My dad just had to replace brake shoes and rotors on the rear of his truck. We do a lot of driving on gravel roads. The stones wore away at the rubbers that protect the bolts that the calipers slide on and they seized. The shop where he had it fixed at said there were shields available to protect the calipers. Has anyone had this trouble before? We are going to get shields put in place and I will change my bolts and rubbers so I don't have any trouble.