M.  When you remove, install, or do work with hydraulic tube assemblies, obey the guidelines that follow:
 (1)  When you remove tubes, make sure the tubes and port fittings have tags that identify the correct connection locations.
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 (2)  
Do not move or change the tube bends. If you move or change the bend in the tube, these bad effects can occur:

 (a)  
If you move or change a bend in the tube, it can become possible that the tube will align with the incorrect port. If this occurs, incorrect reconnection or cross-connection of the tubes can become possible.

 (b)  
If you move or change the bend in the tube, it can be possible that the tube will have too much stress when it is connected. Stress can cause cracks in the tubes.

 (3)  
If you disconnected more than one hydraulic tube and you think there is a possibility you connected the tubes incorrectly or cross-connected the tubes, do an operational check:

 NOTE: Use your own judgement to determine if a check is necessary.
____
 (a)  Do the post-installation test of one or more of the components to which the tubes are connected as a check.
 (4)  If you disconnected electrical wires to get access to the tubes and you think there is a possibility you connected the wires incorrectly or cross-connected the wires, do an operational check:
 NOTE: Use your own judgement to determine if a check is necessary.
____
 (a)  Do the post-installation test of one or more of the components to which the wires are connected as a check.
 N. Hydraulic system pressure definitions are below.
 (1)  
Maximum working pressure:

 (a)  Anytime repairs to the tubes are made on the airplane, or when any hydraulic component is to be checked.

 (2)  
Proof Pressure:

 (a) If the tubes are repaired and to be tested in the shop.

 (3)  
Burst Pressure:

 (a)  This is for design reference only.
 O. B-Nut torquing:
 (1)  
The correct torquing can be applied to B-nuts only if the tubing material is identified correctly (aluminum, titanium or steel).

 (2)  
If the normal finish color of the B-nut is covered by the grey drilube coating, a color-coded ring is applied to the back side of the B-nut.

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 ~................................................................. | | | B-NUT (MAY BE | | TUBE | | COVERED WITH | | MATERIAL | TUBE FINISH/COLOR | DRILUBE) | ................................................................... |ALUMINUM |STANDARD 767 - GREEN PRIME |GOLD OR BROWN | ................................................................... |CRES |STANDARD 767 - NO FINISH |Silver, Bright | ................................................................... |TITANIUM |NO FINISH |Dull Gray | 2............…................................…...................1
 (3)  If a steel or titanium B-nut connects to an aluminum tube or fitting, use the lower torque value (aluminum).
 P.  To install oxygen system tube assemblies, refer to Chapter 35, Oxygen. You can use this procedure to preset or swage flareless sleeves for oxygen system tube assemblies. You must make sure the oxygen tube assemblies are clean and free of oil (refer to the Component Maintenance Manual Instructions).
 Q.  Use the tube materials as shown in Table I. Use the approved tube materials/tube sizes/tube wall thicknesses as shown in Table IA for 3000 psi hydraulic systems.
 ~............................................................................... | TABLE I | | CROSS REFERENCE OF TUBING TO BMS/MIL SPECIFICATION | ................................................................................. | TUBING MATERIAL | BMS | MIL | OTHER | ................................................................................. |ALUMINUM 6061-T4, 6061-T6 | ---|WW-T-700/6 *[1]| ---| | | | T-7081 | AMS 4083 | ................................................................................. |CRES 21-6-9 | 7-185 | ---| ---| ................................................................................. |1/8 HARD CRES 304-1/8h | ---| T-6845 | AMS 5566 | ................................................................................. |ANNEALED CRES 304 | ---| T-8504 | AMS 5567 | ................................................................................. |ANNEALED CRES 321 | ---| T-8808 | AMS 5556 | | | | | AMS 5557 | ................................................................................. |TITANIUM 3AL-2.5V | 7-234 | ---| AMS 4945 | 2............................…...................…...............…..............1
　
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