You have set yourself a rather difficult task, because nowadays it is quite difficult to find spare parts for excavators, unless you write directly to manufacturers and try to buy spare parts from them, but the chance that this will work is very small, so I advise you to turn your attention to new holland parts catalog
With this catalog, you will surely be able to find all the parts you need for your excavator. Hope I helped you.

Hello to everyone! Could you please tell me where I can find parts for New Holland excavator?

Whoa! I'm surprised someone on this forum has an excavator. Well, anything can happen.
You're in luck, because I know how to help you. You should read the excavator repair manual
Here you can find all sorts of reasons for the breakdown of your excavator and how to fix them.
My father has his own small construction firm and this manual helped him a lot!
There are you can also find Heavy Equipment repair manual, including dozers, wheel loaders, motor graders, skid steer loaders, etc

Hello everyone! My excavator has just broken down. Does anyone know any repair manuals? I'll be so grateful!