Bottom Mounted Fuel Tanks

[JMinPDX]

Gruppe,

I removed fuel tank from my 74 CSA a few weeks ago. It came out from under the car. Two brakets bolt underneath and hold the leading edge lip of the tank and two bolts go through the lip on each side and screw into the edge of the tank opening.

The manual says the tank is removed from inside the trunk. Does any one know when this changed? Will the "lift out" earlier tanks fit my car.

Realoem has no listings for the two brakets. Also, on my tank the filler neck and tank are one piece. There is no hose conection to the filler neck. Realoem shows the two piece tank/neck for my car.

I have my tank at a shop that will totally clean fill rust holes (my tank has a dozen pin holes) and reseal it for $350.
It will be as good if not better than a new one. http://www.gastankrenu.com

Before I give them the go-ahead I was wondering if any year e9 tank would fit my car

John M

 

[AndyM]

The change to the bottom mounted tank took place around the 74 model year. unfortunately, the two tanks are not interchangeable.

 

[bert35csi]

I had an old fuel injection coupe tank "renu" by their Northern California franchisee a few years ago for about the same amount and am pretty satisfied with the results. The tank coating both inside and out has a really wrinkly and textured appearance. I had asked them to paint the tank exterior with an oem liked satin black paint, initially, they said no problem, but later on, through some mumbo jumbo, they insisted it cannot be done. This notwithstanding, the resealed tank does look like new. One caveat though, due to the thicker coating of the "renu" tank, the bayonet sender units will be a lot harder to mount. The tank still sits in my garage and has never been mounted so I can't attest to its sealing properties.

As AndyM stated, the changeover point from topside to bottomside tank mounting probably occurred with the 74 cars for both carb and FI tanks.

 

[AndyM]

By the way, I suspect your pin holes are right along the mounting flange. BMW used open cell foam to seal the tank to the body which creates a nice water trap. My otherwise rust-free car had numerous holes in the tank right along that seam. I patched it with JB Weld (not recommended) which held for a few years until I found an OEM CSi replacement tank. The price I paid makes your estimate seem completely reasonable. Be sure to used closed cell foam to seal it to the body.