Sorry Ernest (and everyone reading this thread)... I was apparently vague:

My '88 seat belt anchor plate hole has a diameter that coincides with the shoulder diameter of the bolt. Whereas the '91 anchor plate hole has a larger diameter that coincides with the post on the seat frame.

Therefore, it is not a bolt issue, rather an anchor plate issue. My '88 anchor plate isn't big enough to slip over the '91 post... only the is really holding it in place. The bolt head and lip of the post hole are the only side-to-side limits. Very spurious arrangement.

When I locate the correct diameter anchor plate -I will have the correct bolt for it.

 

Barry,
"LIGHT BULB!!!" (maybe... hopefully) I've seen that the new version of PET(7) actually filters by VIN through the internet. If you can find someone who's using it, maybe they'll be able to run your VIN and see exactly what works and what doesn't (rather than trying to decipher the serial number). I haven't seen or used PET7 but I read somewhere that the filtering by VIN through the internet is a new feature.

Also, if anyone reading this is using PET7. How do you go about obtaining the licensed version with full functionality? And, do you think what I'm suggesting will actually help?

We'll solve this sooner or later

 

Thanks for the thought Evan... but in this case, my VIN has nothing to do with it. I am replacing the '88 seats with '91 seats, and I don't have the VIN of the '91 donor car.

Since I haven't used Mason's drill method to remove my broken passenger seat, I still have the new seat in the garage along with my original driver seat.

So, I took some pics to further illustrate what I am referring to...

If I have to drill out the hole in the anchor plate to the larger size I will... but I would prefer not to compromise the strength of the metal.

 

So 88 and before uses the whole bolt for load. Load at shoulder of bolt.
The 91 uses post to take load to the bolt.

Maybe the simple bolt in the latter design is cheaper than the shoulder bolt in bulk?

 

...So doesn't the threaded post of the '91 just replace, and improve the strength of the anchor with the bolt? When the buckle is secured to the anchor, you need one that's diameter will fit over the new threaded post from the '91 seat? Or does it already sit that far our on the '88?

Is your serial number on the '88, 60001 - 65000? The 40001 - 45000 is a '88 Euro
964 803 183 01 is the buckle used in a 88 (USA, CAN) and not used until serial number 41284 in the Euro. The sport seats for an '88 would end with 04 instead of 01. Now, since PET also includes the letter (K) in the 92KS841284, and the letter to represent a '90 is L , and a '91 M, then M which is the first digit that is uncommon in this series of numbers (when comparing a 88 and 91 abbreviated vins used in PET) Then M is greater than K and any serial number with a K. So 964 803 183 01 should work on a '88 to '91. I'd have to look into the buckle for later years to say if it works for them or not. That just took me an hour to write... my brain hurts. 964 803 183 01 is the buckle you need to secure to the '91 seat anchor, properly. I really hope that made sense and is right.... what do you think?

 

Not sure if it was a cost factor vs. a safety factor, Ernest.

On the '88, the shoulder of the bolt bears the entire force of an accident against it. Whereas the '91, the post on the seat frame plus the bolt threaded into it bears this force... essentially doubling the strength of the anchor point.

As shown in the latest pics, I have the bolts. I can get the assorted washers I seem to be missing... but I need to find the larger diameter seatbelt anchors.

Request for all parts sellers: PLEASE leave the seatbelt (latch end) attached to whatever seat it came from! As I am finding it nearly impossible to identify by part number, the item I need... I will probably have to modify the existing parts and potentially make them unsafe.

 

Go here.... http://www.porsche.com/usa/accessori...artscatalogue/

Download the 928 87-91 catalogue and reference the V-Pages and Seat Belt The buckle is #10 in the illustration, you will see the different numbers for the buckle and the Abbreviated VIN for the designated Part #.

 

:typ ing:.......:ty ping:

 

Evan, that would make sense that the '91 post would be the same diameter as the '88 bolt shoulder... but its not. The '91 post is a larger diameter, thus my anchor will not slide over it. As it is right now to drive the car... it is precariously sitting out on an unshouldered bolt. The '88 was flush to the frame and riding on the bolt shoulder.

Yes, my '88 is in that serial number range... however, I do not know the VIN of the parts donor car. It was one of Russell Johnson's cars he parted in late '07. I don't know if it was a Euro or not... the fenders were gone already & it sustained a hard hit in the driver's quarter & rear.

If I had calipers, I would tell you the size difference... the '91 post can't be more than a couple of millimeters larger than my '88 anchor hole.

Clearly, it seems as Porsche made a production modification but did not assign a new part number! (Unless the '91 seat is a Euro or a remanned sport seat)

 

They are the same parts pages as I attached to a post earlier in this thread...

 

...You might be on to something there.

And, sorry I posted that link again. Didn't realize... too focused

 

It's friday night... I'm done with this for now! But, check out the seats catalogue. There's a more detailed illustration of the complete bottom of the seat. If you can find what the anchor is attached to (or the anchor itself) and see if there's a different part #, that would be what you need.

 

God, I hope not... it's hard enough to find sports seats or Euro parts that are otherwise common...


Evan... I keep looking at the pics, my diagram & the PET pages and I just don't get it. Why would Porsche redesign a part, but not give it a new part number? There is no way in hell a Porsche engineer would think a threaded bolt could take the shear force against it in an accident -over a shouldered bolt? The anchor for the '91 must fit over the post to do any good -and thus be an improvement from the '88s shouldered bolt! Therefore, the anchor end of the seatbelt must be different.

.

 

Okay Evan... I found a breakdown of MY codes and VIN serial ranges in the V Pages...

Remember F 92KS8 41284>> was listed as the 'replacement part #' for the buckle end?

It appears the "K" stands for 1989 and that serial number is in the range of production of the '89 928GT. So, the '89 S4s, CSs, and GTs before #41284... apparently had the same setup as on my '88. From #41284 on... it was different. (See pic)

Now, we are getting somewhere!

 

I think you are right!

964.803.183.01 ... that number is for the driver's side.
964.803.183.00 ... is for the passenger side.

999.028.014.02 ...are the replacement spring washers (4 needed)
N.011.655.2 ...are the replacement flat washers (4 needed)

Now, if Mason has any of these items... we may have this thing solved!

Thanks Evan!