TM   10-3930-638-24&P 2-43. SERVICE BRAKE MAINTENANCE (cont) c.  Hydraulic  Brake  Valve  (cont). (2) Power Assist Unit. This task covers: a.  Removal b. Disassembly c. Cleaning INITIAL  SETUP TOOLS No. 1 Common Organiza- tional  Maintenance  Tool  Kit Hard Wooden Blocks (2), 6 by 6 by 18 inches MATERIALS/PARTS Cleaning  solvent  P-D-680 Clean cloths Power assist unit repair kit d.  Inspection e.  Reassembly/Repair f.  Installation/Replacement EQUIPMENT   CONDITION NSN  4910-00-754-0654 Paragraph Condition Description Engine  off, Vehicle  parked  on  level  surface,  wheels blocked,  and  parking  brake  applied. 2-43c(1) Brake  master  cylinder  removed. 2-48b(2) Hydraulic  lines  and  fittings  disconnected from power assist unit. 2-43e Brake  pedal  and  declutch  pedal  removed. 2-302