divil

I've had a small amount of water leaking onto my DME in the last few days, causing some temporary running issues. But, I had my battery tray completely replaced a few years back, and it still looks very solid. There's some minor wear in the paint, but nothing significant. However, I did recently install a WB02, and I made a hole in one of the grommets at the rear of the battery area for the wire. On closer inspection, it looks like I made a much bigger tear than I wanted to.

Does this look like it would explain water getting in? It's too high for water to fill up to there obviously, and it's covered from the top by the plastic cover, but I was thinking water could be splashing up there. There were a few drops on the wires themselves so it must be splashing up there somehow.


The hole is pretty obvious but I circled it here anyway:




The area marked here had a few drops so it seems possible that it could be getting in through that hole...






Does this sound like a plausible theory or should I be looking elsewhere? Also, Is there anything I can do to seal this up? I'm not sure how easy it is to replace the grommet. Is there a way to seal the hole with something?

Charlie

Some black silicone adhesive and sealant should work.

divil

Well it looks like it's not that simple. I removed the glove box and put the car in the rain for a while to see what was going on. After a few minutes I spotted a faint trickle of water going down along the insulation behind the DME bracket. So it looks like it really is leaking somehow. It wasn't coming from the grommet as I suspected. From the top, I could see water pooling in at the firewall end of the battery tray. But the tray looks totally solid. The paint still looks fairly fresh and there's a layer of rubberized coating under that. So I can't figure out how it can be leaking there...but it is. I really hope this is something I can fix easily with some kind of coating. The guy who replaced the tray for me was adamant that it was much better than the factory job and would never leak again.

mel_t_vin

John, while not an expert by any means, my understanding is that three pieces of sheet metal come together [and are welded] in this area...the firewall, the tray, and the forward unibody.

Do you have any photos from the work that was done on your battery tray? From what I've gathered, the end result of this particular job depends on the knowledge and skill of the craftsman [e.g. proper preparation, sealing, welding, and finishing].

divil

I don't have photos, but I did see it with the tray cut out, and again just before painting. It looked perfect tbh.

On closer inspection, the water is dripping down from the altimeter. That appears to be directly below the passenger side of the bracket that holds the battery in place. It looks like this bracket is raised slightly above the floor of the tray, and the gap is sealed on one side but not the other (it's open at the front). Also there's a short space between the end of the bracket and the wall of the tray where water seems to collect. So I'm pretty sure the leak is underneath the bracket. Whether it's a bad weld or a hole has rusted through, I don't know but I'll remove the ABS computer and other things from underneath the tray and have a closer look.

konakat

If you pull everything out and look up from the footwell, it will probably be obvious. Under the bracket is a common spot for rust.

divil

Water gets stuck in the area I marked off in green. That look like a bad thing to me, since the drain hole is on the other side so that water will just sit there until it evaporates. I'm guessing that's why it has started leaking again.

The gap under the bracket is sealed on the side indicated by the blue arrow, but it's open at the other side, so water can collect under the bracket.

But I think the leak might be from the narrow area between the bracket and the fender, just forward of the drain hole. Water seems to sit there after the rain. There's no visible rust but the area is rough - I always assumed that was the finish of the weld but now I don't know.




Here's the gap that the blue arrow points at - looks like he put some kind of filler in there before painting:




And here's the gap under the bracket from the other side - wide open, and it doesn't even look like any paint got in there either.




Should it have been left open completely all along? It seems that might stop water from getting trapped in the front half of the tray.

xsboost90

looks to me like its been repaired- yes i would seal that up

Tom M'Guinn

I suspect this post was superseded by your rust recurrence thread, but for what it's worth, the factory used a lot of seam sealer on the battery tray floor, some of which gets under that battery bracket like in your picture. On my 86, the seam sealer did not fill that void completely, so the water could pass under it. On the spare 87 and 88 battery boxes I picked up to fix my rust, both of them had a lot more seam sealer and that void was entirely blocked off. Whether that was an intentional move by Porsche or some the whim of an assembly line guy, I don't know...