August 2003: Part 1 - Gas Tank Rebuilding

Part 2: Rear Suspension From The Ground Up

Well, TII gas tanks are no longer available - Sadly, I was about 2 years late ordering one. After finding out the NLA bad news, I was hoping that this tank was ok.  The notes I had on this car showed it was replaced about 10 years ago with a new one.  This view shows what is unique about the TII tanks - they have two openings - one for a outbound and inbound fuel flows, the second measures how much gas is in the tank itself.
Once out of the car, you could see where the trouble was starting to be discovered.
Some bad rust... why should I not be surprised? BMW's original foam gasket design held water in this location so they all rusted, along with the car. The tank will be taken now to a commercial metal stripper for preparation.
I learned while doing the body that any area you don't want the beads to hit you mask off with serious duct tape. I pulled the guts out of the strainer mechanism and built a cardboard gasket. It was bolted down using the original screws, and then masked with duct tape.  More on the tank later...
The strainer inside pulls fuel from this filter, which is on the bottom of the tank.
This is NOT how one should look - it's clogged with lots of rust particles. This is due to the car setting for about 10 years with fuel in it - nasty stuff which clogged the fuel filter and made the car stall out.
Holding it up to the light, you see how bad it is. Order yourself a couple of these, just in case!
Inside the tank, the residual rust is easily seen.
In fact the rust is... everywhere. This will now get boiled out by a radiator shop.
Most radiator shops will do this for you for a reasonable fee. Have it sealed up if the shop can do it.
OK, here's the tank after bead blasting and then coated with 2 coats of POR-15 silver with a foam brush. You've read about this stuff, here it is in action. To purchase POR-15, just visit their site at I plan on painting this back to black when done, this will be like the "armor plating" that will keep the tank like new for it's next lifetime. There was no more rust on the outside when the bead blaster had it's way with this tank. I neglected to take a photo before I started, but you didn't miss anything really.
On advice from my metal stripper, I'm coating the POR-15 first to the outside before taking it to the radiator shop. The POR15 will hold up like armor plating in the boil tank, since POR15 is strengthened by moisture. The only thing that will be affected will be the inside of the tank.
This stuff is really strong when dry - much harder than paint or powder coating.
Luckily, this tank is not destroyed by rust pinholes. To make sure it won't happen again, I'm using POR-Patch, which is similar to JBWeld cold weld products. I have sealed up the entire outside edge with the patch material, so it should never rust or leak again unless it is physically damaged. The rough edges you see here have been completely sealed up, and are not seen when installed into the trunk.
Next steps are boiling out, sealing the inside with POR-15 tank sealer, and then final primer and painting. It should be as good as new. I have ordered a few of the other parts that complete this section of the car and I'll cover off on that in coming weeks ahead.
---> ON TO PART 2 -->



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