I found this thread while trying to put an eighth seat in my 2019 suburban premier. I have the mahogany/black interior so the middle seat in black was a pretty good option considering the mahogany color or the premier never has the eighth seat option.
the center seat is out of a 2019/2020 Silverado or Sierra. The seat itself is vinyl and firm. It doesn’t quite match the leather but it’s close and it’s the kids favorite seat. It sits up a little higher and forward so the rear seats can still fold. The built in seatbelt is what made this one the best option for me.
I used stock parts with little to no modifications so the average person can do this.
sparco 00492lat adjustable seat bracket $99 worked well. Mine is installed as low as possible in the rear and high in the front to match the stock recline angle. If you want your seat lower, the you would have to cut the top of the bracket and drill a new hole for the rear
sparco seat bottom hardware.
Seat with belt installed. Mine does not have storage bins or power or vents. $225 from ebay.
Grade 10.8 bolts and nuts and lots of washers from Lowe’s. They need to be the ones with thread all the way to the head so you can tighten the first nut right to the oem seat brackets. I got an assortment of lengths so I didn’t have to cut any and they don’t poke up through the carpet. They were the largest metric diameter that fits the sparco bracket. I also doubled the bolts in the rear because of the seatbelt.
First line up the seat so it’s straight. Note that the suburban floor is not symmetrical. The OEM brackets are at different heights in all 4 four corners. I fixed that with extra washer and nuts using 3 different length bolts so they are all the same height at the end and the seat is level.
Mark holes. I used blocks of wood and shims to hold the seat still. Make sure the rear seats fold down if you wish. I had the kids sit in it and make sure it’s where we all wanted it because it will not be easy to move again.
Now unbolt the oem brackets, drill holes and install the bolts, washers and nuts.