S 216-470

 (3)  
Do the steps which follow to examine the differential pressure indicator for the case drain filter of the power transfer unit (PTU) (Fig. 601).

 (a)  
Make sure the red indicator button on the differential pressure indicator did not come out.

 (b)  
If the red indicator button came out, replace the filter element and set the red indicator button for the case drain filter of the PTU (AMM 29-22-05/401).

 (c)  
If the case drain filter contains many metal particles, replace the PTU (AMM 29-22-01/401).

 S 416-471
 WARNING:_______USE THE PROCEDURE AMM 32-00-15 TO REMOVE THE DOOR LOCKS. THE DOORS OPEN AND CLOSE QUICKLY AND CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (4)  Remove the door locks from the landing gear doors and close the doors (AMM 32-00-15/201).
 TASK 29-11-00-796-030
 7.  Hydraulic System External Leakage Check_______________________________________
 A. General
 (1)  This procedure gives the external leakage limits which are permitted for normal operation and for dispatch of the airplane to avoid a delay. An external leakage rate which is not more than these limits will not have a bad effect on the component or system operation. You must make an analysis of each of the leakage rates to make a decision on the maximum total leakage rate that the average length of flight will permit.
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 29-11-00
 ALL  ú ú 01 Page 616 ú May 28/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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757
MAINTENANCE MANUAL

 (2)  The conditions which follow are important when you do a leakage check for the various components:
 (a)  
Metal-to-metal surfaces make the seal at the B-nut tube connections. If a leak does not stop when you tighten the B-nut to the correct torque, the joint is defective and you must repair it.

 (b)  
Measure the leakage with hydraulic pressure supplied to the component.

 (c)  
Where possible, operate the actuators to see if the leakage changes during the travel.

 (d)  
Make sure the leak is not a type which will increase to a much higher rate with time. Use the type of leak and the length of time the component has pressure on it to make this decision.

 (e)  
If a component has a continuous leak, or a leak that can possibly increase with time, check it a minimum of once daily, to make sure that leakage does not exceed limits shown in Table
　
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