I usually have to drive home to grab another vehicle to make it happen.
My van is a 2007 E250 and I scored a jump seat from a 2011-2016 F250 off eBay for $90.00.
Installed it by drilling holes in the floor and the good part was the bolt holes lined up with my factory panel seams in my floor.
I used angle iron underneath for mounting tabs/strength.
I had to cut my center doghouse console and just keep the top half which can be removed easily when folding the jump seat in the upright position.
I ruined the seat belt latch eyelet when I tried to drill the eyelet hole bigger.
I held it on my drill press with a welding clamp but as soon as the drill bit caught the hole the clamp let loose and the seat belt cable started spinning in the press wildly and beat the buckle latch to smithereens.
Luckily the stars aligned and I robbed a buckle latch from my Honda Odyssey jump seat that I had lying around and it worked perfectly.....even had a larger diameter eyelet hole.
I guess all jump seat buckles are universal because it works perfect.....lucked out.
Anyways the install worked out well.
So anyone wanting to do something similar now you know it can be done.
