Seatbelt mounting bracket sill.

[Lotsof 3146 R]

One a fairly rust free car I managed to remove most of the seatbelt mounting plate with a vacuum cleaner. I’m just left with the bolts to remove, and I’m am struggling to find a way to this. Is patience and a hacksaw blade the way to go or has anybody found an easier way.
New stainless steel Plates read to mount.
And if you haven’t replaced your sill seatbelt mounting plates - it’s time to check....just try unbolting the seatbelt - if it turns easily with the sound of powdering rust you know it’s time...

[Sandyman]

Greetings Lotsof, I also had to replace the outside seatbelt mounting brackets. I found that the only way to efficiently remove the bolts and rivets was a cutoff grinding disc on an angle grinder. I also found that the uniqueness of each Europa means that the nuts and mounting holes may not be in the same place.  Where you able to source the specialized bolts that hold the seatbelt? I also found it easier to get the new mounting plate in place by removing the next rearward rivet on the bottom of the rocker panel.

[Lotsof 3146 R]

Thanks for the advice- I did have to google the term “rocker panel”  having only heard of a “rocker cover” before.
Now I know I need a specialised seat belt bolt I’ll start the search

[Sandyman]

Lots of different car terms this side of the pond.

[Brian Robins]

Lotsof, You need a workshop manual and a copy of the Oxford English dictionary before you work on a British classic car.

[andy harwood]

I made some Stainless plates, tack welded stainless nuts to it. Instead of a seat belt mounting nut/bolt, I used a same size stainless nylok nut, and stainless bolt.
I guess in a effort to quieten the car's interior, the rocker panel void had been filled with the expanding foam product. What a thoughtful gesture by a previous owner. What a pain to remove from the gap between body and pan...

[GavinT]

G'day Gents,

Kosher seat belt bolts should be easy enough to find.
Correct me if I'm wrong, but as I understand it, the large flat-ish bolt head is part of the design and intended to work with the seat belt webbing tab.

I don't know about anywhere else but we'd be pinged for using standard bolts in Oz.

Pic from FleaBay:

[4129R]

I don't know about anywhere else but we'd be pinged for using standard bolts in Oz.

That bolt AFAIK is 3/8" UNF.

It must have a shear strength of over 500kN.

My ribs would not stand that, neither would the fibreglass sill plate.

What is the problem downunder with the bolts? Not HT? 

[BDA]

When I built my car, I recognized those bolts as the seat belt bolts but I didn't remember about the spacer you show in your picture. I started using the standard bolts even though the stock belts didn't fit as well on them. More recently I swapped the stock bolts with AN bolts. Everything fits better and the AN bolts are much stronger than the standard ones if for no other reason than they have fewer threads. But Alex brings up a good point. Maybe the design of the standard bolt was on purpose!

[4129R]

"How strong is a 3/8 bolt?
A 3/8-inch bolt of this type is rated to 7,000 pounds in 6,000 psi concrete (basically granite) and 4,000 pounds in 2,000 psi concrete (hard sandstone). This is roughly the breaking strength range of carabiners and much higher than any rope's maximum possible impact force."

[GavinT]

That bolt AFAIK is 3/8" UNF.

It must have a shear strength of over 500kN.

My ribs would not stand that, neither would the fibreglass sill plate.

What is the problem downunder with the bolts? Not HT?

I thought the seat belt bolts were 7/16 UNF? . . could be wrong.
But I agree . . can't see the bolt head getting ripped off.
The powers that be here would likely see the wrong bolts when inspecting for initial registration.

I doubt they're considering the bolt strength. The fact that it's attached to a plastic car probably doesn't cross their mind either. Many of these things just need to be "as per original spec.".
Jurisdictions vary also and it depends on who does the inspection.

[4129R]

3/8" Grade 5 has a tension strength of 9,888 lbs and a shear of 8,280 lbs.

7/16" Grade 5 has a tension strength of 13,338lbs and a shear of 11,270 lbs.

3/8" Grade 8 goes up to 12,360 and 10,050.

7/16" Grade 8 goes up to 16,673 and 13,680.

I hate to think what accident would generate those forces.

[GavinT]

Agree . . I'd be more worried about a side impact.

Plenty of generic anchor plates around, too.
The captive nuts are in place so no welding required.

[4129R]

The bars which connect the top set belt re-tractor to the rear chassis top shocker mount, are held together by 4 x 1/4" bolts.

Each 1/4 bolt grade 2 has a tensile strength of 2350, grade 5, 3800, and grade 8 4750.

I have managed to shear off a few of those 1/4" bolts quite easily, so I would not rate them higher than grade 2.

4 x 2350 = 9400.

It seems these 4 x 1/4" bolts are the weakest link in the seat belt mountings.

I know the centre ones are threaded into a tube welded into the box of the chassis just below the hand brake cable adjuster horseshoe. That is a very strong connection. 

[andy harwood]

Since I'm packing up everything to move, just happened to pack the seat belt plate I've not installed. I used a 1/2" bolt. Good to know that whatever befalls me in the Europa, I should still be buckled up...