TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 1/TASK 1
During normal operation, the accumulator is charged by fluid from the
pump port. This fluid is taken from the pump port before it gets to
the spool valve.
The charging fluid flow is controlled by the
accumulator valve which consists of a check ball, spacer, plunger,
and plunger seat.
The check valve allows fluid under greater
pressure than that in the accumulator to go through the valve and
into the accumulator.
Once past the check valve, the fluid then
travels by internal passage to the accumulator.
The fluid pressure
exerts force on the accumulator piston which then compresses the
This fluid is then stored under pressure until normal
fluid pressure is not available.
The steering system on the HMMWV is a hydraulically assisted
wheel, steering gear, power steering pump, hydro-boost, lines,
steering column, steering linkage, tie rod, center link, idler arm,
and pitman arm.
The turning effort at the steering wheel is
transmitted to the steering gear where it is hydraulically multiplied
and transferred to the front wheels through the steering linkage.
Components of the Steering System.
In the paragraphs that
follow, each of the components of the HMMWV steering system will be
(1) Steering Wheel. The steering wheel is a three-spoked, 15 1/2
inch steering wheel with a center-mounted horn button. It is secured
to the upper steering column with a hex nut.
(2) Steering Column. The steering column is a two-piece assembly
consisting of an upper steering column and an intermediate steering
The two pieces are universally-jointed and the intermediate
shaft is also splined to the steering gear stub shaft and secured
with a bolt through the slip yoke.
(3) Power System.
The power system is composed of the steering
supply is maintained in a reservoir that is mounted on the power
steering pump. The pump is operated by a