78 fuel tank question??
Thread Starter
Racer
Joined: Sep 2010
Posts: 259
Likes: 1
From: Mt Airy, NC
78 fuel tank question??
I,m to the fuel tank on my resto and got all gas out and noticed there is a plastic tank on the inside of the metal tank. There is gas trapped between the two tanks. There dosent seem to be any holes in the plastic tank. How did this gas get in there? Is there definitely a hole in the plastic tank? There is a cavity in the plastic tank under the vent line. Could gas over time have sloshed to this cavity? I'm not wanting to shell out 250 for a tank if I dont have to for mine seems ok other than this mystery. Any advice would be helpful.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
If you have fuel between the tank and the bladder then you have a hole in the bladder. The bladder was one giant lining inside the take and part of a safety re-vamp by GM.
Can you remove the bladder.. I've never tried it but from what I understand it can be done. You'll need to save the very top of it that seals the neck to the tank but it can be done.
If you leave the fuel behind the bladder over time it will grow stale and enter the fuel system. Another issue that fuel behind a bladder can cause is an incorrect fuel reading. Not because the fuel is behind the bladder but because as it grows behind there the bladder will usually push inward and hit the sending unit arm float.
Willcox
Can you remove the bladder.. I've never tried it but from what I understand it can be done. You'll need to save the very top of it that seals the neck to the tank but it can be done.
If you leave the fuel behind the bladder over time it will grow stale and enter the fuel system. Another issue that fuel behind a bladder can cause is an incorrect fuel reading. Not because the fuel is behind the bladder but because as it grows behind there the bladder will usually push inward and hit the sending unit arm float.
Willcox
Melting Slicks
Joined: Aug 2004
Posts: 2,914
Likes: 229
From: Oakbank Manitoba
If you have fuel between the tank and the bladder then you have a hole in the bladder. The bladder was one giant lining inside the take and part of a safety re-vamp by GM.
Can you remove the bladder.. I've never tried it but from what I understand it can be done. You'll need to save the very top of it that seals the neck to the tank but it can be done.
If you leave the fuel behind the bladder over time it will grow stale and enter the fuel system. Another issue that fuel behind a bladder can cause is an incorrect fuel reading. Not because the fuel is behind the bladder but because as it grows behind there the bladder will usually push inward and hit the sending unit arm float.
Willcox
Can you remove the bladder.. I've never tried it but from what I understand it can be done. You'll need to save the very top of it that seals the neck to the tank but it can be done.
If you leave the fuel behind the bladder over time it will grow stale and enter the fuel system. Another issue that fuel behind a bladder can cause is an incorrect fuel reading. Not because the fuel is behind the bladder but because as it grows behind there the bladder will usually push inward and hit the sending unit arm float.
Willcox
Don't feel bad. Your tank lasted 33 yrs. Get a new one for piece of mind.
Last edited by KENS80V; Jun 3, 2011 at 09:43 AM.
Thread Starter
Racer
Joined: Sep 2010
Posts: 259
Likes: 1
From: Mt Airy, NC
His tank is from a 78 which doesn't have a bladder (78 to 82 are the same). It has a hard plastic liner (high density polyethylene). They cannot be removed. The liner dry rots over time and will develop cracks. There is no replacement tank available with this liner. All the current replacement tanks are just steel with no liners or bladders.
Don't feel bad. Your tank lasted 33 yrs. Get a new one for piece of mind.
Don't feel bad. Your tank lasted 33 yrs. Get a new one for piece of mind.
but I'm going to attempt to cut this tank out with a razor knife and snips, clean inside of metal tank, seal with por15 tank sealer. If anyone knows this wont work please let me know
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
His tank is from a 78 which doesn't have a bladder (78 to 82 are the same). It has a hard plastic liner (high density polyethylene). They cannot be removed. The liner dry rots over time and will develop cracks. There is no replacement tank available with this liner. All the current replacement tanks are just steel with no liners or bladders.
Don't feel bad. Your tank lasted 33 yrs. Get a new one for piece of mind.
Don't feel bad. Your tank lasted 33 yrs. Get a new one for piece of mind.
But I can't imagine trying to remove one myself.
