Fuel Tank Relocation for one with no skills!

[Solego]

I have read all the threads that I could find on relocating the gas tank to under the bed using a Blazer tank. They have been very insightful, but for someone as myself with few mechanical skills, I have many a question.

1. What is a "sending Unit?

2. Where exactly does it go?

3. What does it do?

4. When others have stated that you must notch a crossmember, wich crossmember are others referring to and how does one notch it?

5. I know what a vent tube does, but apparently something must be done with it in this application, otherwise it would not be mentioned. What exactly must be done with it to complete this installation?

6. Are there any other questions I should be asking?

Thank you guys for being so patient with me in the past. Any and all help you guys can give I am very thankful for!

[Big White GMC]

I Was Kinda Wondering How To Do That Myself. A Sending Unit Relays The Amount Of Gas In The Tank To The Gas Gauge In The Cab.It Is Mounted In The Gas Tank. That's All I've Got. Maybe Someone More Enlightened Could Help.

[Lated]

The sending unit has the fuel pickup as well as a float attached to a potentiometer that relays the fuel level to the fuel gauge.

[matthufham]

on my 72 longbed fleetside with a steel bed floor i had to notch the bed crossmember so the tank wouldnt touch it. and i removed the spare tire crossmember on the frame which is a weak piece held on by 2 rivets.

in the pic you can see the notch in the crossmember

the sending unit does 2 things

1. it reaches the bottom of the tank and the fuel line that runs to the engine from the gas tank connects to the sending unit. it has a screen on it so it doesn't pick up trash from the gas tank.

2. it holds the float on an arm, and when the float is all the way up it tells your fuel gauge you're full and when the float is all the way at the bottom of the tank it tells your guage you're empty. and of course everywhere in between.

[Ironhorse]

I did the under the bed tank mount on my '71 4x4 and consider it to be one of the best truck mods going. I also notched my truck cross member almost exactly as matthufham did. Looks as if he also is using the poly tank. I did mine with the bed off as the truck was being painted. Here is a couple pics I have of the fuel filler set-up. Lots of options but I decided this would work for me. Good luck with your tank swap.

[Solego]

Thanx guys. I'm assuming a cutoff wheel would do the trick for the notching?

Also, how does the sending unit attach to the new tank? Does it bolt in or does it require welding?

[Solego]

Does the tank ever get in the way of the diff when if and when you change gear fluid or the gears themselves?

[matthufham]

i did the exact same fuel filler as iron horse lol. we're too similar

i used a cut off wheel for the notching because that's the only tool i had that would fit in that tight of an area.

the sending unit has a rubber ring, then the sending unit, then a top metal ring, which is held down with 3 screws on my gas tank.

my truck is lowered 5 inches in the rear and feels like 6-7 with a full tank of gas, and changing rear end fluid is still the same challenge. the hardest part is jacking up the truck when it's as low as mine. the gas tank isn't in the way.

[OLDIRON69]

Same as stated above, I cut my spare tire crossmember out with the trusty sawzall. I notched my bed x-member to clear the sender. I used a tank from a 73-8?? Blazer so my install was a little different. It tucked right up under the bed. I used roll bar padding on my x-members where the tank would rest. I cut the factory neck off my tank and installed a neck from another car so I can fill from the bed floor. This is where the options are endless...
I have not vented my tank yet, I'm still looking for a way to do that with out using a charcoal cannister. I was unable to find a vented cap to fit the neck I used so that is still on the "to do" list. Going with a "kit" maybe your best bet so you don't have to fabricate as much as I did. I made my straps from mobile home tie down straps (Lowes, $10 bucks for enoughto do 3-4 trucks)
Ask away at the questions.....