Mike Gholson wrote (to the 240Z list): Okay, I need to remove my battery tray so that I can get in there to treat/remove the surface rust. The tray is tack welded three different places. Who knows the best way to remove this tray?

Pete Paraska replied: The best way is to drill out the spot welds from the engine compartment side. They are fairly easy to see, especially if you remove the paint on the flanges where the welds are. The last place the paint will be is down in the spot welds, making it easier to see. You can just simply drill them with a regular bit, but it is preferable to use a "spot weld drill." It's like a small hole saw. It is guided by a center point that you insert into a center punch mark you make. (I like to use one of those automatic center punches that you just push down on where you want the center punch mark.) You can get the "spot weld drill" or whatever they call it from Eastwood Co. http://www.eastwoodco.com/ or call 1-800-345-1178). They mail out free catalogs every month. For this area you'll probably need a 90 degree attachment or a close quarters drill motor to get a straight shot at some of the welds against the inner fender in front of the battery. You have to have the spot weld drill shank normal (perpendicular all ways) to the surface or it will walk off the spot weld. You set the "spot weld drill" to drill a certain depth with using an allen screw in the tool, so that you only drill through the top piece of metal. After punching and then drilling all the welds with this tool, you remove the part (battery tray).

MG: For the future ... how should I replace it when I'm done getting rid of the rust?

PP: When your done removing the rust and painting underneath, etc., use some Cold galvanizing compound on the mating surfaces (Eastwood sells this also), and weld between up the metal that the spot weld drill removed with a MIG or TIG welder. Grind a little and paint. I've removed a lot of the "two pieces of sheet metal spot welded together here and there" areas of the 240Z like this. Of course, there was little if any paint between them originally, and a very thin galvanizing on the steel from the factory, so there is usually rust found where the two pieces are against each other in between the spot welds. I removed the forward edge of the rear quarters and the spot welds under the bumper indents, most of the rocker panels, the doubler plates for the old style (70-72) front bumper to body attachments, and many other areas with this spot weld drill. Works great on removing that hood latch bracket from the fire wall, if your going the JTR route for the V8 conversion, too. This practice of spot welding several pieces of steel together is fine, but the back in the 70s the factory didn't know much about how to do it so that rust wouldn't form between the welds. I've fixed that with the Cold galvanizing compound on the mating surfaces where I've taken the area apart, and using Zinc Chromate primer where I haven't.