Does anyone know the size of the bolt that connects the seatbelt bucket to the seat? I'm trying to attach it to my sparco seat bases. A m10 1.25 pitch nut fits the threads, but it is super loose and wiggles around until its tight. Its barely smaller than a normal M10.

I guess I could find a normal m10 bolt and stack a few washers to make a spacer for the bucket if I can't find a perfect fit, or use nyloc and threadlocker and hope it stays.

 

Hey I have the same question. I have same seat base (planted brand) and was wondering what bolt size you used?

I want the bolt size to be tight so the seatbelt receptacle does not move around.

 

Hey, if you want it tight, just use a m10 bolt. The oem bolt has a built in spacer to allow the bracket to rotate.

I think it might be a SAE 7/16 bolt, but I haven't tried one yet. Im just using the loose bolt torqued down. On the passenger side, I put a normal m10 nut and bolt. I use seatbelt extenders to loop through the bucket seat, so I don't need the rotating. I'll probably replaced the driverside with that too if I get the chance

 

Hey! The oem bolt has a thread pitch of 7/16 x 20

But that spacer’s diameter (on the oem bolt) is slightly bigger than the threads. Spacer’s diameter is same as the inside diameter of the seatbelt receptacle.

Would you happen to know if the diameter of an M10 bolt is perfect for the diameter of the seatbelt receptacle?

 

Not sure if its perfect, but the m10 bolt I used on the passenger side seems to hold the bracket well enough. I don't know what seat base you have, but I think the one I had a smaller hole than the seatbelt bracket, so m12 might not work. The seatbelt bracket hole is bigger to account for the spacer, so its not going to match up perfectly. I used a flange bolt, so I think a few washers would be your best bet.

 

I’ll go ahead and check it out sometime this week to let you know what I used.

Based off this video starting at 9:30:


you can see that he reversed the OEM bolt and the spacer was a good fit with seat base tab.

which makes me think the seat base tab inside diameter is same diameter as the seatbelt receptacle.

Me and the guy in the video have “planted” seat bases. Same manufacture for sparco seat base!

I just used my calipers and measured the seat base tab diameter. It was roughly 14mm

 

Interesting. I have sparco bases. I just checked and the space on my bolt doesn't go through the hole on the seat base. I would probably just go with the widest bolt that fits in your case.