Just for lazy people like EO2K - What do you do when a foamectomay just won't cut it?
I picked up a new to me Hard Dog roll bar last weekend. Install was quick and easy, but I ran into a nasty issue with seat height and driving position.
At 5' 10" I was bumping my head on the roll bar. Since I'm hunched over to see stop lights anyway, I decided it was time to lower my seating position. After some trial and error (including sitting ON the floor) I decided that 2" lower was a good target.
From reading about foamectomies, I know we're not going to get a real 2" drop and retain a comfortable DD seat. My first pass was a "bottom" foamectomy cutting out the bottom bump on the NB seat. The foamectomy got me about 5/8". While not bad I'm still bumping the roll bar.
Time for drastic measures. We pulled the seat out, shortened the bottom bracket of both sliders, removed both of the "humps" that the stock sliders mount to and bolted the shortened (steeper rake on the seat) slider rails directly to the floor. We back plated both of them to reinforce the floor since the "humps" were pretty stout. Since I had already done a foamectomy I was able to hammer the bump in the seat pan up about 1/2" to clear the carpet.
All in all, a pretty dramatic difference and I retained the ability to adjust the seat. It took the better part of a 8 hours, but that was a lot of engineering and trial fitting.
I'm pleased with the results (both seats in the same position on rails and same recline angle):
How To (Proceed at your own risk!)
First we removed the seat.
Next we removed the slider brackets from the seat (4 bolts on the tracks, 2 on the tranny tunnel side and the main seat belt receiver bolt).
With the slider brackets free we also disconnected the wire connecting the track adjustment mechanisms (Green arrow).
The picture below is the driver side, outside bracket and is the easiest to start with. We ground off the rivets at the back (Red arrows) and removed the stamped steel bracket (red circle). This frame rail is now modified. The new bolts go right through the holes left by the rivets, through the floor sheet metal, through the backer plate and get nuts (with lock-tight). You may want to enlarge the holes a bit to use a bigger bolt, but don't go much bigger. Also a bolt with the shoulder ground down makes install easier since you can slip it into the channel of the seat rail and it won't spin while you put the nuts on from the bottom.
Now, the tranny tunnel side rail is a bit more complicated. The front and back mounting points are actually a single piece of stamped steel. The basic idea is the same, locate and grind off the rivets that hold the back of the rail the seat slides on to the mounting bracket (Circled below), then make a cut at the red line (it's a U shaped channel so it's really 3 cuts). The goal is to cut the bottom piece that bolts to the stock mounting hole off, while leaving the actual slider rail intact. Just like the outside rail, we'll use the rivet holes in the slider track as our new mounting point.
Installed in the car, the picture below is looking in from the driver's door, the tranny tunnel in the background. The outline in red is the stock bracket that we removed (dad's fingers are touching it in the picture above), the green marks are the approximate location on the rivet holes.
After drilling holes through the floor and building backer plates, reattach the rails to the seat pan. There are now 6 bolt holes instead of 4 (Red arrows). In this picture, the seat is propped up upside down and the far side is the tranny tunnel side. You can see both of the front mounts remain stock.
We also used a dead blow hammer to cave in the lowest part of the seat pan. The bump we removed foam from during the foamectomy actually drags on the floor if you don't modify it. Don't go any farther than you need to (~3/4" at the back) or you risk compromising the rigidity of the seat pan (and the back of the seat).
Let me know if this still isn't clear and I'll take some better pictures next weekend when the seat's back out.
Oh and I almost forgot, the humps:
**Make sure to protect the interior and soft top. You don't want hot metal shavings on that stuff!**