Maintenance Manager reported non compliance with MEL procedure and incorrect maintenance practices led to water leaking into the Lower avionics compartment; causing system failures on a B747 aircraft.

Narrative

Aircraft X arrived in ZZZ1 for a fuel and tech stop upon post and pre-flight inspection Maintenance tech found water pouring out of the CAC door area the Maintenance tech contacted Maintenance control and advised them of the finding. They were informed to deferred maintenance instruction and deactivate the water system and keep the plane moving to next stop; after which the aircraft was going to ZZZ for Maintenance and will be addressed. The aircraft arrived in ZZZ on Date 1 and the Maintenance Manager of ZZZ told ZZZ staff to not get into anything and keep the plane green and they just wrote off the leak as not found. When asked if they worked it; he threatened myself saying he would never put his team on the spot again; and is releasing the aircraft into service with a known leak into a compartment that has computers and Inertial Reference Units (IRU). Company has very poor to no accountability and zero concerns from FAA as they always seem to get out of any investigation here is the email First off understand the following:That Plane was never supposed to come here. They had no place to park in ZZZ2 and asked if we can make room for it at the very last minute. We were told to not work anything since everything was planned for another station but; we elected to. The plan was to keep the plane Green so that we didn't risk starting something that could potentially AOG the plane. Don't you ever put my team on the spot like that ever again. I understand they didn't find a leak but this is what's causing the brake problems. The computers are soaked in flight the system gets serviced and with the APU running its pouring water. And if they did do any looking the cooling duct for the brake computer would be obvious it's laying in the water under the rack.