1983 400I suspension pump

I just had my shocks rebuilt on my 1983 400I. The car was running properly however, my mechanic says there are intermittent problems with the accumulator pump. Can they be repaired? He thinks it may be a valve problem is it’s just better to replace it? Any advice on where I can get a replacement? I remember reading somewhere on Ferrari Chat That the Mercedes Accumulator is similar to the Ferrari 400 I. Any advice? Thanks