These a-arms have the old style urethane bushings that cannot be replaced from Cat, but RTR Custom Fab has replacement UHMWPE bushings. I did my 05 300 last May. The 250 and 300 are virtually identical machines. Contact @ricktherocket on this forum for pricing. The other thing I noticed with these machines is the toe in / toe out changes when you push down on front end or lift up on it. Before I changed the bushings they leaned in at the top and were toed out.