There is another gentleman on this board that faced similar problems with a B-21 that he purchased from a rental yard. The
HST went "Tango/Uniform" shortly after the sale, even though the
HST had been rebuilt prior to the sale?
He totally dismantled the tractor, and showed step-by-step, the rebuilding of the
HST an other issues, which included many detailed photos of critical parts of the
HST, that may have been overlooked on the prior rebuild?
His project was about a year ago, or less, and you may want to do a search; he is very talented with attention to details too!