Seatbelt installation

[SteinOnkel]

Hey guys,

I've got three-point belts in the front of my '78.

I took them out, cleaned them, lubricated them and painted a few bits here and there. Outside of the car, they work just fine.

Then you install them. What is the point of these giant metal brackets? Is it simply to ensure that the front reel does not do anything at all? So frustrating.

Does anyone have a diagram of what goes where and which bolts need the metal spacers? The dpo tore out a bunch of this stuff and now that the carpet is re-installed, I'm at a bit of a loss as to what goes where and how.

Cheers
Steiny

P.S: Also big thanks to Fiat for using M10 fine thread for the fasteners Almost impossible to find locally.

[18Fiatsandcounting]

Steiny, I'm not picturing in my mind the "giant metal brackets". Can you describe them some more, or point to a picture on the Web?

-Bryan

[SteinOnkel]

Hello,

I'm talking about the friend marked in blue:



This shot is in the corner of the passenger side, behind the front seat.

What the purpose of this bracket is, I cannot say. Currently it prevents the reel from spooling back. And also you have to pull on the belt really hard to get out of the bracket and reel to begin with.

There is a similar, albeit differently shaped one on the driver's side. It is also hindering progress.

Cheers
Steiny

[DieselSpider]

That's probably why they had the three point belts mounted higher up coming through the rear seat back which is the only type the 1975 through 1982 factory shop manual covers.

On that style bolted to the floor you need the bracket to transition from the horizontal pull of the retractor and the vertical routing of the belt. Typically they would be installed so the pull was away from the mounting bolt and not toward it and they would be set so that the guide slot was not below the level of the retractor.

An old stiff belt especially if it has twists set in it like the one in the picture will not pass through them easily and the guide itself needs to be pristinely smooth and clean with no rough or sharp edges where the belt passes through.

[SteinOnkel]

The car has two retractors per belt. One behind the seat, one behind the rear parcel shelf.

Hmm I painted the brackets, I thought they were pretty smooth. I'll file them down some more methinks.

I'm considering binning all this junk and just getting a set of new lap belts. Not like anybody will survive an accident in this car anyways.

[18Fiatsandcounting]

OK, now I'm sorta picturing what you have, and I recall having had one or two spiders that had this "feature". I also recall having had issues with these metal guides, and either I just got rid of them and put in later style belts, or sold the car before that needed to happen.

My thoughts are similar to Diesel's: the mounting angle of these brackets is critical, and the belt must be flexible enough to easily pass through the slot.

-Bryan

[SteinOnkel]

I think this might all become a moot point very soon:

https://tinyurl.com/szzb79j

That + a few vinyl "Fiat" stickers, problem solved.

Cheers
Steiny

[TheBender]

Here are a few pics of my 78. I don’t remember where any spacers go. I did put a safety pin through the driver belt as it didn’t want to work properly, so it stays the length I need. Passenger side worked after working in some lube.

[SteinOnkel]

Yep, that's how I installed them.

Well, shit don't work. I'm going cheapo lap belts, screw it.

[baltobernie]

Sorry I can't help you with three-point belt routing; I hope someone comes to your rescue. I can tell you, though, that all seat belt fasteners use 7/16" x 20, Grade 5 bolts and nuts. Doesn't matter where the car originated.

Correction: Grade 5 or 8

[SteinOnkel]

Sorry I can't help you with three-point belt routing; I hope someone comes to your rescue. I can tell you, though, that all seat belt fasteners use 7/16" x 20, Grade 5 bolts and nuts. Doesn't matter where the car originated.

Hmmm are you sure about that? Mine measure out as M10X1.00, Grade 10.9

[baltobernie]

The bolts you removed may have measured M10 x 1, but the OE bolt was 7/16 x 20. Vehicles manufactured outside the US during the Spiders' lifetime often had a bolt head measuring 17mm, which led many users to believe the entire fastener was of metric dimensions. But AFIK, every car delivered with factory seatbelts uses 7/16 x 20. A PO may have cross-threaded your mounting holes. The M10 is 43 thousandths narrower than the 7/16 bolt, so it would certainly fit the hole, but has about 26 threads per inch vs. 20 of the correct bolt.

Have you removed and measured any of the other seatbelt fasteners?

[RRoller123]

I think that you are right, I seem to remember being surprised to find that the seat belt bolts were ASE, not metric. Likely had something to do with US seat belt regulations??

[SteinOnkel]

The bolts you removed may have measured M10 x 1, but the OE bolt was 7/16 x 20. Vehicles manufactured outside the US during the Spiders' lifetime often had a bolt head measuring 17mm, which led many users to believe the entire fastener was of metric dimensions. But AFIK, every car delivered with factory seatbelts uses 7/16 x 20. A PO may have cross-threaded your mounting holes. The M10 is 43 thousandths narrower than the 7/16 bolt, so it would certainly fit the hole, but has about 26 threads per inch vs. 20 of the correct bolt.

Have you removed and measured any of the other seatbelt fasteners?

When I mean "measured" I don't mean "held a 17mm wrench to it and decided it fits"

I actually took the time to get the calipers and the thread gauge out. Because I wanted to get longer ones for easier installation and needed to know the exact specs.

I was initially confused why some seemed to not be M10. This explains why.

the dpo strikes again...

[baltobernie]

Yeah, those PO's can really throw us curve balls.

I meant no disrespect with my "17mm" remark. It was intended to show the ease of mis-identification.

If you're still considering reverting to lap belts, I've had good luck with the BEAMS Retractable Lap HL14146 with 13" Cable End Release Buckle
Retractor Boot Length = 4 inch, Installation Hardware Kit FHD-1046-1. I was able to find a set with a generic release button. You'll need to re-use and modify your floor brackets ...



... which turn the belt 90° and forward to the driver or passenger. That guide also acts as the anchor point when tension is applied to the belt, so a cosmetic filler alone may not be safe. I welded my slot, then ground the contact area to prevent chafing. Extend the belt and clamp it at the retractor. Bunch up the belt on the opposite side of the slot, and use a wet rag to keep the heat away from the webbing. You could use some JB Weld to smooth the slot radius, as long as the bracket is structurally sound.

Be sure and cut the access slot on the bracket side facing the rear of the car. Incredible forces are placed upon these components in an accident; witness the size of the hardware. The seat belt bolts are larger diameter than the engine mounts!