Vintage Cobra Seat Anti-submarine Belt Install
After installing the Cobra seats (that's the name of the company not the car) in the Sunbeam Tiger project I never realized that it didn't have an anti-sub belt slot. What's an anti-sub belt slot? Well it's the place right under your crotch that you pass one or two belts though to typically the floor board of your vehicle. These are typically included on 5 and 6 point harnessed. The purpose of this belt (in my mind) is to do a couple of things, one is to keep you from sliding out of the seat as well as keeping the lap belt at the correct height. No mention of crunching up your privates will be made here. Below is the simple step by step process I used to install the 'grommet' for the porthole for the sub-belt(s).
As with all safety systems please follow the manufacturers directions, and my disclaimer is that I'm NOT AN EXPERT IN THIS AREA SO DO NOT TAKE THIS AS THE PROPER WAY TO DO IT, BUT JUST THE WAY I DID IT TO SHOW AN EXAMPLE. BE SAFE TALK TO THE MANUFACTURER OF YOUR HARNESS IF YOU HAVE ANY QUESTIONS!
Tools and Supplies Needed Sharp Razor Knife
Long Screwdriver or stick
3M Blue Tape (all project will need blue tape if that's not already been said...)
Measuring and Marking Cut out for Anti-Sub Belt
The best way that I could figure this out was to go to a seat that had one and see where it ended up when I sat in it. The hole was a bit in front of my crotch, I measured from the back of the seat so I could duplicate it on the second seat when I get to it.
Bottom of seats webbing
Once you get to the bottom you will see the outline where you poked though. Mark where you need to cut. You may need to put the grommet in the top to get a feel for where it needs to be cut. Try to steer clear of the rubber belts if you can, although on my install I had to cut a tick into them.
Cutting Seat Foam
As you start cutting you might find the foam tearing instead of cutting. If you hold things tight as you cut down through the thick foam it will help. Cut out a full rectangle and then rip it out, as you get lower and lower until you hit the webbing. These seats do not have any metal in the webbing on the bottom of the seat so be careful if yours does and think how the cut will be positioned. If you are thinking that now, you are likely too late.
Cobra Seat Finished Bottom Cut
After a bit more trimming (again leave somewhat smaller then the grommet) here is the final cut. Note I had to cut a tick into the rubber strapping, not enough to worry however.
Installed Top Grommet
Once done wtih the bottom cut carefully install the top part. This will be the smaller sized part, so you won't see the overlap on the 2 parts as it will face down. As you install the grommet through the material it should not be tearing, but should fit snugly stretching the material a bit as it pushes though
Installed Bottom Grommet Half
See, this is why you want the bottom half to be the larger half. You don't want to look at this when viewing the seat from the top. My grommet halves fit tightly and held very well with no pull out. If yours don't, you might try a very little PVC glue on the bottom part were they fit together. Know know that it will permanent at this point. Again, my didn't need anything but a pushing together.
After some lengthy searching for an online source for these seat grommets, I found a place called Sector 111, here is the page link to the Seat Grommets from them. The are not inexpensive, but they had them and they were very good with quick delivery and follow up. Sector 111 Corbeau Seat grommets.
Start Cutting Your Seat!
After you mark the spot where you want, make sure you cut so the vinyl (or leather) will be tight to the smaller section of the grommet. This will ensure a nice fit when all pressed together. Note that the grommet has two different size parts, so one can fit in the other. The smaller will go through the top.