TM 10-3930-671-10 Know The Truck Truck Components & Features TA18 Brake System Service Brake Dual foot pedals are connected to two master cylinders.  Service brakes can be applied with both pedals. Trucks have a manual (not powered) brake system.  The master cylinders apply pressure, through brake lines, to drum and shoe brakes at  drive  wheels.    Brakes  are  self-adjusting.    Service  brakes  are  mechanically  actuated  for  parking.    Brake  system  is  a closed circuit using silicon hydraulic brake fluid supplied from a separate reservoir. Inching Brake Left pedal is for normal inching control.  Pushing gradually on pedal will smoothly disengage transmission. Pushing pedal further will apply service brakes. Parking Brake A  parking  brake  is  provided  by  mechanical  actuation  of the service brakes.  A hand-operated parking brake lever mounted at the dash is connected by cables to the brake assemblies, one to each drive wheel. Main Hydraulic System/ Power Steering System The parts of the main hydraulic system are the hydraulic sump tank, main hydraulic pump, priority demand valve, main   control   valve,   hydraulic   oil   filter,   and   associated hydraulic lines and hoses. The hydraulic sump is a separate, removable tank bolted in the right side compartment of the truck frame where it is protected from damage.  It has a large opening at the top    with    a    removable    cover    which    includes    the    fill tube/breather,  oil  level  dipstick,  and  oil  filter  return  line. The cover is held on with a V-clamp for positive sealing and ease of servicing.  The sump breather is a standard Clark part with a nominal 10 micron © 98.5% efficiency rating. The main hydraulic pump is mounted to an SAE pad on the transmission driven by a silent chain from the engine The   main   hydraulic   control   valve   features   adjustable system   pressure   relief   valves   and   a   counterbalance valve in the tilt circuit with a pressure compensated flow control   valve   to   control   tilt   speeds.      All   ports   and connecting lines are on the bottom surface of the valve. The side shift attachment uses a single auxiliary section on the outer (RH) side of the standard (lift/tilt only) main valve. The  side  shift  attachment  also  has  an  adjustable  relief valve and can be assembled  with  optional  flow  controls for 2.5, 4.0, 5.5, 7.0, or 10.0 gpm flow level. The   hydraulic   system   relief   pressure   level   is   "tuned" (adjusted)   to   match   the   need   of   each   truck   rated capacity.  Maximum pressure is 3000 psi (20,700 kPa) . A  diagnostic  demand  valve  allows  access  for  checking main hydraulic and steer system pressure. E-43