On my 53 the front cab bolts have a 1/4"x2x2 rubber pad that mounts between the cab and frame. The rear cab mounts are shackles. I don't think replacing the rubber is going to solve your problem, you might try loosing the front cab to frame bolts and see if the cab will shift over a little. Also, it wouldn't hurt to replace the clutch and brake felt seals where they go through the toe plate.
