HawkIVette

I need to replace the Gas tank on my 75 this winter. I can only get about 12 gallons of fuel in the so called 18 gallon tank. I remember Paul Borkowski saying something about the bladder separating from the tank in his 75 and removing the bladder.
If I have to take the tank down to remove the bladder, I figured I might as well replace the tank, fuel lines , and anything else back there.

Can somebody who has had experience with tank replacement, guide me to a article on how to do this or give me advise via post or e-mail. Also would like to know what parts I should order other than tank.

Thanks in advance.

wombvette

I dont think a 75 has a bladder.

ScubaJKD

Your on the right track to replace the tank. I originally set out to vat and seal mine and once it was all cleaned up it leaked like a pasta strainer. By the time I did all that I could have bought a replacement tank for not alot more money. Replace that puppy and dont look back. Also lots of people recommend coating the inside with a sealer made for gas tanks. While replacing mine I replaced the sending unit and little filter sock thingamajig. Corvette Central had some good diagrams that I worked from to see all available parts to replace. While you are in there do it right and do it once. Its a pain in the arss removing that tank so get it all while you are there. Hope this helps

:seeya

lyonsh

The factory service manual has a pretty good explanation of how to drop the tank. It's a pretty straightforward process; just remember you have lines on both sides of the tank (fuel lines on the passenger side, vapor line on the right). Installation is in reverse. It was actually more trouble for me to get everything out of the way (exhaust, spare tire carrier) than it was to drop the tank.

Just remember to run or siphon it dry before you drop it. You also might want to get new straps for the tank. Mine were pretty well stretched by the time I got it off.

HawkIVette

wombvette,

I'm assuming it has a bladder from what I've heard from other 75 owners, and also no other explaination why I can't get anymore gallons in than 12 or so.

Lyonsh,

Are you refurring to the assembly manual when you say Service manual. I have one of those and it does show some pretty good diagrams. Does the fuel tank cover have to be removed too, or can it stay in place?
I'm assuming I'll have to remove the front tank support to drop the tank. Looks like it is bolted to the frame. After removing the tank support and straps, will the tank roll forward and down? How far can you lower the tank to access the lines?

Thanks again for the help.

Paul Borowski

Rich, all you need to do is completely take out your '75's tank, remove the top access panel which contains the fuel pickup and float sending unit mechanism. Be careful about removing this panel with the float as if the bladder is collapsing over it, it could break as your pulling this assembly out. It may or may not do this, just be aware it can. Once you've removed this panel assembly, you'll see how the bladder at the neck forms the gasket for this same panel. Simply cut the bladder at the neck creating and leaving a nice 3/4" wide gasket for the panel to re-install it. Simple to do, had mine done in less than one hour. One other great thing is Quanta is now making the '75-'77 fuel tank WITHOUT the bladder, which this way it's not needed any how. After doing this, your car WILL seem to get better mileage too because you're not putting gas into it as much!!!! :lol: :lol: :lol:

My '75 has been a "bladder delete" Corvette(very rare)since 1994 and has been great since. :) :) :)

lyonsh

1.Actually, I was referring to the Service manual. The Assembly manual has good diagrams, but the Service manual tells you what you have to take off to get to the tank.

2. I was able to reach up between the frame and body and disconnect the lines before I dropped the tank. But mine's a 72 - also, I don't have a fuel tank cover, just a plastic piece on the back of the tank between the tank and straps (Pinto's weren't the first cars with the low-tech anti-exploding fueltank devices :lol: ).

3. Yes, once you take the straps loose and unbolt the crossmember, the tank rotates down and forward for removal.

Paul Borowski

The lines are on top of the tank from '75 to '77-probably the same '78-'82. Slightly lower the tank, rotate downwards towards the front of the car, then you'll see and be able to disconnect the lines. Also, DO NOT have a light bulb near that could burst and explode!!! Use either a flashlight, or flourescent(sp?)light that is enclosed. I emptied my fuel tank by hooking up a four foot line coming off of the return line(small line) and emptied into a five gal can. Turned the car off just as it was starting to "sputter". :yesnod: