u/Separate-Bid-828

Like the title says X axis is binding on a 2023 k1, graphite bushings have been replaces x rods are straight, I have checked the machine and it is square. The belt tension adjustment doesn't seem to make any difference is there anything else I should check for? I'm considering the D3D rails upgrade if I'm going to have to take the whole gantry out anyways does anyone who has done the rail upgrade have any thoughts, was it worth it?

Edit: Solved heat-sert for the mystery screw had fallen out of tensioner on left hand side and has been rubbing against the belt and idler pulley surprised this wasn't making a ton of noise.