Fuel Tank Design
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 3,270
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From: Winchester VA
Cruise-In V Veteran
Fuel Tank Design
I have read more than once on this site the our fuel tanks have an inner bladder. I have an 85 and I have looked in the tank a few times (fuel pump replace, fuel pump upgrade, fuel sender repair) and I really don't think I see a bladder.
I fixed a leak in the bottom of the tank with tank repair stuff and appear to have developed a couple more pinholes since.
My question is, if there is a bladder, why would the pinholes leak? Did the bladder come in later years maybe?
I guess my bladder could be compromised as well, but I'm REALLLY having a hard time seeing the bladder.
I searched MAM and Zip real quick for replacement and did not see one. I need to keep looking obviously but I think a fuel cell may actually be a cheaper way to go. (I have an external pump sitting on the shelf and a bunch of leftover fittings and such)
I fixed a leak in the bottom of the tank with tank repair stuff and appear to have developed a couple more pinholes since.
My question is, if there is a bladder, why would the pinholes leak? Did the bladder come in later years maybe?
I guess my bladder could be compromised as well, but I'm REALLLY having a hard time seeing the bladder.
I searched MAM and Zip real quick for replacement and did not see one. I need to keep looking obviously but I think a fuel cell may actually be a cheaper way to go. (I have an external pump sitting on the shelf and a bunch of leftover fittings and such)
Race Director
Joined: Jun 2004
Posts: 13,956
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From: WI
My '88 does not have a bladder, it's just one big metal tank. I think they are zinc coated on the inside so if you fix some holes, re-coat it. I've been tempted to use a fuel cell for less weight but it would mean more work as well, fueling up more often. I can run a track day with only fueling once with the stock tank.
Race Director
Joined: Apr 2003
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From: moraga ca
My '88 does not have a bladder, it's just one big metal tank. I think they are zinc coated on the inside so if you fix some holes, re-coat it. I've been tempted to use a fuel cell for less weight but it would mean more work as well, fueling up more often. I can run a track day with only fueling once with the stock tank.
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
All cars made in the last few decades have had to have a bladder within the tank (think Pinto). This decreases the chance of fuel leakage and possible explosion in case of an accident. This is a picture of my 84 tank which I sectioned in 3 pieces in order to remove it without having to remove the bumper. I replaced it with a fuel cell. The hardest part of sectioning the tank was cutting through the 3/8 inch bladder within the tank. The bladder is the black liner you can see if you look carefully where the tank was cut.
What is the bladder made of? I'm guessing some sort of rubber
Any pics of your fuel cell install? Which one did you use?
I want to retain as much of the range as I can and would be looking at a 16-20 gallon with sump. Summit has one for 169 that includes the foam and sender.
Race Director
Joined: Jun 2004
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From: WI
Last week I changed my fuel pump and it is not black like that in my tank. I can't see why they would be different though. Mine was gray and I reached in to grab a small piece of debris, the bottom felt like metal.
Race Director
Joined: Apr 2003
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From: moraga ca
At the bottom of the tank is a plastic tray which is hard. Look around it. The tank has a bladder.
Race Director
Joined: Apr 2003
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From: moraga ca
Thank you!
What is the bladder made of? I'm guessing some sort of rubber
Any pics of your fuel cell install? Which one did you use?
I want to retain as much of the range as I can and would be looking at a 16-20 gallon with sump. Summit has one for 169 that includes the foam and sender.
What is the bladder made of? I'm guessing some sort of rubber
Any pics of your fuel cell install? Which one did you use?
I want to retain as much of the range as I can and would be looking at a 16-20 gallon with sump. Summit has one for 169 that includes the foam and sender.
Race Director
Joined: Jun 2004
Posts: 13,956
Likes: 706
From: WI
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Race Director
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From: moraga ca
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
I'm with you Aardwolf...I tried real hard to see/feel a bladder and you really can't tell. If I hadn't seen the cutaway...
This is interesting though because in order to get a leak then, the tank would have to rust and the bladder break.
Is there room between the bladder and the tank for moisture to build up?
It seems odd now, but I don't think I confirmed it was fuel dripping from the hole. I saw fluid dripping and ran right to the store for a repair kit. Since I found it while doing fuel pump work, the smell of gas was already prevelant.
This is interesting though because in order to get a leak then, the tank would have to rust and the bladder break.
Is there room between the bladder and the tank for moisture to build up?
It seems odd now, but I don't think I confirmed it was fuel dripping from the hole. I saw fluid dripping and ran right to the store for a repair kit. Since I found it while doing fuel pump work, the smell of gas was already prevelant.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
I'm with you Aardwolf...I tried real hard to see/feel a bladder and you really can't tell. If I hadn't seen the cutaway...
This is interesting though because in order to get a leak then, the tank would have to rust and the bladder break.
Is there room between the bladder and the tank for moisture to build up?
It seems odd now, but I don't think I confirmed it was fuel dripping from the hole. I saw fluid dripping and ran right to the store for a repair kit. Since I found it while doing fuel pump work, the smell of gas was already prevelant.
This is interesting though because in order to get a leak then, the tank would have to rust and the bladder break.
Is there room between the bladder and the tank for moisture to build up?
It seems odd now, but I don't think I confirmed it was fuel dripping from the hole. I saw fluid dripping and ran right to the store for a repair kit. Since I found it while doing fuel pump work, the smell of gas was already prevelant.
Race Director
Joined: Jun 2004
Posts: 13,956
Likes: 706
From: WI
I wonder if someone pulled the bladder out of mine. I was groping around in there picking up debris and really would have noticed a loosely attached bladder. I looked specifically for the bladder because I had read there was one. A PO had replaced the fuel pump in mine and had wires twisted together and taped, plus copper shreds of wire down in the tank. It was a hack job so I was fixing it up. So anythings possible there. 
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
I wonder if someone pulled the bladder out of mine. I was groping around in there picking up debris and really would have noticed a loosely attached bladder. I looked specifically for the bladder because I had read there was one. A PO had replaced the fuel pump in mine and had wires twisted together and taped, plus copper shreds of wire down in the tank. It was a hack job so I was fixing it up. So anythings possible there.
