Many times in my association with cars have i got into situations when trying to fit parts where i have begun to believe that the parts are faulty and they just ai'nt gonna fit

Usually by that time steam is pouring from my ears and spanners are airborne !
Best advice i can give is have a break,make a cuppa and then go back to it after 20 minutes or so.
You might just get that light bulb moment and work out why it's not going as hoped and then get it sorted
