Repacking boom cylinders

Can this be done on the main boom cylinders in-situ just pulling the rod out?
Reason being that i cant get it to a shop and cant see how i can push out the bottom pins due to all the steel in the way...cab etc...
With the main cylinder casing on the machine it would mean no vice and heavy lifting to brace the thing.

Excavator is a Kobelco SK120

Anyone have any tips on this job? Ive never touched one before.

Thanks

Repacking boom cylinders