[Doublediz]

I was in the process of removing the rear seat bottom from my 93 vert and noticed it freely just came out and was not attached at all. Shouldn't there be some sort of retainers for the seat bottom to click back in? Below is a picture with the seat bottom removed.

 

[wbrockstar]

It's been awhile since I've looked at mine,but yeah I believe there is either one or two (one on each side) metal retainers attached to the floor that the seat engages with.To remove the seat bottom,it normally requires you to push the top/front portion of the seat downward while then simultaneously pushing the front of the seat towards the rear of the car to get it to release from those retainers. The seat bottom itself should also have something like a hook of sorts that does the engaging.If your retainers are missing,empty bolt holes will be present on the floorboard where those retainers are normally bolted down.

 

[Braindead]

^^^ I would think… if under my seat looks like that am lag-bolting it down (kidding). Might be retainers under carpet sill not showing? Factory never latched, possible?

 

[ALMOST STK]

Possibly

 

[Cobrajet67]

With my 1991 and 1993 I just had to push back a little and pull up on the front like wbrockstar described.
It looks like your car had a replacement carpet installed and the carpet wasn't slit so that the bar retainers can poke thru or the bars were removed completely. They might be there just under the carpet but I can't really tell from the pic. The seat was held in place by the springy metal seat support on the bars.
I found some videos and there's different style retainers depending on the era of Fox body. The pic ALMOST STK posted is for the 1979-89 cars.
On a 1979-89 the underside of the seat should have a section of the thin round spring support on each side that protrudes down in the middle front of each seating area. Those hook onto the 2 small bottom clamp retainers in the floor.

Here's a video for the older style retainers: Fox body mustang back seat removal - YouTube

The 1990-93 had tubular bars that bolted down on the floor on each side and there were semicircular shapes of the spring support that fit onto the bars.

 

[Doublediz]

I pulled some of the carpet up and nothing is there, no holes either. The bottom of the seat does have the bars on each side though but there is nothing for them to latch into. Guessing they were removed, I did find these on Ebay looks like they might be the right ones

 

[wbrockstar]

Possibly View attachment 789317

Like usual and as always, Almost Stock always has the best diagrams on the site as well as the ever popular mega fastener sticky thread.

 

[Cobrajet67]

Like usual and as always, Almost Stock always has the best diagrams on the site as well as the ever popular mega fastener sticky thread.

Though it was for the older version only up to 1989 it was a nice clear diagram. What is this sticky thread you speak of?