Rusty Battery Box advice needed

Looking_for_911 · 08-01-2009, 05:27 PM

Hey guys.
The first thing I need to address on the 911 is a bit of rusty residue in my battery box. I poked it with a pick and for the most part it is still solid. The PO of the car was using a plastic tray under the battery and this would still work ok but I want to address this area now rather than taking a chance on it getting worse later.
The box is very dry, it doesn't appear as if acid has been on the metal for a long while, and I would like to clean it as best I can, maybe prime it, and in the one or two small places where there appears to be a hole fill that some how.
I plan on continuing to use the plastic tray as well as a battery tie-down somehow.
I'm attaching a photo, so if y'all would look it over and give me your suggestions I'd appreciate it. Top left and bottom right are worst areas.
Thanks!

DRACO A5OG · DRACO A5OG's Garage

I sprayed some rust killer paint from Rustoleum.

kidrock · 08-01-2009, 05:44 PM

as long as it's still solid, I'd clean everything spic-n-span and then POR15 the heck out of it.

WilsonTC · 08-01-2009, 05:45 PM

Wire wheel to bare metal. Prep/prime with POR-15, then paint to your desire (or leave the POR-15 finish...no one but you will ever see it). Your battery tie-down consists of the metal lip toward the back and another clamp in the bolt-hole toward the front.

RSTarga · 08-01-2009, 05:53 PM

after you do the above switch to a gel type battery unless you want to do this once a year

Looking_for_911 · 08-01-2009, 06:23 PM

The current battery is a NAPA special that the PO installed. The thing has fixtures for two vent tubes on it and I can see where One was attached as part of it is still on the battery. But none run out of the bottom of the fender or wherever it should go to drain.

The overflow most likely came from the battery tender being on too long (my somewhat un-educated guess) or possibly heat and it overflowed into the plastic tray below. Just about 1/2 inch or so but too much acid for me!

I'm assuming POR-15 can be had at any good automotive paint supplier?

Thanks so far, guys.

WilsonTC · 08-01-2009, 06:31 PM

Quote:

Originally Posted by Looking_for_911

I'm assuming POR-15 can be had at any good automotive paint supplier?

Not sure I've ever seen it in a store...always purchased on-line: www.por15.com

Looking_for_911 · 08-02-2009, 11:56 AM

Thanks WilsonTC ... and others!

Scott R · Scott R's Garage

Most of my local auto paint stores sell POR, and for often times less than the shipping costs from POR.

scottb · 08-03-2009, 07:39 AM

+1 on the recommendation for POR-15. If you're going to fill the holes, though, you might check with POR-15 to be sure that the paint will properly bond to whatever you're going to use to fill the holes.

Good luck!

Looking_for_911 · 08-03-2009, 03:54 PM

Quote:

Originally Posted by scottb

+1 on the recommendation for POR-15. If you're going to fill the holes, though, you might check with POR-15 to be sure that the paint will properly bond to whatever you're going to use to fill the holes.

Good luck!

I thought about using the round wire brushes from my rifle cleaning kit to try to clean out the holes where it looks like the bolts for the safety clamps go.... I want them to be rust free as well as I want to use them for the safety clamps.

kidrock · 08-03-2009, 04:06 PM

I would use a brass brush (size of a toothbrush) and scrub the area by hand using a solution of Baking Soda and Hydrogen Peroxide. The solution will neutralize the rust. Use plenty of water-soaked rags to clean the area thoroughly. Then apply the POR-15. If you choose, prime and paint the area afterward.

There are a couple of guys here that have the link to some places with great touch-up colors.

COL 911 · COL 911's Garage

Anyone have photos of how non-gel battery 'should' be properly vented? None of the holes in the area of the battery tray seem to pass all the way through the sheetmetal to the exterior. I currently have medical tubing extending the battery vent tube - to nowhere, just lying loose in the trunk .

Looking_for_911 · 08-03-2009, 04:41 PM

Quote:

Originally Posted by kidrock

I would use a brass brush (size of a toothbrush) and scrub the area by hand using a solution of Baking Soda and Hydrogen Peroxide. The solution will neutralize the rust. Use plenty of water-soaked rags to clean the area thoroughly. Then apply the POR-15. If you choose, prime and paint the area afterward.

There are a couple of guys here that have the link to some places with great touch-up colors.

