TM 10-3930-669-34 15-8.  MAST SECONDARY CYLINDER REPAIR. This task covers: a. Disassembly b. Cleaning/Inspection c. Assembly INITIAL SETUP Tools and Special Tools Equipment Condition Tool Kit, General Mechanic’s: Automotive Mast secondary cylinder removed (Item 1, Appendix E) (Para 13-2) Vise, Pipe, Chain (Item 5, Appendix E) Pan, Drain (Item 11, Appendix E) Materials/Parts Oil, Hydraulic (Item 15, Appendix B) Solvent, Dry-cleaning (Item 20, Appendix B) Ring, Wear Ring, Wear (2) Kit, Seal a. Disassembly. NOTE There are two mast secondary cylinders.        Both    are    repaired    the same way. (1) Position   mast   secondary   cylinder   (1)   in   chain vise. CAUTION Do  not  allow   threaded   or   machined surfaces    to    come    in    contact    with other    metal    surfaces.        Clearances between cylinder components is very small, any minor damage done during disassembly could require component replacement or make assembly difficult. (2) Position     drain pan under mast secondary cylinder (1). (3) Remove base (2) from cylinder (1). (4) Remove backup ring (3) and preformed packing (4)   from   base   (2).      Discard   backup   ring   and preformed packing. 15-51