My gas tank bladder seems to be collapsing on my '75. I'm aware that you've delt with this on your '75. I've yet to pull the tank. Can you give me any tips/advise on the bladder removal/repair. Is there any 'sealing' edges that must be left intact that I have to be concerned with?
Secondly, why is it vendors don't list a gas tank repl for the '75. Is it just because of the bladder, or is there other unique features of this yr tank?
Others feel free to chime in with your experiences. Thanx -Rod

 

Rod, this is very easy to do. I did my '75's bladder removal back in '94. Quanta DOES NOW have the '75-'77 fuel tank, but it is the shell only(basically like a '74 tank, but fuel pickup and sending unit comes down from the top on these '75-'77 tanks). This '75-'77tank, if reproduced in stock form with bladder, would probably be over $500 by my guess. Drop your tank, carefully remove that top access panel where all your lines are connected to(be careful to maybe unconnect the lines as you partially lower and tilt the tank towards front of car for access to these lines). Once you have this "top access panel" removed(as I said, do it carefully, the bladder being distorted, may want to keep the float and pickup from coming out. Work with it gently and carefully, it'll come out)you'll see how the "bladder" forms a gasket between this panel and the tank itself. Simply neatly cutoff the bladder at the tank opening making a nice gasket, remove the bladder completely from tank, reinstall the panel back onto the tank carefully guiding in the fuel pickup and float, with gasket in between panel and tank and you now have a "bladder delete" 1975 Corvette-I've probably now put over 20,000miles on mine since it has been this way and it's worked like a charm. My '75 used to only hold roughly 13gals of fuel, now it holds it's regular 18-20gals, or whatever it is. Also, keep that thick bladder around. That material is very neat. I've used bits and pieces of it here and there for many different things such as jackstand pads!!! I was lucky, my tank was very nice on my car and I was able to reuse it this way. If your tank is really rusty or maybe not useable, you may want to get the Quanta "shell" and use all your hardware, top panel, etc. Easy project, take your time and it'll come out great. Also, work very safely around the fuel. To drain my tank completely, I hooked up a small hose on the fuel return line coming out of fuel pump back to the tank into a five gallon gas can til the car virtually ran itself out of gas. Good luck, keep us posted!!!

 

Thanks Paul! It always helps to get a heads-up from someone who's done it before! I like the idea of keeping the old material around for those 'odd' jobs!
My last fill-up sported a whopping 11 gals! Being the rear susp and exhaust is out of the vette right now, I figure now is as good as ever to tackle the tank also! I'm just gonna wait til the temps rise above this artic setting to drain the tank, as I don't favor running the heater while draining gas!! :nono: -Rod

 

Rod, seeing as your car is apart right now this won't happen to you, but what did happen to me in my '75 was that I was heading up to a "cruise-in" around Cleveland,Ohio and I ran out of fuel!!! Even though my gauge was showing over 1/4 of a tank, part of my "collapsing bladder" was underneath the float assembly holding it up and making it read like I had fuel when actually my tank went bone dry. Lucky for me, another friend heading up there with me in his '69 roadster saw me coasting off to the side of the road. He went and got 3gals of gas and it got me to the next station. :lol:

Another thing to do when you have the tank dropped and that is to change all three fuel lines back there. One is a fuel feed, another the fuel return and the last one on the driver's side is the vapor recovery line.

 

Thanks for the additional info Paul!
What would you recommend as a coating for a 'grungy' gas tank? The tank looks to be solid enough to reuse at this point. I would like to 'freshen-up' the look and protect it further. I know you're an NCRS guy, and that would be a no-no. But your experience seems to be vast with C3's, and maybe you've seen something on the market that works! Thanks again! -Rod :chevy

 

Rod, that is an area I'm not to familiar with. My cars are not "restored" cars. Yes, maintained and all, however I have'nt gotten into really "repainting or restoring" anything just yet. The time will come probably when I may have to change out the frame on my '68 down the road and I'll be getting into some of this stuff. Probably best thing to do is to post that exact same question and see what other C3 owners here have done. :yesnod: