Fuel tank install question

[JFLLincoln]

Hi all, I've been chasing a fuel odor issue that has had my 1971 2800CS banished from the (attached) garage... after replacing all fuel hoses, tank level sender O-ring and the electric fuel pump I finally pulled the tank and sent it out for the "Renu" treatment.

Questions of the day:

What is the "right" material to use at the seating surface between the tank flange and the trunk surface? The BMW service manual refers to "foam rubber underlay" (page 16-11/2)...

The manual (same page reference) refers to a "cord ring seal" on the tank level sender (manual calls it the "tube level indicator") and the photo points to just inside of what looks a rubber o-ring...I thought that for this (carbureted) car there was just the one o-ring... does anyone know if there is supposed to be more than just the one o-ring on this assembly?

Thanks in advance...

Jim

 

[bavbob]

I can tell you what I used,

 

[JFLLincoln]

Thanks Bavbob!

 

[OCCoupe]

The correct material is the part # 16111117053 which is supplied by BMW. This is a foam weather strip with an adhesive backing. Unfortunately this material is the reason that so many tanks fail at the seems. The foam doesn't create a perfect seal and retains water which causes the tank to rust.

I used 3m Strip Caulk which is easy to work with and spreads out once you tighten down the bolts that hold the tank in place.

 

[bavbob]

Make sure you have your charcoal canister hooked up and the plastic line from the tank neck to the canister is intact. This is a cause of gas smell in the cabin.

The ice shield is nothing more than the 3M strip caulk on steroids. I do love the strip caulk and use it on everything else....it's next to my bottle of Frank's Red Hot. Yea, the original BMW sponge was a major design flaw. I had to rebuild the entire trunk flange even before I put in a refurbished tank.

 

[JFLLincoln]

Thanks and a further question re charcoal canister...

Thanks for your insights Bavbob and OCCoupe... yeah, the open-cell foam seemed like a bad idea to me when I last had the tank out (~1987???) and I went with some manner of solid rubber extrusion... the 3M caulk strip looks like a cool thang, will need to try that.

Bavbob, regarding the charcoal canister, I see the vent line off the fuel filler neck, it goes to a plastic expansion tank which is in turn connected to a braided rubber line that disappears into the passenger compartment... haven't chased it forward yet but have always assumed it went to the charcoal canister... was thinking of replacing this whole line... have never laid eyes on the charcoal canister... thoughts on location appreciated (someplace in engine compartment???

 

[Stevehose]

+1 on the 3M caulk I use it a lot also.

The cannister is under the battery tray.

The vapor line comes out on the passenger fire wall then goes across it to the drivers side then to the cannister.

You'll have to pull out your interior to replace the line.

I vented mine out the trunk floor and capped off the tank and lines.

 

[Honolulu]

Jim, before you touch the fuel smell tar baby, know that there are numerous reasons for fuel odor in the passenger compartment and they have been discussed repeatedly on this forum. The Search function should turn them up.

To the list of suggestions I will add one more: "They all do that."

Know before you go!

HTH

 

[bavbob]

From canister under battery tray, the line runs to the air filter housing. The line is made of rigid plastic that cracks over the years. Usually the problem is neck to expansion tank.