B-701964-00 Rev. C Service and Repair 5-11Companion 1000/T Liquid Oxygen System Technical Manual5.7.1 RemovalRefer to Figure 6-5 to identify parts with bold number references.1. Remove side cover B (Section 5.2.1, steps 1 and 2).2. Loosen and remove the silencer 6 from the end of the primary relief valve 5 (Figure5-13).Figure 5-133. Use a 1/2-in. open-end wrench to loosen and remove the primary relief valve whilesimultaneously holding the relief valve adapter 4 stationary with another 1/2-in.open-end wrench.Figure 5-14Some older models may not be equipped with a silencer. These units may beretrofitted with a silencer, but this will require replacing the primary reliefvalve.• Inspect the relief valve adapter for cracks caused from overtightening. Replace asnecessary.• Some older models contain a blue, anodized relief valve adapter. Some of theseadapters may be susceptible to cracking. The blue relief valve adapter has beenreplaced by a clear anodized adapter that has a longer thread engagement length(refer to parts list).• The primary relief circuit tubing on some older models consists of a "pig-tailed"section of aluminum tubing. The current primary relief circuit tube is a long,U-shaped section of aluminum tubing. (Refer to parts list and Figure 6-5.)