So my goal with this is to address everything I had wondered about before I got my bus, and detail it simply and clearly online (both here and at our website: juanway.org). There will be more at all major stages including installing bunks, benches, basic plumbing, and getting the bus to run on veggie oil. But we're not there yet. This one is about the first major obstacle - removing the seats.
Step 1: What you'll need
You'll need a ratchet (socket wrench) for the nuts inside the bus.
Where the seats were bolted to the side of the bus, we used a 1/2" socket.
Where the seats were bolted in the center (next to the aisle) we used a 7/16" socket.
There were a couple odd bolts which had probably been replaced by a mechanic after the bus was manufactured, so be ready for that.
Underneath the bus, someone should hold the nut in place with a wrench (7/16" in our case).
Many sites recommend an angle grinder, to just pop the bolts off, and as far as I have seen that works, but if you have the man power, the ratchet/wrench combo is pretty easy, and several people can work at once. Also, more people are likely to have those than an angle grinder.
Step 2: Disconnect seats from the walls of bus
While this person is busy doing this, you can get started on the next step.
Step 3: Removing the center bolts
One person needs to be inside the bus, and they will be turning the bolts with a ratchet (3/8" socket for us).
Another person has to go under the bus to hold the nut with a wrench (7/16" for us). You will want a work glove for this part, and I can almost promise you'll come out with cuts on your hand if you don't have one.
Communication is extremely important at this step, so open the bus windows so you can better hear each other. If the person on top is spinning the bolt, the person underneath won't be able to get a grip so it can unscrew. And of course if the two people are working on different bolts, nothing will get done.
An easy way to stay on the same page is to start at one end of the bus, so you both know what bolts you're on. The person on top can spin a bolt a little bit to show the person underneath which bolt they'll be working on. This system worked well for us, and make the process pretty quick.
Lastly, bolts will break. This bus is 18 years old, and the bolts are pretty rusty. They will break, but it usually doesn't matter, as you can still get the seats out. Less work for you!
Step 4: Remove the Seats
Caulk the empty holes so nothing crawls up into your bus and makes a home.
Then you're ready to make the floor plan and start construction.
We've got a video in the next step if you want to see it.