B757-200
Maintenance Airframe; Maintenance Powerplant
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Critical
General Maintenance Action
Chart Or Publication; Aircraft; Human Factors; Manuals
Reference MM 26-16-02-directs Mechanic to 'put the spacers below the blower mounting pads'. Reference Illustrated Parts Catalog (IPC) 26-16-01 Items Number 35 (Spacer) and Number 40 (Gasket). IPC Item Number 35 must be installed in a specific manner; as flipping it will restrict airflow; possibly causing the blower to fail prematurely. Item Number 35 in the IPC is a spacer with a cutout in it to allow airflow through the spacer; but this is not specified in the MM or IPC installation instructions. [Recommend] providing clarification and clear graphic showing exactly how the Item Number 35 should be oriented under the blower; as currently there is no clear direction and incorrect installation is quite possible and easy to do; as the location is not easy to remove/replace (r/r) the [vacuum] blower; with limited access.[During] ETOPS pre-departure check.
A Line Mechanic reports about the lack of specific orientation of spacers and gasket for cargo pit Smoke Detector Assembly vacuum blowers in their B757-200 Aircraft Maintenance Manual (AMM) and Illustrated Parts Catalog (IPC). Incorrect installation will restrict airflow and possible premature blower failure.