Bleed Brakes / Replace Brake Fluid Completely

Hello, diesel mechanics.

I installed a larger master cylinder in my Golf 2 with a TDI AFN engine.
Do I need to replace the entire brake fluid now, since air bubbles have formed directly in the brake lines near the master cylinder?
What's the best way to proceed, as I still have 5 liters of ATE brake fluid in my garage.
Best regards.
Olli.

First, bleed the connections at the heat pump unit until liquid starts to emerge, then close them.
Then, bleed all the wheels.
How else would you be sure that there aren't any air bubbles left somewhere?
Hopefully, your kettle is in good condition and not old or unusable. If in doubt, have it tested beforehand, or boil it.

Hello.

Thank you for the quick response. I'll start bleeding the brakes tomorrow.
Best regards and a great start to the week.
Olli.