Just rebuilt my bobtach on my 753. Talk about a lot of work. Never did get the locking pins to move. Lots of penetrating oil and a rosebud with a BFH didn't work. Cut them out and used sch 80 1 1/4 pipe for sleeves. Put replacement sockets in the plate and arms. Didn't have the money to get the arms line bored so I just used a torch. Kinda ugly holes but after welding nobody knows. put it together to align every thing and welded away. Not perfect but will work for me. being broke sure makes you work hard.