• Welcome to For E Bodies Only !

    We are a community of Plymouth Cuda and Dodge Challenger owners. Join now! Its Free!

Gas tank swap ‘72

Pupi_13

Member
Joined
Aug 29, 2020
Messages
7
Reaction score
0
Location
PA
Need help changing a gas tank and float. Any play by plays?

‘72 Challenger
 

340challconvert

Well-Known Member
Joined
Feb 13, 2011
Messages
5,177
Reaction score
2,707
Location
Parsippany, NJ
I picked up a zinc tank vs the steel tank. Should offer better corrosion protection. My car is an early 70; your tank will have the 4 vent lines. Drain the tank of gas first (very heavy and dangerous if you do not) The tank is held in by two straps with long bolts at the back of the tank. Easier to remove if you remove the rear valance (a little more difficult with the pan in) I loosened the bolts after draining the tank, only partially at first. There are screws that hold in the filler tube that need to be removed. The rear vent line hoses should be removed from the tank. The tank sending unit should also be removed (has a circle lock ring that has to be removed (I used a screw driver and hammer to GENTLY unlock the sending unit) Remove the sending unit and be careful with the ground strap that is attached to the outside of the sending unit base. Bad ground and the new sending unit will not work. I then slowly dropped the tank and wiggled the filler tube out of the tank (sealed in with a rubber grommet; Make sure you order a new grommet, it may come with the new tank.) I supported dropping the tank with my floor jack and a small piece of plywood on top. Tank should be out at this point. Check the condition of the rubber hoses (vent lines and gas feed line to the tank (replace if needed) Also a good time to blow out the gas feed line with some compressed air or replace if corroded; remove other end of metal fuel line at the fuel pump if you do this) Replacement is the opposite of the previous steps. As mentioned above, I chose to buy the zinc tank. Sending units repro units tend to be iffy. One is being sold with a plastic float (not for me) I found one with the proper copper float, Test the unit before you install it and make sure the ground strap is installed correctly. I also picked up new tank hanging straps. The originals can be reused if they are in good shape.
Hope this helps!
Pic of my original sending unit, gas tank grommet and what the 72 Challenger sending unit looks like after replacement;

IMG_2808.JPG


IMG_4805.jpg


View attachment 75358

72 Challenger gas tank sending unit.jpg
 
Last edited:

340challconvert

Well-Known Member
Joined
Feb 13, 2011
Messages
5,177
Reaction score
2,707
Location
Parsippany, NJ
Some last thoughts; new gas tank pad is also a good step; here is a pick of a 72 Challenger tank and vent lines, Not sure if your car is an early 72 or a late 72. Some early 72's still used the late 71 vent tube set up. Later, a small vapor separator was added to the rear shock cross member. The junction box is the 4 vent lines going in the bottom with a vent tube going out the top and up to the Charcoal Canister in the engine compartment. (pic below)

72 Challenger gas tank and vent lines.jpg


72 Challenger gas tank vent lines 2.jpg


72 Challenger vent junction box.jpg
 
Last edited:

Pupi_13

Member
Joined
Aug 29, 2020
Messages
7
Reaction score
0
Location
PA
Appreciate the response @340! Few questions, that I may understand better once Im working on this issue.
1. Is this a front vent or a side vented tank? Confusing from the installed pics of new tank vs the un installed pics of tank. Looks like your sending unit is in the rear so Im thinking you have a front vented.
2. What is the long steel tube with the 4/5 smaller barb fittings sitting on the the uninstalled tank in 1st pic of 2nd reply?
3. Would it make sense to remove the rear bumper? Could it be done without this bumper removed as I feel we may open a can of worms.

Car is old and know it will need work so I wanted to get it running, a small tune to see what else is needed before we tear it apart this Winter if need be. Gas tank is necessary as it was leaking from the bottom so all fuel is out of it.

Thanks again.
 

Chryco Psycho

Well-Known Member
Joined
Dec 28, 2008
Messages
4,401
Reaction score
2,040
Location
Panama
Filler neck slides in the passenger side , sending unit is on the drivers side , if you have 4 vent lines they come out the front above the differential
 

340challconvert

Well-Known Member
Joined
Feb 13, 2011
Messages
5,177
Reaction score
2,707
Location
Parsippany, NJ
The large tube with the 4 “barbed fittings“ is your fuel filler tube on the passenger quarter to the tank. Your car is a relatively early 71 October build, it might not have the vapor separator on the shock cross member toward the front of the tank. I would get under there to see what you have? You can get at the tank bolts without removing the bumper or valance; though it makes the job a little easier, IMO
As Chrysler said, filler tube on passenger side, sending unit on the driver side. Vents lines are on the right side of the tank.
 
Last edited:
Back
Top