Abstract: The invention provides for the removal and replacement of a partially fibrous camshaft gear while engine (E) is in situ within a chassis. The method comprises chipping away the fibrous section of the gear, splitting the metal hub with a device (S) which peripherally surrounds the hub and forces a wedge into it, and forcing the replacement gear onto the camshaft using a press (P) whihc is mounted to the engine, and which utilizes the chassis as a brace during the development of pressure against the replacement gear. The press device (P) includes three members. The first member (38) mounts the press to the crankshaft, and accommodates engines with varying distances between the crankshaft and camshaft. The second member (40) is affixed to the first member (38) so that in conjunction with the first member the chassis (54) is accommodated and serves a bracing function.