I had thought of using baking soda to neutralize the acid residue but have bought the starter kit of the POR-15 which has two solutions in it and enough paint to more than do the bat. box. After buying the kit I read the instructions, duh, and it mentions washing the soloutions throughly... I may not been too keen on putting that much water in my "trunk." I will have to eyeball it when my chemicals get here.

Looking_for_911 · 08-03-2009, 04:41 PM

Quote:

Originally Posted by COL 911

Anyone have photos of how non-gel battery 'should' be properly vented? None of the holes in the area of the battery tray seem to pass all the way through the sheetmetal to the exterior. I currently have medical tubing extending the battery vent tube - to nowhere, just lying loose in the trunk .

Fine question as I have wondered this myself!!!

kidrock · 08-03-2009, 05:16 PM

Quote:

Originally Posted by Looking_for_911

... I may not been too keen on putting that much water in my "trunk." I will have to eyeball it when my chemicals get here.

That is why I suggested using water-soaked rags for cleanup. This ain't no Ford, where you can just grab a hose and go crazy. It'll take a little finesse.

As far as the gel batteries go, here's my opinion...please note that this is ONLY an opinion. The subject of gel batteries (Odyssey) versus good ol' Interstate batteries will stir up the same amount of venom as the "Bra vs. No Bra" debate.

I used Odyssey gel batteries for years in my custom Harley applications. They are very expensive and can be a pain in the a$$. They tend to crap out quickly, if frequently allowed to drain...leading to the subsequent recharge. They just can't take that kind of abuse very long. Yes, they are lighter. Yes, they are cleaner. But they are kind of "maintenance-intensive", unless your electrical system is completely (and I mean COMPLETELY) trouble-free.

And although I'm no expert with Porsches, I can safely say that very few of these cars fall under that catagory.

Just my .02 cents.

Looking_for_911 · 08-03-2009, 05:59 PM

I appreciate your "two cents."

500_19B · 08-04-2009, 08:26 AM

I would suggest cutting a few "inspection" holes and looking in the void between the suspension pan and fuel tank support.

Quite often, if battery acid spills are not well-cleaned, residual acid stays in this void and causes a lot more corrosion than may be apparent. I had similar, perhaps even less, visible rust on my '85, but when I dug deeper I found it was much more than I expected. And this was a car from a good climate with a spotless body otherwise. You can see my story here:

http://forums.rennlist.com/rennforums/911-forum/499091-battery-area-surprise.html

However, you may be more fortunate (and I hope you are), but it is better to open in up a bit and really know what you are up against first. Best case you just weld the access holes back up - you have to do paint work there anyway.

Another clue may be visible when you look underneath the car. The bottom of the suspension pan under the fuel tank support has three, soft rubber plugs covering drain holes. If you see an orange-ish hue around these plugs, that is a definite sign of corrosion going on inside.

Good luck!

Looking_for_911 · 08-04-2009, 08:29 AM

Got to the battery box for a little while this morning and the job that I was sort of dreading isn't going to be so bad afterall. The photo actually makes it look worse than it is. The rusty color is so very light that a few passes with the little wire brush had it gone. I plan to take my drill with wire brush attached to finish removing all of the original coating as I am leary of some corrosion hiding under there. All in all it is going to be a Very light job with Very minimal metal damage....except for the top left in the photo where the open place is in the metal... I was wondering if I should JB weld that gap together or just be sure to get the POR-15 on there good?
Any opinions?

Looking_for_911 · 08-04-2009, 08:31 AM

Quote:

Originally Posted by amjf088

I would suggest cutting a few "inspection" holes and looking in the void between the suspension pan and fuel tank support.

Quite often, if battery acid spills are not well-cleaned, residual acid stays in this void and causes a lot more corrosion than may be apparent. I had similar, perhaps even less, visible rust on my '85, but when I dug deeper I found it was much more than I expected. And this was a car from a good climate with a spotless body otherwise. You can see my story here:

http://forums.rennlist.com/rennforums/911-forum/499091-battery-area-surprise.html

However, you may be more fortunate (and I hope you are), but it is better to open in up a bit and really know what you are up against first. Best case you just weld the access holes back up - you have to do paint work there anyway.

Another clue may be visible when you look underneath the car. The bottom of the suspension pan under the fuel tank support has three, soft rubber plugs covering drain holes. If you see an orange-ish hue around these plugs, that is a definite sign of corrosion going on inside.

Good luck!

That's good advise.... I just saw this post after I posted the one above... I'll check this out!
Thanks!
--J