we recently purchased a very old 600 series Champion grader (without a manual) with a 671 Detroit diesel. I beleive it is a 1960's vintage. It runs very well still however we are now encountering some steering problems. It has a Sheppard steering box Model 514 I beleive, which we are having trouble finding any info on. THe grader has trouble steering to the right - to the left is not a problem. ANy sugguestions on what might be the cause or any info on a website that we can trouble shoot the the inner workings of the Sheppard sterring box?