What the heck is the spline size anyways? Will a quarter inch really make a difference?
it is talking about the hole that the arm attaches to. the spline is the knob or axle that you attach the arm to. yes, a 1/4 will make a difference
The dimension they are giving is for the shaft that the wiper arm attaches too---has to be the right size. Take the old wiper arm off and measure the diameter of the shaft it goes onto to get the correct size. Splines are the little grooves on the shaft that keep the wiper arm from rotating on the shaft while operating and must be lined up with grooves in the wiper arm to line up on the glass properly.
