Fuel Tank Question

TimAT

TimAT

Addict, Cruise-In Bird-Run 1 Veteran
Joined
Mar 24, 2008
Messages
1,969
Location
Gladstone, Missouri
GM used bladders in the fuel tanks on some years, then went to a plastic liner, before that they were just a sheet metal tank. What years did they do what? I know 69 is just a steel tank, but what about the 77? Bladder? Rubber? Liner?
 
77 has a bladder, I think it's 73-up for the bladders. 78-82 has a plastic tank with a steel outer shell. 69 is just a steel tank for sure.
 
Looks like it may be a bladder tank from what you guys are saying. I read somewhere that they don't have any new or repro bladders, so what are the options? Full on fuel cell or will some other tank fit? No leak, but the gauge is reading all wacky- 1/2 tank of gas on the gauge and add less than 7 gallons and it's showing full. I haven't really looked since I haven't been home, but that is the report I got. Kind of sounds to me like the bladder is collapsing - that's the reason i'm asking. catch this before it becomes a real problem.
Or if anyone has a fix- post that!!
Thanks,
 
TimAT said:
Looks like it may be a bladder tank from what you guys are saying. I read somewhere that they don't have any new or repro bladders, so what are the options? Full on fuel cell or will some other tank fit? No leak, but the gauge is reading all wacky- 1/2 tank of gas on the gauge and add less than 7 gallons and it's showing full. I haven't really looked since I haven't been home, but that is the report I got. Kind of sounds to me like the bladder is collapsing - that's the reason i'm asking. catch this before it becomes a real problem.
Or if anyone has a fix- post that!!
Thanks,
Click to expand...

Typical chevy/gm gas gauge reading. They read full for the first 100 miles then drop like a stone. Put a few gallons in and the gauge (incorrectly) reads full again. My 95 Firebird was like that.
 
Last edited:
DeeVeeEight said:
TimAT said:
Looks like it may be a bladder tank from what you guys are saying. I read somewhere that they don't have any new or repro bladders, so what are the options? Full on fuel cell or will some other tank fit? No leak, but the gauge is reading all wacky- 1/2 tank of gas on the gauge and add less than 7 gallons and it's showing full. I haven't really looked since I haven't been home, but that is the report I got. Kind of sounds to me like the bladder is collapsing - that's the reason i'm asking. catch this before it becomes a real problem.
Or if anyone has a fix- post that!!
Thanks,
Click to expand...

Typical chevy/gm gas gauge reading. They read full for the first 100 miles then drop like a stone. Put a few gallons in and the gauge (incorrectly) reads full again. My 95 Firebird was like that.
Click to expand...

Matter of fact, when discovering that water in tank problem, I rebent the float rod to get away from most of that....I use a stick to measure depth of gas and compare to the gauge, i'ts reasonably accurate now....

:amazed:
 
If it was just me, I wouldn't be a little worried at all. This is the 77 I got for my bride. If she runs out of gas 'cause the gauge is not correct, it's going to be painful. She just told me about it so I'll have to figure out whats going on when I get home. She's already got a "honey-do" list for the car. And that for just the things she's seen. Add that to the list that I have for the car, and then the lists for the house and yard. :rose:
 
TimAT said:
If it was just me, I wouldn't be a little worried at all. This is the 77 I got for my bride. If she runs out of gas 'cause the gauge is not correct, it's going to be painful. She just told me about it so I'll have to figure out whats going on when I get home. She's already got a "honey-do" list for the car. And that for just the things she's seen. Add that to the list that I have for the car, and then the lists for the house and yard. :rose:
Click to expand...

So got to WORK, :clobbered::bounce:
 
I cut my bladder out with no problems. Tank was good.
Be a good time to install an aircraft sump drain and R&R all the hoses. I also soldered the ground wire pigtail to the housing. Cut and use the bladder for the tank mounting pads.
 
My 74 doesn't have a bladder so it must of been 75 that it changed. Why not just put an older non bladder tank in?
 
That's exactly what will happen if (once I get home to look at it) I find a problem with the bladder. I'll stuff the biggest capacity tank I can get in there. NMP

:hunter:
 
Tim
I cut out the 75 bladder a few years ago, I use the neck flange for the gasket but the tank is fine without it. Yes it was an impact safety feature, ala Pinto's of the period.
I don't believe they are reproduced at this point but again we've run without for years now.
 
