Hi folks,

I’m writing about a small technical difficulty when I swapped out my 993 seats for 928 seats (same frame). I reused my 993 seat belt buckles.

The 993 seat belt buckle points are a little different that the 928 belt buckle anchor points. The best description I can come up with is that the 993 seats are an “outie-belly-button” and the 928 seats are an “innie-belly-button”. Therefore, the threads on the 993 seat engage earlier and the thread on the 928 engage a little later. It is for that reason I need a slightly longer seat belt anchor bolt. The 993 bolt works but not enough threads engage for my liking — and this is a critical safety part.

This issue is made more complex by the fact that the bolts need to have a shallow head in order to prevent interference with the transmission tunnel. I tried a regular sized head bolt and couldn’t get the seats square to the mounting holds to mount — it is that tight.

Would anyone know of a solution / how I can get a slightly longer shallow-head mounting bolt?

Thanks

 

So you need shorter bolt for the tunnel side, correct? Rennline includes some bolts with their harness mount anchors. If you tell me what length you are looking for I can see if any extras that I have might work for you.

 

Thanks for replying!

I need the shaft of the bolt to be a few threads longer (not shorter)
I'm trying to look up the length of the bolt on the Internet right now (as I am in Asia for work currently and cannot measure the bolt at home) but it needs to be a few mm longer than what I have illustrated below in green, which is about stock size. The important part is the the head needs to be thin to clear the transmission tunnel.


In the picture below, these depict bolt lengths that are more than enough.



Thank you thank you!

 

OK I got some info.

The stock bolts are Part number 959 803 701 00 (cool, 959 part number) with 7/16 UNF thread. The bolt length is either 30mm (or maybe 25mm).

So anything with 30mm or 35mm --- I'd be much obliged.

Thanks again.

 

Jlaa- I'm going through this exact issue. I have a pair of late 944 sport seats that I'm putting into my 964. Unfortunately, the bolt isn't the only trick. The 964/993 seat belt receivers use a 17mm hole where they fit over the "outie" on the stock seats. The 928/944 receivers have a 14mm hole and use a shouldered bolt with a 14mm shoulder. I ended up buying some 944/928 receivers on ebay. These are the parts that you need to make it all work-

928.803.183.13 driver side seat belt receiver
928.803.183.12 passenger side seat belt receiver
914.803.468.10 bolts x2, 25mm long, 7/17x20 thread, 14mm OD x 7mm long shoulder, 13mm length of thread
911.803.533.00 cup spring x4
911.803.531.00 paper washer x2

All pretty cheap through Sonnen. Here is a photo of the bolt, which will make more sense-

The bolt has a normal head, not like the stock bolt. However, I don't think it will interfere with the tunnel as the pivot on the receiver sticks out further than the bolt.

If you want to use your 964/993 receivers, then you can use any 7/16-20 grade 8.8 bolt that is 25-35mm long. Plus a steel spacer/sleeve that is 7/16ID x 17mmOD x 7mm. In other words, you'll need to make some friends who have a lathe.

Good luck!

 

oh my, this is gold Nick. I'll look into this straight away. I'm amazed someone has run into this exact issue. Power of Rennlist as all.

Thank you.

 

Hi Nick, I got all the parts in red ordered, but the buckles I do not have ordered.

On eBay I see the .12 and the .13 together
I (never) see the .10 and the .12 together.

I always seen the .12 and the .13 together like below ---
http://www.ebay.com/itm/Porsche-911-...9UXlGA&vxp=mtr

Cloud there been have been a transposing of the part numbers above?
Thanks.

 

Well, for internet advice it wasn't too bad You're correct, the .12 and .13 receivers are what you want.

editing original post...

For a price check, I just picked up a nice pair of the receivers on ebay for $35 shipped

 

Seems like you know what you need.

So the bolts I have are for attaching seat belt to the body of the car by the door.
Here is the pic:

 

Thanks so much for all the information. I'm seeing this are asking at around $80 a pair shipped on eBay, so I'll have to do some digging and ask Jeff @ PartsHeaven as well.

Do you have any pictures of how you assembled the setup --- the paper washers, cup spring, etc... all mounts on the belly-button-innie?

I'd love to see your points in action about the 14mm hole and where the pivot lies in relation to the point of most-probable-contact with the trans tunnel.

In true jlaa-form, this means, as always, every job I do takes 10x longer than normal because I'm doing everything three or four times. (pull seat out, put seat in, pull seat put, installer buckle cover, put seat in, pull seat out, redo buckle mounting HW, put seat in, etc etc etc.) :-)

 

With a washer:

 

Seems to me you could grind down the bolt heads as all the force in use is shear and the head takes little stress.

 

I'll try it! I first re-invest in my massively depleted stock on dremel grindstone bits. :-) I used up the last up my grindstone bits grinding down the drag-link socket tool to make it fit the fastener that's used to secure the folding rear seat back to the body. Which I ran around town trying to find --- only to realize no one knows what a "drag link socket" is. Only Amazon knows what it is. :-)

 

Hi Nick, would you happen to know the order that the cup springs and paper washer goes?

The paper washer is elusive --- apparently no dealers (including Sonnen) have this washer available.

Thanks.

 

Hi Jlaa,
I got around to finishing up this project over the weekend. Not at all straight-forward! Honestly, machining a washer/spacer with your original belts is likely the best combination. I hope that I didn't lead you astray. I'll put everything out that I discovered for posterity-

First, Porsche made an absurd number of different seat belt receivers:

964.803.183.00 passenger 964/993, 17mm bolt hole, 21cm long
964.803.183.01 driver 964/993, 17mm bolt hole, 21cm long

964.803.183.04 passenger 964/993 sport seat
964.803.183.05 driver 964/993 sport seat

928.803.183.08 passenger 85-89 911, 14mm bolt hole, 19cm long
928.803.183.09 driver 85-89 911, 14mm bolt hole, 19cm long

928.803.183.10 passenger 85- 944 sport seat, 14mm bolt hole, 24cm long
928.803.183.11 driver 85- 944 sport seat, 14mm bolt hole, 24cm long

928.803.183.12 passenger 85- 944 comfort seat
928.803.183.13 driver 85- 944 comfort seat

Among other versions. I have the 01/02, 08/09, and 10/11 sets. I ended up using the 10/11 set. I'm guessing that the sport seat versions are slightly longer to help clear the bottom bolster.

The mounting for the 14mm bolt hole sets is: seat->paper washer->spring washer->receiver->spring washer->shoulder bolt. I believe that the paper washer is only to tighten up the receiver so that it doesn't flop around. However, with this combo, the bolt head does interfere with the tunnel. I cut out a line of the soundproofing beneath the carpet, about 6"x2", where the bolt interfered. I can confirm that both seats slide smoothly after the trim.

Interesting part is that I've been using a 12-way driver seat and the 964 style seat belt receiver/bolt combo had been interfering on the tunnel with that setup too. No downside to trimming the soundproofing.