As a professional clock restorer,and repairer,the first thing i will say is All mechanical clocks need to be cleaned and serviced about every 5 years,all the oil will thicken etc..As this is the most common problem,take it to a competent repairer,or horologist.Preferably a member of a professional organization,such,as THE BRITISH WATCH AND CLOCKMAKERS GUILD,OR BRITISH HOROLOGICAL INSTITUTE,,,.
In most cases,trying yourself will cause damage,(i have an example on my bench now,would have cost about £100,but now £250,due to owner damaging the clock)
It requires great skill and exsperiance,plus special tools,chemicals,and at least 3 types of oil,and often grease,Non available,usually for the public.
As most clock,particularly carriage clocks are valuable,it makes no sense,for the amateur to attempt repairs.(i repeat after say 5 years or so a complete strip clean and overhaul,is required,due to tacky oil,dirt,dust,etc.,)
Any repairs,replacement parts,springs,etc.,are beyond most amateur repairers,and parts not easy to find.
I manage to repair many simper things,and save money,But leave valuable clocks to the experts'
R.C.WOODHOUSE,HUNSTANTON NORFOLK
Robert Woodhouse, February 2016