forgot to add in earlier post that Mycom will recommend change of shaft seal o/ring material compound as well,if using sythetic oil, your Mycom supplier should know that and advised you already. Stops leaking during operation due to oil / ammonia/ heat vacuum thing, Alignment on coupling is highly critical, recommend laser alignment, maximum total at mis-alignment less than 0.003, any measurment, radial . height , face to face, any which way. Mycom supply that sevice internationally.
hope this all helps.
magoo