With the seat in and everything loose, it gets really difficult to access the bolts. Feel free to give this a shot if you want, but it is very time consuming and you'll just wind up pulling the seat to install it the much easier way I figured out anyways.
There are two ways of going about installing these brackets and I feel I did the wrong way first. This is where the community gets to learn from my mistakes though! With the rails loosely bolted into the car, I loosely bolted up the Flipside Customs’ brackets. At this point I loosely bolted in the seat so I could use the slop in the brackets to position the seat right where I wanted it, which was as close to the center of the car as possible. I started to tighten everything up and ran into the issue of access to bolts being quite difficult. The seat had to come out to tighten everything up and then all of a sudden the four main bolts holding the rails to the car no longer lined up, thus defeating the purpose of the original idea of installing everything loosely in the car in the first place.
After a lot of loosening and tightening and using a pry bar to get the rails to line up, the first seat was in, but I knew there had to be an easier way. What I should have done was to do everything outside of the car, measure the distance of the main four mounting bolts and then just match that to the rails outside of the car. This took a quarter of the time, maybe even less than that and would be the way I recommend installing them for other Lotus seat users. There was one issue that cropped up on the passenger side. The tension spring that locks one of the seat rails into place had pressure on it. This tension kept the spring from working properly and the rail wouldn't lock into place. This could potentially be a big safety issue, because only one side of the rails would lock. This also could be unnoticeable, because the other rail doesn't rely on the same spring and would function normally. There is an easy solution for this problem though and it involves bending the pin that the spring coils around. With the pin bent up for additional clearance, the spring works perfectly and both sides of the rails lock right into place.
Here's how I would recommend installing the brackets to the seat. Upside down and out of the car. The important information to keep in mind is how you'd like to position the seat in the car, as there is adjustment left to right. I pushed both seats towards the centerline of the car and tightened down the rail closest to the centerline of the car first. Then I took measurements of the four main mounting bolt locations and tightened the ouside bracket to match those measurements. Voilà!
The seat belt receiver is mounted directly to the bracket and the OEM Miata bolt threads perfectly into the seat. Our 93 Miata doesn't have seat belts of this design, but we just so happened to have some later model receivers that came with the M Edition seats that were previously in the car. I have read that the early Miata seat belt receivers can be uncomfortable and feel less safe with the Elise seats and the later receivers solve those problems.
This spring is very important and the following information is critical for safety. This spring allows the rail to lock into place. On our installtion, the seat bottom was in contact with the spring, which kept the rail from safely locking. Using a prybar, the pin that the spring sits on was bent upwards, taking the spring out of contact from the seat bottom and allowing it to work as intended. This is something that could be easily overlooked and the seat would still, more or less, work as normal because the lock on the other side isn't affected. In an accident though, one seat rail lock might not be enough to hold you in place. This was only required on the passenger side for our application, so it may or may not be required for other installations, but something to be aware of!
A few close-ups of the mounting of the front bracket to the rail. You can see the added gold colored washers that have additional surface area vs. the original washers provided.
We have a washer on both the top and…