GTR1999 said:
Tim
I cut out the 75 bladder a few years ago, I use the neck flange for the gasket but the tank is fine without it. Yes it was an impact safety feature, ala Pinto's of the period.
I don't believe they are reproduced at this point but again we've run without for years now.
Click to expand...


Wow, I know you think i'm a yahoo for some of the shit i do. Well, everybody does.


This is something i'd never ever do. I can handle a spindle coming loose and going head on into an 18 wheeler. I can't handle burning to death slowly.

But no, The point is it's funny what some people think is important and not important and apparently it varies widely.
 
Interesting and valid point there Turtle-

I've looked under the 69- steel tank- no barrier or anything between it and the passenger compartment- and no federal mandated crash bumper. Anything pops that in the ass and it's bath in gas time.

The 77 may have the bladder in the tank (I don't know for sure yet) but right ahead of the tank is a sheetmetal plate that runs from over the top of the tank down to the lowest crossmember. AND a crash bumper.

Just from looking at those 2, I'd have to say that it's 90% federal regs and 10% safety.

The only real fix for any of this is a full on race type fuel cell with the supression foam in it. Seems like overkill for a street driven car to me. Heck, you can get run over by a bus going to the grocery store.
 
TimAT said:
Interesting and valid point there Turtle-

I've looked under the 69- steel tank- no barrier or anything between it and the passenger compartment- and no federal mandated crash bumper. Anything pops that in the ass and it's bath in gas time.

The 77 may have the bladder in the tank (I don't know for sure yet) but right ahead of the tank is a sheetmetal plate that runs from over the top of the tank down to the lowest crossmember. AND a crash bumper.

Just from looking at those 2, I'd have to say that it's 90% federal regs and 10% safety.

The only real fix for any of this is a full on race type fuel cell with the supression foam in it. Seems like overkill for a street driven car to me. Heck, you can get run over by a bus going to the grocery store.
Click to expand...

I was going to comment about Linda's Miata, talk about paranoid....:clobbered:

and I have thought of that vette tank also, but other than that fuel cell....

but then again...you know an old friend from some time ago....Chris McDonals, 68myway, used to live down the street a bit here in OP, anyway he is doing another killer, and so was thinking of a rear trunk on a shark, ala C5 type gig.......so that obviously means lowering the gas tank...

which means may as well do a fuel cell and have over with it....sticking a plate of metal in front for extra protection maybe?? anyway, it would pick up a good amount of capacity...say 26 gallons and with that trunk on there, hummmmm.....

:bump:
 
TimAT said:
Interesting and valid point there Turtle-

I've looked under the 69- steel tank- no barrier or anything between it and the passenger compartment- and no federal mandated crash bumper. Anything pops that in the ass and it's bath in gas time.

The 77 may have the bladder in the tank (I don't know for sure yet) but right ahead of the tank is a sheetmetal plate that runs from over the top of the tank down to the lowest crossmember. AND a crash bumper.

Just from looking at those 2, I'd have to say that it's 90% federal regs and 10% safety.

The only real fix for any of this is a full on race type fuel cell with the supression foam in it. Seems like overkill for a street driven car to me. Heck, you can get run over by a bus going to the grocery store.
Click to expand...

Just about everyone who has pulled their 75-77 tank has said the liner was in good shape. I wonder if its possible to CAREFULLY pump air into the tank to force the liner to expand back to the tank wall.

Or pull the tank and clean everything up, then goop up the outside of the liner with silicone sealant then expand the liner against the tank with compressed air until it sets up.
 
No idea if you can pull a Vette tank liner into shape, but we do it on big airplanes all the time- Pull a negative pressure on the tank and it'll open the bladder up like a flower. Not too much, only 2-3" vacuum. But then too, I'm talking about a tank that holds 6000 gallons.

I wouldn't bet against it that the bladder in the 77 is fine and it's not a ground/gauge problem. I'll just have to dig into it when I get home.
 
Got this in an email a while ago.
Don't know if the complete kit is a good deal or not. I think the only diff for the 74 tank is the larger regular gas neck.

BTW, apparently, having the spare tire installed was an important part of rear saftey.
 
You must log in or register to reply here.

Latest posts

Back
Top