My advice to the proud owner of the J.J. Taylor safe that figured out the correct dialing procedure and wants to change the combination is to call in a competent, experienced, safeman to checkout the entire safe and do the combination change.
The lock and related mechanism of the safe probably hasn't been serviced in years and while it may only require a combination change, it may benefit from a good cleaning and lubrication and replacement of any defective or worn parts.
Locking bolts have also been known to get bent over the years.
While changing the combination of a safe or vault may seem simple, if you make a mistake, you can lock yourself out and require an expensive, multi-hour, service call to get into the safe!
To find a good SAFEMAN, try asking your bank manager who they use or look in the Yellow Pages and phone around, requesting references which you actually check out.
If J.J. Taylor became part of Chubb, Mosler, Taylor, try calling your local dealer or authorized service company for that brand of safe.
The money you pay to have the lock and safe checked over and combination properly changed is well worth it as a lockout will probably cost a whole lot more!