Hi everyone! I recently acquired a late 72 914 and I decided to install retractable inertia reel seat belts since I have already removed most of the interior to fix other issues.

I got these 914 seat belts from Seatbelt Planet but I have an unexpected fit issue. The adapter plates, which I think are used for taking shear loads, don't seem to fit properly.

The plates are circled in red:
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The basic problem seems to be that the plates extend below the actual retractor and they interfere with the radius below the mounting hole. The radius is circled in red (not my car...I forgot to take pictures this weekend...):
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This means the plates don't sit flush with the firewall keeping the mounting bolt from going in square. I went through a bunch of old seat belt threads and these are the most recommended aftermarket seat belts and no on else seems to have this problem. Is this a known issue with '72s? I'm thinking about just removing an 1/8" off the bottom of the adapter plates but I would prefer not to if there is a better solution.

I was thinking about putting these very belts in my car as well.

Not really sure what the plates are?
I'm surprised the belts need these plates as they supposed to be manufactured specifically for a 914.

Did you call Seat Belt Planet? What was their response?

Hey that's my picture! I recognize my dad's garage from way back when (2002?2003?) lol

Anyway, I would use a bolt and nut to secure the adapter to the belt body outside of the car in the correct position it will sit when installed. Scribe a line on the adapter plate for the 'extra' material and then disassemble and cut the adapter plate along the scribe/sharpie line.

Then your adapter matches the belt body.

I called Seatbelt Planet and they said the plate is to make sure the the retractor gets installed vertically and isn't necessary as long as I manually make sure the retractor goes in vertically. I don't know if I fully trust the response. I'm fairly convinced that the plates would be useful in a side impact or roll over scenario.




Thanks for the advice. My solution will likely be to cut an 1/8" to a 1/4" off the end of the plate to get a proper fit. I figure that leaving more material can't hurt. I'll post updated pictures once I have made the modification.

Keep in mind those are made for 1973+ vehicles.

The early years did not have retractable belts and I think the body is a little different in later years to accept the "retractor".

From Seatbelt planet: Modern End Release style for 1973-76 Porsche 914 -

I have an early 1972 and will be watching this thread as I don't want to put in 45 year old belts.

Good luck!

My 72 has provisions for retractable belts, but confirm your car looks exactly like the one pictured above. If there's any differences post a picture of what you see and we can tell you.

I recently installed custom aftermarket retractable belts by Seatbelts Plus and used a large washer such as displayed here.

Seatbelts Plus

so the seat belt reels are mounted behind the back pad? Man mine are mounted to the laterals inside next to the seat. I'm a thinking' they is in da wrong place and not original...

Absolutely, but if they work OK....no problem.

yeah I guess you're right. I got plenty of other stuff to do...LOL.

Those were sold by AA (and possibly others) as an easy way to retrofit retractable belts onto the 70-71 cars. Those needed modifications to the firewall to fit the later-style belts.

--DD

My '72 was delivered with the non-retracting belts (which I like) but will look at the body when I can. It is up on the lift, under a car cover, with the backpad installed so it not a quick peek. Hopefully my body has provisions for retracts so I can buy brand new belts.

Just look in the engine bay in front of the relay board and battery. If there's a nut welded there it's retractible

I believe the late 72s have the provisions but the retractable belts weren't installed. The bolt hole was filled with RTV at the factory but it's easy enough to get off.

I finally got a chance to work on the car again and I took some pictures of the problem.

The mounting points for the retractable seat belts are a hole for a pin and a threaded hole for a screw. I've read that the threads are actually for an 11 mm screw (which seems weird since that's not a standard size) but a 7/16 is close enough that they are interchangeable.
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The seat belts I bought come with plates which are too long to fit on this car. You can see a gap between the firewall and the plate because the plate bottoms out on the rounded portion of the firewall.
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After talking to seatbelt planet and the folks here, I have decided to trim the plates to match the seat belt retractor. I'm hoping to get the plates cut and ready to go this week. I'll post before, after and installed pics whenever I finish.

Thanks for following up! These sorts of things often are left undocumented after the owner finds the problem.

If SeatBeltPlanet cares, they might appreciate the info to solve their fitment issue. The issue you ran into would be true for any 914 72-76.

I had no issues installing the Seat Belt Planet belts in my '74. Most time consuming part was removing the backpad.

I believe that the threads for the seatbelts are all inch sizes, likely due to US safety laws.

--DD

When I spoke to them, they said that Porsches from that era have a lot of unit to unit variation. Seems iffy but I don't know enough to really argue against it.


Thanks for the info. That's good to know.


I placed the plate on the retractor and, as suggested here, marked the bottom with a permanent marker. I don't have access to a decent bandsaw or a conventional mill so I ended up using a bench grinder. It took about 5 minutes to do each one.
Here is what the plates looked like after grinding. You can still see the marking on the edges because I didn't bother rounding off the corners to match the retractor profile.
Click to view attachment

It now sits flush with the firewall and I was able to get the belts installed.
Click to view attachment

Thanks for the update!

I just installed these last night on my 75'. Was debating the need for the plate but upon further inspection you will note that the two raised tabs on the plate mate to the back of the unit and stop it from rotating. I had to massage one plate as well but think they are much more stable installed with them. Now I have to figure out a solution for the receivers as the ones from Seatbelt Planet interfere with my Renegade seat side bolsters.

Looks great. Nice work.

I wouldn't install these without the plate for that reason. Bolts are not meant to take large shear loads because there is always gap between the head and the engaged threads.



If you pushed sideways on the bottom plate in that diagram, you would cause the bolt to experience shear and also bending. The tabs on the seat belt plate should help take that load.

As I said earlier in this thread, the person I talked to at seatbelt planet said the tabs were just for alignment and I didn't really need the plate so I would take what I am saying with a grain of salt. However, when it comes to safety equipment, why take the chance?


Thanks. I wish I had more time to work on the car but I really only get weekends!

That plate backs up the already pretty beefy seat belt mount in the car. It can't hurt to have more security there.

Funny, if the threads are SAE, the heads of the bolts are all 17mm. (?)