STALION

Hi guys, has anyone made, or found a more cost effective way to extend the rear seat threads to install a harness? I found bolt adapters with extended threads from corvette mods but $25 per unit plus shipping in Canadian dollars is a bit excessive...any other ideas?

thanks

ErnieN85

davidfarmer

I just hammer out the old bolts, use longer bolts with fender washers from the bottom. They have a small weld you can cut, or just hammer them out. Install bolts from the bottom, or they will drag the ground when loading etc.

STALION

Thanks guys...I guess this is done from underneath the car?

ErnieN85

at least the insertion of the bolts

davidfarmer

STALION

Sweet sauce! Thanks again everyone!!!

c5racr1

I used these

bigmackloud

I have the Marrad ones posted above. Worked nice.

davidfarmer

nothing wrong with spending $50 on those if you prefer.....I've used them with Hardbar kits, but when I'm making my own mounts I prefer using locally sourced graded hardware for about $3

ErnieN85

cheaper and probably safer too

Fulton 1

As others have noted, just pop out the OEM stud and replace with a proper bolt from below.

Here's a good thread on the subject with some pics. I found it helpful, anyway, when installing my Sharkbar down tubes a few years back. As I recall I ended up giving mine a love tap from below with the air chisel and they surrendered pretty quickly.
https://www.corvetteforum.com/forums...d-removal.html

In my case I decided to just reuse the factory nuts so I went with a metric flange head bolt instead of the 3/8" bolt noted in the link. Stock thread is M10x1.50 and you'll want to spec the bolt's grip length for your particular stack-up thickness. Be sure to use minimum Prop Class 10.9 if going metric or Grade 8 if standard and use hardened washers.

R_W

I used a bit of my grassroots brain and then pulled a page from the Porsche handbook and installed these onto the rear bolts with just enough room to tighten the bolts for full thread engagement. They were a PITA to get on, bolted down, and get the harnesses clipped in, but I am very confident that they are secure. NOTE: These only work with the clip in style harnesses. I'm running 6pt clip-in Schroth harnesses.



Purchased here:

https://www.automotion.com/safety-ha...r-porsche.html

I will snap some pics and post them soon of how they are mounted / secured.

STALION

In preparation for this job I ended up buying hardened M12 boots instead of M10. I also bought a 3/8 heavy steel bar for reinforcement from underneath. I assume that I will have to drill the entry hole a little bigger to accommodate the M12 bolt...has anyone gone this route?

YYZ06

Per the thread in Fulton 1's post, I recommend using a jack and deep socket to support the underside of the seat mount bracket (on the exterior of the car) to avoid tearing up the stamping. The welds can be pretty tough and without support it'll bend & tear the stamped metal bracket. I used a cold chisel but an air chisel would be good for breaking the welds once the stud head begins to separate from the stamping.

Bill Dearborn

Make sure you seal where the bolt goes through so you don't get water in the balsa wood floor material.

Bill

R_W

STALION

​​​​​Yes for sure, thanks!