Battery tray rust and firewall question

[Dershum]

Morning folks,

I'm trying to decide how to move forward on some battery tray rust repairs, and I was hoping for some feedback from those who have gone through this before. First, the pics:

Of course the, first (and biggest) question is "do I need to cut it out". I'm not a rust expert, but I'm inclined to go with "yes, cut it out". If I'm going to go ahead and do that, I'd really like to flatten out the bottom of the battery tray area and enlarge it a little so I can bolt in an aluminum battery tray and set the battery down in a little further, but I'm not sure how much space I have available to enlarge the battery tray area. How close to the inner fender and tire is that location, once everything is back together and on the ground? Do I have a lot of room to work with, or is it pretty tight?

And now, on to my second question. When I bought the car, it had dealer-installed AC which was butchered and partially removed, a completely disconnected heater core, and god-knows-what-else done to the wiring harness. Which means I've got a bunch of holes in the firewall (that I assume are stock) that were unused when I disassembled the car that I would really like to know if I can cap off so I don't have to use ugly plugs to cover them. Here's a pic that I've labeled with what I know/think I know, but I was hoping someone could help me "fill in the holes" as it were

Thanks much!

[AZ-240z]

B is for hood release cable

A is for speedometer cable

Heater hose holes - Yes

A/C hose holes - Yes

And, if you as asking the purpose of the hole in your third picture, it appears to be in the firewall on the passenger side and was

probably used for a drain tube from the A/C evaporator mounted under the dash.

What is the vin # of your car. I am guessing it is a late '70 to early '71 series 1 with a vin between 15000 to 20000.

Good luck.

Dan

Edited April 28, 2013 by AZ-240z

[Dershum]

Dan, thanks for the info. The 3rd pic was really more a question about the condition of the rust, and if folks had any opinions on whether it would be a good idea to go ahead and cut it out or not.

And you're right on the year. Build was 4/71, I don't have the VIN memorized tho.

[zKars]

Grind until you have either clean metal or no metal. If you get the rust gone, and still have enough metal to retain strength in that area (a bit of a judgement call), then you don't have to replace it. If what's left is not there, or paper thin, then cut back until you get to "good" metal (again, judgement call.)and weld in new.

Your battery tray area looks better than most. Bet you can grind those spot weld/overlap areas to clean steel and not have to replace much. Maybe a hole or two here and there.

Happy Grinding!

[Dershum]

Well, I went in and drilled out the spot welds and did some cutting, and the metal where the inner fender meets the firewall was mostly OK up until the point they met. The metal underneath was pretty well rusted...to the point I could poke through it with a flat head screwdriver if I poked hard enough. I went ahead and cut a panel of the firewall out, and the battery box area out, and I'm going to start fabbing up some replacements tonight. The firewall panel should be easy enough, but the battery tray area will be interesting to say the least.

This really brings me back to one of my original questions. How much space do I realistically have to work with to enlarge the battery tray area? I'd like to make it large enough to mount a better battery tray/tie down in there (something like the link below) without having to re-skin the inner fender well, and then create a completely separate platform for the battery tray.

Billet Specialties 248910 Billet Specialties Optima Battery Mount

I cut the fender well about 9 1/2 inches out from the firewall, parallel to it. I'd like to basically create a flat space big enough for the battery to sit down in there, and then just come straight up. It's hard to describe in words, but I'm hoping I get the idea across. Does anyone think there will be clearance issues with the tire if I bring the outer edge of that bottom front corner of the battery tray that far forward?

[zKars]

And again my judgement of how much rust there can be in Datsun is totally under estimated. Dang. Nice hole...

Yes, be VERY careful with tire clearance. Lowering the battery has been discussed here, hunt that thread down.

[Dershum]

Well I got the firewall patched, and I'm pretty pleased with the result. I've also got the fully assembled dimensions of that particular battery tie-down from Billet Specialties, so I'm going to make a cardboard box to match those dimensions, then see where that leads me in terms of the fender patch panel.

zKars, I spent about 2 hours searching around and reading various threads trying to find the one you're referring to, but wasn't able to find it. Any thoughts as to the title or some particular search terms that might help me find it?

Thanks!