mfidalgo

I recently replaced the OEM battery on my '06 911 Carrera Cabriolet with a Gold-Duralast H8-DLG from AutoZone. The replacement battery is slightly bigger than the original, and requires moving the battery clamp to the outer hole.

The stock battery clamp bolt doesn't fit the outer hole (I think it's too small, as it doesn't catch the thread); any suggestions as to where I can get a bolt that does? I'm told 996s came with bigger batteries and thus getting a 996 bolt might work on the outer hole.

Thanks in advance.

jhbrennan

Interstate makes a direct replacement size for the 997's. The Porsche 996 and 997 batteries are the same part number as are the hold down clamp and bolt. I don't think the outer hole pn the tray is made to accept a bolt.

997sRider

I had the same problem, I just took the bolt to home depot and found a matching nut. Worked great.

mfidalgo

I'm pretty sure the tray is made to take different battery sizes. See, for example:

http://asiliconvalleylife.blogspot.c...1-battery.html

This owner of a 996 had the reverse issue, having bought a replacement battery that was smaller than the original.

jhbrennan

OK - but have you clamped yours down yet? Then we'll know for sure.

mfidalgo

In my 997, the battery clamp bolt doesn't 'bite' into the thread in the outer hole. It seems to be a different size, so that it fits well in the inner setting (smaller OEM battery) but not the outer setting (slightly larger aftermarket battery).

jhbrennan

Well it looks like your choices are to either get a correct size battery or do as 997sRider suggested and use a bolt/nut to attach the clamp to the tray. I'm not sure Porsche anticpated larger aftermarket batteries by putting in a outer setting. If so you would have thought the threads would be there for the OEM bolt and clamp. I would clamp it down though - you don't want it coming loose during your spirited drives.

chrisk1200

I Bought an Interstate MTP-H8 yesterday and had this same problem. I ended up putting a nut on the back of the clamp bolt. This isn't easy to do as you have to hold the nut on the underside of the battery tray with some small needle nose plyers. It does hold down well when completed but it was not easy getting the bolt started on that nut. I wonder if the other Interstate batteries such as the 91 are the correct width. The interstae website lists the H8 as the correct battery but it is actually an inch too wide.

Edgy01

If you have a tap and die set tap into that plate so that you don't have to hold a nut down there. This is simple stuff guys.

Macster

When it came time to replace my Boxster's OEM battery the Porsche parts catalog called out a bigger (in cap. and size) battery.

I removed the old battery and dropped the new one in. It was longer but the holddown hole had a threaded insert and the hold down bolt screwed right in.

If there's no threaded insert possibly you can move the one from teh original hole to the new hole or pick up a new threaded insert and install it in the new hole so the hold down has something to screw into.

I would not tap into the metal. I hate opening up new holes, cutting the metal, especially in the battery box area. These areas can be a place for corrosion to start and are very hard to repair once it does get a start.

Find the proper hold down or get the right sized battery.

Sincerely,

Macster.