donovan wrote:in your fifth photo there is a long clip type of thing on the runner. pop the end out that is going into the hole.
then they should come out the rest of the way. hope that helps. (worked for me)
There is a protrusion on that side of the seat base which bumps against that spring to prevent seat moving forward off the rails accidently. DEPRESS this spring into the hole so that the protrusion can slide over the top of it to get the seat completely off the rails.
Maybe rusted a bit by the look of the rest of the floor! Maybe the plastic runners aren't there or have broken up causing seat to lock on runners.
DH