Ascaso coffee machine makes very loud rattling or buzzing noise from the pump during brewing.

Basic checks:

• Bleed air: Run water through the group and steam wand with no portafilter to purge air from the pump and lines.
• Check water tank: Ensure the tank is full and properly seated to avoid sucking air.

Internal inspection (unplug first):

• Inspect pump mounts: Open the housing and check that the vibration pump is firmly held in its rubber mounts and that the mounts are not cracked or hardened.
• Tighten brackets: Secure any loose brackets or screws that allow the pump to vibrate against the chassis.
• Replace mounts or pump: If noise persists and mounts are degraded, replace the rubber mounts. If the pump is also weak or inconsistent, replace the pump assembly.