On site we have a 2 MVA oil filled transformer 6.3kV/0.42kV. There is a small leak form the bushing base connection to the transformer tank. We want to replace the gasket of the bushing. Is there any procedure for this kind of activity? I guess that the bushing needs to be lifted somehow, take out the old gasket and replace it with the new one. But also the tank oil will be exposed to atmosphere also we might need oil recirculation and o2 measurement and of course during the work execution to make a small kiosk around the area with the use of dehumidifier. Any proposal will be appreciated.