It is easy enough to split the back from the base but I'm not sure without looking at it that you wouldn't have to take the seat out anyway to get good access. You need to get something in behind the plastic covers to push the centres out of the three retaining plugs and I think this may be difficult, especially on the inner side where it is next to the tunnel. If you have to take them out anyway, you might as well just change the runners. Cheers David