Retrofit shoulder belts in an early 911

[Christien]

It's been an adventure, but it's done. And in the end, it's really not overly complicated. My almost-4 year old daughter uses a booster seat in our minivan, but I've only got an infant seat installed in the Porsche, which means only one kid can ride at a time. So I decided to retrofit a shoulder belt so I can put a booster seat in. Or possibly just have her sit in the already-child-sized reat seat - I have yet to put her in there and see where the shoulder belt sits across her chest, to see if it's safe without the booster seat.

Anyway, I bought a set of 993 seatbelts and proceeded to drill a hole in the metal underneath the parcel shelf. The belt was fully retracted (shipped that way) and was stuck there, completely locked. I couldn't pull it out for the life of me, but that's another story:
993 rear seatbelts

After a part # check I found out they're 993 cabrio belts and must be installed vertically to extend. This was actually a plus, as I was then able to mount them behind the seat back, on the vertical inside of the engine bay. They have to be pretty much within 1 or 2 degrees of true vertical, so I had to makeup up a spacer to attach to the back so the retractor sat vertical, as the vertical part of the parcel shelf is on a slight angle.

My parcel shelf already had aftermarket speakers installed, plus a child seat tether on the other side. I did have to stop and think about putting yet another hole in it, but I've come to the conclusion that when kids are older I'll just replace it with a new one. I figure it couldn't cost more than $400 or $500, so if that's the price of being able to get both kids in there for the next 7 or 8 years, it's worth it.

Basically, you drill a hole straight through the parcel shelf, then through the two layers of the engine bay. Mount a really huge washer (to spread force out), then a lock washer then the nut, then I clamped on some vice grips to hold the nut steady, then tightened it from the inside.

So the retractor mounts outside the vinyl, which is a bit of a bummer (I'd rather it be invisible) but it's not as unsightly as you may think. I did scuff the vinyl a bit, (headliner tear was already there) so I'd advise you be a bit more careful than I was You don't notice it with the seat back up, but still... When the youngest is out of the infant seat, I'll install the other one on that side, and I'm sure it'll be a much easier, faster (and clean) job.

Here are a couple pics (forgot to clean the grease paint off ). It's definitely not an option for a concours car, but for a regular driver like mine, I'm quite happy with it.

[cfries]

Nice write up for an early 911. I know this thread is a few years old but all the research I found was for early to mid 80's 911's. I have a mid year 70's which is very different from the 80's as I do not have the mounting hole in the parcel tray. In fact, my parcel tray seems to be shallow and wont allow a hidden installation like the later years. I think I may have to do what Christien did and mount the retractor on top. Here are some pictures of my 75 US Carrera. My only question is where to drill the hole?





Mock up of retractor on shelf


Side view


Possible cutout on backside of shelf. Its wide enough to pass the seat belt through.