How to repair diffusion pump

We were four Ph.D students and we had one Electron beam welding (EBW). Hence we had to book the machine in advance.In case the machine goes out of order when you are working it is your responsibility to put the the machine back in to working. You cant walk away if the machine is down.
Vacuum in the welding chamber is created by one mechanical pump and one diffusion pump. First the mechanical is switched on and after the desired vacuum is achieved in the chamber, the mechanical pump is isolated by closing a valve and then a valve is opened to connect the diffusion pump. If by chance the diffusion pump is brought in to operation with out isolating the mechanical pump, air will rush in to the diffusion and the oil in the diffusion pump will burn and the diffusion pump stops operation. Then you have to clean the diffusion pump and put it back in to operation.
One day while working in the machine I opened the wrong valve and the diffusion pump conked off. I shut off the machine and was waiting for some worker to come and dismantle the pump and repair it.Prof. Olshanskii happened to come to the laboratory and saw me not working. I told him that the diffusion pump is not working. "Repair it". I told him I don't know how to repair it. He shouted"Then learn it". He called the foreman of laboratory and asked him to give me a set of tools. He then told me to dismantle the pump and see what has gone wrong.He saw me struggling to open the heavy bolts he provided me a hefty worker,Kolya, to dismantle the pump. When the pump was dismantled I found that the internal shrouds in the pump was coated with a thick layer of burnt oil. The shrouds were made of aluminium and cleaning process involved using emery papers to remove the muck accumulated on the shrouds. It is slow and back breaking.Here Kolya helped me. After cleaning every shroud, they have to be degreased for which industrial alcohol was used. By the time cleaning was over it was late in the night and Kolya agreed to fix the diffusion pump in position. I left for my hostel. Next morning I was hauled up before the Foreman of the laboratory because Kolya drank the rest of the alcohols and had passed out in the laboratory. It seems that it was my responsibility to have used the entire alcohol for cleaning and not leave with the worker! This experience gave me confidence that I can repair any diffusion pump.