matchek

My fuel sending unit is bad. When I replace, it was advised to replace the tank.

Any thoughts on who sells new gas tanks to fit the full size body? Original has 25 gallon tank. Would there be any harm in replacing it with a larger volume tank, say 30 gal, if it fit? This would help on longer trips.

oldcutlass

Who advised on tank replacement? If its clean and serviceable why? A larger tank requires more room, if you have the room I see no issues.

MDchanic

+1.

Why would you replace a perfectly good tank?

Where would you get a larger tank than the one that's designed for the car?
How would it fit in the same space?
What on earth has a larger tank than 25 gallons, other than a heavy duty pickup truck or a semi?

- Eric

Allan R

Hmm, seal the trunk and line it, add another 250 gallons. Are you kidding me? Even if the old tank has a minor leak it can be cleaned, repaired and interior coated to function just as new.

matchek

The mechanic suggested it as the car sat for long periods of time , before I got it, hence the sending unit is stuck.

The outside looks rusty and there was an assumption the inside was too , due to sitting.

If the price was right I was considering it when I have the sending unit replaced.

250 gallons - now were are talking!!!!!

MDchanic

Possibly but not necessarily.
You'll know when you take the tank down and remove the sender, and then you'll be able to make an informed decision.

- Eric

Allan R

Most tanks that are that old will have some surface rust, but that's not going to harm the tank. Sender units can fail simply due to age, and replacing that is likely going to cure your major problem.

Going on a mechanics suggestion to replace it based on that? Using the same logic, you should be replacing your frame, brake lines, fuel lines, rad support, body sheet metal, floor pans, trunk pans etc. Please don't get carried away with a 'suggestion' from a mechanic. A lot of them nowadays don't understand old car technology and are used to seeing plastic fuel cells.

You'd be surprised how thick the metal is on those tanks, and if I'm not mistaken, they are also made from high strength ni tern steel. Pull it and have a look before proceeding any further. Likely the worst case scenario is you'll need it to be steamed and dried inside. The outside can clean up in the light acid bath they use for this and you can either coat it or paint it afterwards.

You might even be surprised to find a build sheet on top of the tank when it comes out.

Yellowstatue

Robert Mitchum did not have a problem installing a larger tank!!!

joe_padavano

First, you'll have trouble finding a new stock replacement tank, never mind an oversize one. Second, keep in mind that the tank configuration and mounting are designed to comply with crash safety requirements. Yeah, I realize that the older tank mounting under the trunk is not nearly as safe as new cars with the tank in front of the rear axle, but the fact remains that any changes you make without proper engineering run the risk of increasing injury in a crash. Your car, your life, your call.