Patty,
I purchased the mount from
www.mobilelaptopmount.com. Click on the site and peruse through the pics of multiple installations. It is quite informational and entertaining. (I found the site through an earlier thread about 2 years ago). I bolted the flange to the passenger seat left front bracket. Basically I removed one bolt, set the flange in place, and put the bolt through the flange and tightened through the bracket. Requires no drilling into the floor which was a plus. It was such a nice tight fit that I never had to install a 2nd bolt which I had initially planned to do. (It doesn't move one iota!). The pipe assembly is as follows from floor to plex top; 1/2" flange, 11/2" nipple, 45 lbow, 6" pipe, 45 lbow, 3" pipe, 45 lbow, 10" pipe, 45" elbow, and 1" nipple that the plex/flange spins onto. The pipe is all 1/2" standard plumbing pipe. I had to swap out a couple extra pipe lengths/lbows to get the proper plex plate location. Needed only 1 trip to ACE hardware! (On any project like this, normally it requires at least 3 trips to be successful - lol). I also used the teflon tape on the fittings that allows for easy minor adjustments to get the laptop exactly where you want it. Also, mounting off the seat bracket, requires the passenger seat to be in the full back position. (Marilyn doesn't mind at all). Sometimes there is minor laptop bounce (especially on I-10 in MS & LA), but this is due only to the length (heighth) of pipe used. The bounce has never been a problem. The bottom flange remains rock solid tight as do all of the fittings. Hope this helps.
Jim