Repairing an Old Rocking Chair

I don't know if this is what your looking for but I found it by Googling 'Instructions for Weaving a Chair Seat'. There are other various instructions out there to choose from. http://www.ehow.com/how_2064761_weave-chair-seat.html
I was given a chair out of my father in law's barn that needed a seat wolven. I bought a roll of SeaGrass and wove the seat and it turned out beautiful! Hard on the hands and a bit of a challenge but what a thrill to see the finished product :) Good Luck and enjoy your heirloom.

If the rungs are sturdy enough, decide which rungs area the best height for the seat.Then just cut a piece of plywood and inch bigger than the rungs on the front and back OR the sides. Cover it with a piece of foam, then a thin piece of batting and finally a piece of upholstery fabric. Staple the fabric on the bottom sides. Once the seat is made set it on the chair, center it the rungs, then from underneath make a mark on the inside of the rungs. Cut two strips of plywood about an inch wide and screw these strips on the line that you made. The seat will be held in place by these strips. Make sure that when you put the strips on that when you put it on the chair it fits snuggly, so it won't slip.