NMC-WOLLARD MB-4 200-DF, Operation, Maintenance And Parts Manual

Page: 76 / 321

7.1 STEERING SYSTEM OVERVIEW
The system is hydraulically assisted and
uses a hydraulic cylinder built into the axles
to move the tie rods which in turn pivot the
wheel hubs.
Before servicing the steering system, in-
spect and clean steering system compo-
nents.
Also see Section 9 for axle lubrication infor-
mation.
7.2 STEERING COLUMN
7.2.1 Removal
1. Disconnect external horn wire from un-
der dash panel.
2. Remove rubber horn button from steer-
ing wheel by peeling it from plastic horn
base.
3. Remove plastic horn base by turning and
pulling it. There is a spring and spring
seat assembly under the base. Take
care not to lose them when removing the
horn base.
4. Remove nut and flat washer from top of
steering column shaft. Hold your hand
under steering wheel while removing
wheel. There are two carbon brushes
and a spring which will fall out. Remove
steering wheel assembly. Wheel is
keyed to serrations on steering shaft.
5. Place nut and washer on steering col-
umn shaft to prevent loss.
6. Remove bolts at top of dash panel and
tip panel toward driver’s seat.
7. Remove bolts holding orbitrol (steering
gear) to steering column and push
orbitrol toward front of tractor to clear
steering column.
8. Remove bolts holding steering column in
bracket and push steering column out
through back of dash panel.
7.2.2 Installation
1. Push steering column through back of
dash panel and attach column to bracket
with fasteners. Push orbitrol up and onto
steering column, check engagement,
and reattach with screws.
2. Tip dash panel back and fasten into
place with screws.
3. Remove nut and washer from steering
shaft and install steering wheel assem-
bly. Tap into place on shaft serrations
with a soft-faced hammer. Install nut and
washer to secure steering wheel to col-
umn.
4. Insert plunger into counterbored hole in
steering wheel. Install horn parts.
5. Connect external horn wire. Test opera-
tion of horn.
7.3 ORBITROL STEERING GEAR
7.3.1 Removal
1. Remove screws from top of dash panel
and tip panel toward driver’s seat.
2. Remove screws holding steering column
to orbitrol and push orbitrol away from
column.
3. Relieve pressure on hydraulic system.
4. Mark and remove hoses from orbitrol.
Plug ends to eliminate system contami-
nation.
7.3.2 Installation
1. Unplug and reattach hoses at proper
ports.
2. Push orbitrol onto steering column and
check engagement.
3. Tip dash panel back and fasten with
screws
.
M200 MB4 Tow Tractor Manual No. 42975
PAGE 7-2
JULY 15, 2001