canonicalman

About two years ago one of the cells in the battery exploded showering the surrounding area with acid. The paint peeled off in may places and some rust started. I cleaned this up as much as I could with copious amounts of water and a brush down with baking soda to neutralize any remaining acid.

I recently checked the battery and found the rust had spread like crazy to the point of holes in the bottom and the battery track is almost gone. The negative battery cable was screwed to just a little flange of metal left in the bottom. When I tried to remove the nut, the metal just ripped out. I tranfered the battery cable to the rear tray mounting stud.

The entire design of the battery area seems prone to problems from what I can see. Water runs into this area from the windshield and the drainage is poor due to debris easily building up under the battery tray.

Q. - What can I do now to remedy this situation? Go to a body shop and have them start cutting and welding? For a small fortune?

My own thoughts are to Naval Jelly and wire wheel the rust, hope to get it all, then just give it a coat of paint. Plus a new battery tray.

Tourette(AFC2.812v)

use something called Liquid plastic(rust neutralizer)

Jretal

like you did, to neutralize everything. THen I got a wire brush in there and cleaned all the rusted areas down to the bare metal. From there I applied some of the NAPA rust inhibitor. Another good product is POR15 (i think that's what it's called... a lot of the older Audi guys use it on their cars that weren't galvanized). From there I coated the entire battery area w/ plasticote.

For the surrounding areas that I put it (basically the runoff areas) it has held up really well. As for the battery tray itself, it's held up, but the coating is now peeling off and it's rusting underneath. I will eventually probably make a SS or AL battery tray to stop this... I already had to drill out and replace my hold down bolt w/ a ss one cuz the carbon steel one sheered off in the nut b/c it was so corroded/rusted.

it's a dumb design basically. All the water washes off the windshield and goes right over the top of the battery. So any acid that builds up gets washed off and onto the car where it rusts, so even if your battery doesn't blow up like yours, you still have the same issues... they could have done a lot better design-wise that's for sure.

canonicalman

One other thing I did with a previous car was to build a battery tray/box out of fiberglass. Completely corrosion and water proof. Easy to build too. I would have thought that Audi would have built some kind of plastic battery compartment to begin with. Oh well, out to the garage ...

Jretal

or a flashier version out of carbon fiber... if that's your thing =P

glad i could help.