Salvaging fuel tank crossover tube.

[Sunnyledge]

As the fuel tank on my 84 318i is shot I purchased a new aftermarket tank. I then realized that removing the crossover tube from the old tank was going to be a problem. When I saw that a new crossover was going to cost $145-150, I was determined to find another solution. I searched the internet and found one solution which was to purchase new M16 x 1.5 swivel fitting with a hose connection and use 8 mm fuel hose for the crossover. I ordered the fittings from a vendor in England for under $12 shipped. But I decided to see if I could salvage the old tube. I filled the old tank with water and cut the tank fittings off with the crossover tube still attached. I clamped the tank fitting in a vise, applied heat was able to separate the crossover tube from the tank fitting. But the compression nut was still frozen on the crossover tube. I tried soaking it in Evaporust to see if it would free up the nut. In this case it didn’t. I carefully cut the compression nut off each end of the conical connector with a dremel tool. Next I cut the crossover tube in half, slid on new compression nuts, aligned the tubes using the new tank. I then reconnected the tubes by sweating a $3 brass coupling from Home Depot drilled out to 13/32”. Total cost $15 and about 2 hours labor.

[roguetoaster]

Good stuff, not 100% sold on the soldered coupling, but I suspect that it will be fine.

[nrubenstein]

For what it is worth, I have found that you can reinstall if *one* of the nuts is frozen.

That said, I was able to find a nice one from California for pretty cheap, so i went that route when I replaced the tank in my M3.

[AndrewBird]

You could probably use rubber fuel hose to join them back together if soldering is not an option. There isn't pressure in that line, so it should last long time.