units?

Or just do a swap from the top?

I'm open to any ideas, suggestions, possible fixes or upgrades I can do in the process.

No emergency to do this because I know I get about 200 mpg on the front tank and 180 mpg via the rear.  

Thanks for reading the way I type.  I type as my mind thinks.

[Gary Lewis]

I think it would be a real dog's-breakfast if you didn't type the way your mind thinks.  

I've done it by lowering the tank on the all-thread that retains it, sitting under the truck, tapping the lock ring back, and extracting the sender.  Worked a treat.

As for dropping and cleaning them, I wouldn't if they aren't giving you trouble.  For the price of a new tank it just isn't worth it.  I did it once, spending several hours and several gallons of gas in the process, and still had silt plugging up the filter for a while.  But if you aren't having silt problems, I'd leave well-enough alone.

[grumpin]

I just had my rear fuel pump replaced. Quite the fiasco. The lock ring was stuck on the tank, rusty they said.

They ordered a new tank and new sending unit, the sending unit wasn't correct. I gave them a Spectra part number I thought would work, they could tell by looking at it that it wouldn't.

They got the lock ring off and used the old sending unit (which works better than the front one). I opted to use the new tank, for reasons Gary mentioned.

I don't know what your F150 has in it, but I don't think there are any sending units available for the 19 gallon steel rear tank, at least for the 1986 trucks.

[ScubaSteve]

One thing to check would be the electrical  connection on the top of the tank. My gauge was all over the place and I found a bad connection. You can buy a new connector and terminals at the parts store if needed. As for your question about how to go about getting the sender out I drop my tanks down. If the tank is funky and the sender is bad I would probably replace it all. I think you can buy a complete tank with sender and pump from Rock Auto for not too much $.

[vjsimone]

I’ve been down this route both ways, but if I had the means to lift the bed, and I was going to keep the truck for the long term;

I would lift the bed, remove and clean both tanks, replace sending units.
Inspect all the wiring and connections under the bed.
Clean and re-grease the connectors as well.
Inspect the fuel lines.

But, unless you have some sort of hoist to lift the bed, and able to push the truck out from underneath it’s not an option.

[Steve83]

Making a hoist is really easy & not as expensive as you might think.  This one is metal, but wood will work:



But the bed isn't as heavy as you might think, either.  It can be lifted from below using a common bottle jack on some sturdy cribbing, or just by 4 large guys (on level ground with a stand already set up nearby, or a 5th person to set stands under it).



Read this & the NEXT several captions:

[MotorsportXLT]

If you can find someone with a 2 post lift. My dad and I replaced the fuel pumps in my lightning using the lift. It was nice because the bolts dropped right back in

[Pebcak]

Thank You all for the information and suggestions!  Crazy week and didn't get online like I wanted.

"If" I can find someone with the two post lift I may try that.

With that not likely, I'll probably end up lowering everything as most people say.  But, I will be looking at RockAuto and seeing how much a whole setup might be too.  And the fact that I'll probably be going back to the Pick N Pulls again before it gets too bad.

I can live with it for a bit since I've got my MPT "Miles Per Tank" down pretty good.

[gtanns]

Sending unit question -- Mine doesn't work and I'm now getting custom fab dual tanks installed (approx 150L) but they will be mid mounted similar to the OEM mid mount, but on both sides of driveshaft, and connected at the bottom front (fuel) and top back (air). I'm using original gauges.
Looking at sending units, some say they were for aft tanks, some for the mid tanks....

As long as I stay on the 10/75 ohms, does anything else matter, or would the 'rear tank' sending unit be just as good as any other one for my application?

[Gary Lewis]

I've not seen anything different or better between the rear vs mid-ship sender, so don't think it matters.  But if you are buying you might get one for the 33 gallon Bronco tank as it has a longer float arm, which may be required in your application.

However, what you probably will want to do is to put the sender in and peer in via the filler hole and get the float to be at the top of the range when at the top of the tank, and vice versa.  That may require bending the arm and/or changing the length thereof.