INTRODUCTION TO THE HMMWV - OD1615 - LESSON 3/TASK 1
This fluid is then stored under pressure until normal fluid
pressure is not available.
The steering system on the HMMWV is a hydraulically assisted power steering
system comprised of the following components:
steering wheel, steering
gear, power steering pump, hydro-boost, lines, steering column, steering
linkage, tie rod, center link, idler arm, and pitman arm.
effort at the steering wheel is transmitted to the steering gear where it is
hydraulically multiplied and transferred to the front wheels through the
a. Components of the Steering System. In the paragraphs that follow,
each of the components comprising the HMMWV steering system will be
b. 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.
c. Steering Column.
The steering column is a two-piece assembly
consisting of an upper steering column and an intermediate steering shaft.
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
d. Power System.
The power system is composed of the steering gear,
power steering pump, and interconnecting hoses.
The fluid supply is
maintained in a reservoir mounted on the power steering pump. The pump is
operated by a drive belt mounted on pulleys attached to the pump shaft and
the engine crankshaft.
The power steering system on the HMMWV holds one
quart of Dexron II hydraulic fluid.
The gearbox used in an integral power steering system is basically a manual
gearbox adapted to include a power assist package.
The integral power
steering gearboxes are of two types: offset and inline. However, since the
HMMWV uses the offset or recirculating ball bearing type of gearbox, that is
the only one that will be discussed in this text. The offset type uses a