I am having the head gasket replaced on a 1983 Mercedes Benz 240D that I have owned for the past year and would like to keep. Body is in great shape and I have been making small improvements over the past year.
I am not a mechanic, so I was wondering if it would be smart to also replace the chain belt while doing this work. How many miles is the belt good for? Is this easily accessible while replacing the head gasket?

Also, I owned another 240D whose vacuum pump tore up. My mechanic said that it threw parts all throughout the engine and unless you were going to rebuild it completely, it was history. With this past experience in mind, would it also be wise to replace this vacuum pump while having the head off and replacing the head gasket?

Any experienced help would be appreciated.
George