Tub crossmember replacement and seat belt mount/anchor
Posted: Tue Sep 09, 2025 12:16 pm
Hi all,
I’ve been working away on fitting some new 3-point retractable seatbelts to my 1973 GS and thought I’d share where I’ve got to.
I’ve put the brackets between the outrigger and the underside of the tub so I can mount the retractable mechanism vertically on the floor of the tub. That felt a lot more solid than the tub capping, which didn’t really inspire confidence. I couldn’t track down a proper mil-spec bar, so I had a Series bar modified to give me a higher belt position.
That all seemed fine, but when I moved on to the lower anchor points, things started to go wrong. One of the bolts sheared off, and I discovered it was hiding behind a panel of aluminium riveted to the bulkhead behind the seats. Removing the panel opened a bit of a can of worms!
Looks like a previous owner had struggled with the seatbelt mounts too. They’d put in a steel section over the tub crossmember (or what was left of it), made up a filleted bracket, riveted it to the bulkhead, and welded it onto the outrigger. Once I drilled out the rivets and unbolted everything, the whole plate just came away… and I realised the tub crossmember itself isn’t there anymore. I haven't opened the other side up but I'm pretty sure its the same as its also got a plate over the anchorage on the bulkhead.
So now I think I’m into repairing the front of the tub – crossmember and rear bulkhead included. The outriggers looks fine. I’m still fairly new to this, so I’d love a bit of advice:
When repairing the tub, does any welding come into it, or is it mostly rivets and bolts?
Are replacement sections for the tub crossmember available anywhere? I could probably fab something up, but as the important end of mine is missing, I’m not sure what joins to what.
I’ve read that the seatbelt anchors were originally two brackets that sandwich the aluminium of the tub crossmember. Is that right? And if so, does it not connect to the outrigger at all? That feels like a weak spot to me – how have others solved the lower seatbelt fixing?
Any pointers, photos, or just encouragement would be really appreciated. Never tackled this before, so I expect it’ll be a bit of an adventure!
Cheers,
Chris
I’ve been working away on fitting some new 3-point retractable seatbelts to my 1973 GS and thought I’d share where I’ve got to.
I’ve put the brackets between the outrigger and the underside of the tub so I can mount the retractable mechanism vertically on the floor of the tub. That felt a lot more solid than the tub capping, which didn’t really inspire confidence. I couldn’t track down a proper mil-spec bar, so I had a Series bar modified to give me a higher belt position.
That all seemed fine, but when I moved on to the lower anchor points, things started to go wrong. One of the bolts sheared off, and I discovered it was hiding behind a panel of aluminium riveted to the bulkhead behind the seats. Removing the panel opened a bit of a can of worms!
Looks like a previous owner had struggled with the seatbelt mounts too. They’d put in a steel section over the tub crossmember (or what was left of it), made up a filleted bracket, riveted it to the bulkhead, and welded it onto the outrigger. Once I drilled out the rivets and unbolted everything, the whole plate just came away… and I realised the tub crossmember itself isn’t there anymore. I haven't opened the other side up but I'm pretty sure its the same as its also got a plate over the anchorage on the bulkhead.
So now I think I’m into repairing the front of the tub – crossmember and rear bulkhead included. The outriggers looks fine. I’m still fairly new to this, so I’d love a bit of advice:
When repairing the tub, does any welding come into it, or is it mostly rivets and bolts?
Are replacement sections for the tub crossmember available anywhere? I could probably fab something up, but as the important end of mine is missing, I’m not sure what joins to what.
I’ve read that the seatbelt anchors were originally two brackets that sandwich the aluminium of the tub crossmember. Is that right? And if so, does it not connect to the outrigger at all? That feels like a weak spot to me – how have others solved the lower seatbelt fixing?
Any pointers, photos, or just encouragement would be really appreciated. Never tackled this before, so I expect it’ll be a bit of an adventure!
Cheers,
Chris