Last Spring I finished rebuilding the engine on my '92 B2200 and after installing it and running it for a few days discovered the gas tank had a serious rust problem. The rust was plugging up the fuel filter. I put a new stock fuel filter on. Then I put one of those glass fuel filters between the tank and the new filter. It filled up with rust within 30 miles of driving. Fortunately the glass filters can be taken apart and cleaned, but I looked like a real dork sitting on the side of the road cleaning the rust out of it. I put the biggest fuel filter I could find in place of the little glass filter and that eventually filled up too.

I got prices from various auto parts stores for a new tank. NAPA could get me one for about $140.

After searching various B2200 forums I found that rusting gas tanks appears to be a problem for Mazda's, especially older ones that sit for awhile. I didn't want to buy a new tank and a few years later have it start to rust. My brother recommended installing a plastic tank, but they're too expensive and not readily available for B2200 long beds.

A few years ago I had a similar problem with the gas tank on my Honda motorcycle and solved it by using a kit that put a tough coating inside the tank. I did a lot of research on the internet and POR 15 seemed to be the best solution. After treating the tank I was amazed at how tough this stuff is. It solved the rust problem and after seven years the inside of the tank looks the same as the day I put the treatment in.

After doing current research on the internet, I found a new treatment on the market from KBS that appears to be the same as the POR 15 but a little less expensive and also highly recommended. The cost of the kit was $67 delivered. The kit comes with an industrial strength cleaner, an acid etch to get rid of the rust and coat the tank with a primer, and the actual coating. This is a lot cheaper than buying a new tank and I will never have a problem with rust again.

The gas tank has to be removed from the vehicle. All hoses, sending units, etc. have to be removed from the gas tank. You can use duct tape to seal up the openings.

I started by using the cleaner to get rid of any varnish and residual gas in the tank. After rinsing the tank thoroughly with a garden hose, I moved on to the acid etch step to get the rust out.

My tank was rusted really bad, so I went to Home Depot and got a quart of cement etching solution, which is mainly phosphoric acid, mixed it 1:1 with water, and sloshed it around in the tank. I learned the hard way not to seal all the openings in the tank when using the acid etch. Fortunately I was holding the tank with the openings away from me when it literally blew the tape off the largest opening (where the sending unit was) and sprayed acid all over the car port. What a mess. Baking soda neutralized the acid and I rinsed it off with the garden hose. I took the tape off the small vent tube on the top of the tank, got some more acid etch, and finished derusting the tank. BTW, don't breath the fumes coming out of the tank - this could be very hazardous to your health. At this point I filled the tank with as much water as I could lift, to dilute the acid in the tank. I flushed the tank with water until all the acid was out. The kit comes with rubber gloves - use them!

I then put the kit's acid treatment into the tank and continued as directed by the instructions. After rinsing all of the kit's acid out of the tank it is necessary to get the tank totally dry. The coating will not adhere to any part of the tank that is wet. I hooked up the hose on my Shop Vac to the outlet side, sealed it into the filler opening on the tank with duct tape, and let it run for 8 hours.

It was totally dry and ready for the coating. The kit comes with a quart of coating and this is plenty. After moving the tank around and making sure every surface inside the tank was coated, I emptied as much of the coating from the tank as I could get out of it. This is the difficult part. The instructions are explicit that the coating must not be allowed to make puddles in the tank.

I thought piece of cake, just remove the drain plug and empty all the excess coating. Not so! The threads the drain plug screws into are raised inside the tank, so you can't get everything drained. Eventually I found the best place to drain it out was the opening for the vent tube that goes to the solenoid - very messy, use lots of newspaper. Even then you can't get enough out to prevent puddling. So the next best thing is to keep changing the position of the tank until the coating sets up enough that it doesn't run together into a puddle - not fun.

The downside is that the tank has to sit for 4 days before putting it back into the vehicle and putting gas in it. The upside is that I no longer have any rust plugging the fuel system up and the truck runs much better.

The results of this project convince me that some of the posts here about persistant performance and driveability problems could be caused by rusty gas tanks. Simple and inexpensive diagnosis is to get one of the glass fuel filters and put it between the gas tank and the fuel filter.

A bonus! You have almost a half a quart of the coating left over after draining it from the tank. This stuff is tough as nails. Before starting the project, figure out a use for the left over coating.

HTH

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"No matter where you go, there you are . . .", Buckaroo Bonzai