first you have to get into the tower in rock ridge, then you go all the way to the end and get on the ladder then, without falling, you make your way to the clock, grease it up [only the middle gears] and you get the clock going! it's really quite simple once you get the hang of it, DON'T GIVE UP!
Diamond plains
in diamond plains
go to the train station
You oil it.
it is located at the diamond plains
After you oil the clock gears the clock will strike 3:00.
The clock tower is in Diamond Plains, to the right of the section with the marshal's office and the saloon.
You go out the way you came in, just reverse
the gears in the clock tower
The oil can is used to oil the gears of the clock in the clock tower at Diamond Plains, so that the clock will work again.
the clock is in the tower. if you go all the way to your right they are doing construction and if you go inside theres the clock!
just play the game and you will find out.;)