Replace gas tank and sending unit or not?

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72Plymouth

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My gas gauge reads empty, then I fill it until the pump clicks off, and by then it overflows. It only takes about 6 gallons from empty until full. I know that it holds more than that. Maybe there is really half of tank left when the gauge reads as empty. I'm almost certain this is a problem with the sending unit correct? Could the current one be fixed or is a new one the solution?

Also, would you guys recommend replacing the gas tank if I am going to rebuild the engine? I just didn't want any crap that might be in the tank to get into all the new stuff. I know the fuel filter is there but wanted opinions. The original tank looks good other than some light surface rust.
 
My gas gauge reads empty, then I fill it until the pump clicks off, and by then it overflows. It only takes about 6 gallons from empty until full. I know that it holds more than that. Maybe there is really half of tank left when the gauge reads as empty. I'm almost certain this is a problem with the sending unit correct? Could the current one be fixed or is a new one the solution?

Also, would you guys recommend replacing the gas tank if I am going to rebuild the engine? I just didn't want any crap that might be in the tank to get into all the new stuff. I know the fuel filter is there but wanted opinions. The original tank looks good other than some light surface rust.
My 72 Duster had the same issue and I pulled the sending unit and found the sock was deteriated and the float was full of holes which is why my sender wasnt working.I also found alot of rust in the 1 barrel carb float bowl when it had the slant six in it so im planning on either just getting my current tank cleaned or get a new one.SOmetimes you can just get a new float and sock for the sending unit and it will work again,but its much better to just get a new one and not worry about it anymore.:-D
 
Your sending unit probably looks like mine did.With the age of these cars replacement is a good idea IMO.If the tank is clean inside I'd just replace the sending unit.You won't know till you open it up though.My 72 Dart's tank looked absolutely spotless inside,that car had been somebody's dd and probably never sat.Now My 73' which sat in a field for some time was another story the tank couldn't be salvaged.

floor pan repair 002.JPG
 
Whoah yeah it probably looks like that lol. Is there a way to get a look at the inside of the tank without dropping it? Like possibly from the trunk by taking the filler neck off?

Also, the sending unit can be replaced with the tank still in the car correct?
 
Only way to peak inside is to pull the sending unit. Raise the car and put the jackstands under the frame, to let the rear end hang down. Use a brass punch (no sparks) to spin the lock ring off. Use a flashlight to look inside.
 
Thanks. What did you mean about the punch for taking the retainer ring off? We have a 4 point lift, so I could try on there but the rear end won't hang down.
 
The sending unit is held in place with a lock ring around it's perimeter. It has to be driven counter clockwise by hitting the edge that sticks up with a punch. A brass punch will not cause sparks that could lead to an explosion. Not likely, but could happen.

I'm not condoning it, but I've seen them driven off using a large flat blade screwdriver and a hammer.

If you have a four point lift, the rear end WILL hang down, allowing easy access to the tank and sending unit. Much easier than laying on a hard concrete floor!
 
The sending unit is held in place with a lock ring around it's perimeter. It has to be driven counter clockwise by hitting the edge that sticks up with a punch. A brass punch will not cause sparks that could lead to an explosion. Not likely, but could happen.

I'm not condoning it, but I've seen them driven off using a large flat blade screwdriver and a hammer.

If you have a four point lift, the rear end WILL hang down, allowing easy access to the tank and sending unit. Much easier than laying on a hard concrete floor!

Thanks again for the tips. Sorry for the confusion, not four point but I meant four post lift. So the tires are still on the ramps.
 
hi I am looking for a place to buy a gas tank for my 71 dart swinger, the sender does not work, and. there is a dent in the tank just below the sender the local places want around 300dollars can they be found for a chaeper price? thanks
 
There are some on ebay for around $170. Cant really comment on the quality since some brands online might be better. There are some Canadian ones that look decent.
 
I'm not sure if you have already gone and bought your parts, but have you checked to see if your gas gauge is the culprit? It's an easy and free way to make sure you aren't buying a sending unit for no reason.

Pull the little wire off the sending unit and stick another piece of wire inside of the connector and ground it to the chassis. Have someone look at the dash and see if the fuel gauge moves from E to F. If it does then it's your sending unit at fault. If it doesn't move correctly then you might just need a new gauge.

I just pulled an original sending unit out of a 67 Valiant. The sock was completely gone but the brass float and everything looked great. So pull the sending unit if you have to and see what it looks like. You can buy the float and/or sock separately to save money if the rest of it is in good shape.
 
So I run out of gas when the fuel gauge reads 1/4 full. Is this probably the float? or What?
 
i have a 71 dart 318 i just replaced my gas tank and sending unit both new. the gas gauge does not work, i did the wire from sending unit wire to frame the needle on the gauge went from mt to full. i put ten gallons of gas in tank thneedle moved about 1/8
inch. thanks for the help
 
I'm not sure if you have already gone and bought your parts, but have you checked to see if your gas gauge is the culprit? It's an easy and free way to make sure you aren't buying a sending unit for no reason.

Pull the little wire off the sending unit and stick another piece of wire inside of the connector and ground it to the chassis. Have someone look at the dash and see if the fuel gauge moves from E to F. If it does then it's your sending unit at fault. If it doesn't move correctly then you might just need a new gauge.

I just pulled an original sending unit out of a 67 Valiant. The sock was completely gone but the brass float and everything looked great. So pull the sending unit if you have to and see what it looks like. You can buy the float and/or sock separately to save money if the rest of it is in good shape.

Thanks, I missed this earlier. I'll try that
 
I have replaced the sending unit, wire, and guage for my fuel system in my 74 dodge dart. when i fill it up it reads 3/4 and is on the E about 4-5 gallons later. Can anyone help me here?
 
I replaced my fuel pump twice before I realized I was sucking a bunch of garbage into it. I pulled the sending unit to find the sock missing and lots of crud in the tank. I have since cleaned the tank, replaced the sending unit, along with its new screen/sock and another new mechanical pump. Everything is working great now.
 
hi I am looking for a place to buy a gas tank for my 71 dart swinger, the sender does not work, and. there is a dent in the tank just below the sender the local places want around 300dollars can they be found for a chaeper price? thanks


The spectra tanks from Rock Auto are nice, I think mine was 140.
 
I have replaced the sending unit, wire, and guage for my fuel system in my 74 dodge dart. when i fill it up it reads 3/4 and is on the E about 4-5 gallons later. Can anyone help me here?

Poor ground, or resistance is off in the gauge. Do all your other gauges
work well? Rallye dash or standard?
 
All of the other guages work fine. The alternator guage swings back and forth until the engine picks up RPMs, but thats it. I havent looked into the guage or anything. i dont exactly know what i would be doing there.
 
Hey everyone, sorry to drag this thread out of the shadows but I am having a related problem.
74 Dodge Dart Swinger 318 that is only taking 4-5 gallons. The pump shuts off and we can't fill anymore. My son normally drives it and the other day he ran out of gas (teens). He was only able to put in 5 gallons. What should I be looking for here?
 
Hey everyone, sorry to drag this thread out of the shadows but I am having a related problem.
74 Dodge Dart Swinger 318 that is only taking 4-5 gallons. The pump shuts off and we can't fill anymore. My son normally drives it and the other day he ran out of gas (teens). He was only able to put in 5 gallons. What should I be looking for here?

Have him try holding the gas pump nozzle upside down when filling the tank.
 
Well, if the fuel tube pick up has a hole in it that's up high, that Is a possible. Not a big deal to remove it and check.
 
Hey everyone, sorry to drag this thread out of the shadows but I am having a related problem.
74 Dodge Dart Swinger 318 that is only taking 4-5 gallons. The pump shuts off and we can't fill anymore. My son normally drives it and the other day he ran out of gas (teens). He was only able to put in 5 gallons. What should I be looking for here?

Look under the car to see if the tank is crushed. Sounds like the vent is plugged. Some type of mud-packing insect did it to mine and a friends locally. Not fun to clean out, but it's also a low-tech process once you locate the tube.

I too have to flip the vapor recovery nozzles upside down to fill my tank. It always dumps a cup of fuel on the ground without warning when full. In Nevada, they don't have vapor recovery nozzles and there is no issue. California Lib's are always using a sledgehammer to fix a Swiss watch.
 
No visible damage to the tank. I'll be checking the vent and other things probably this weekend. I like working on cars, but between this and the blown head gasket on my WRX it is getting pretty frustrating.
 
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