Freightliner FLA/FLB/FLC/FLD/FLL. Manual - part 4

The M4 Maintenance Interval Operations table lists
all maintenance operations that are to be performed
at the M4 maintenance interval. Maintenance opera-
tion numbers are reference numbers used to help
you find detailed instructions in this manual on the

maintenance operations to be performed. Perform all
maintenance interval operations in M1, M2, and M3
when performing M4 maintenance interval opera-
tions.

M4 Maintenance Interval Operations for Service Schedules I, II, and III

Maintenance

Operation Number

Operation Description

Check

00–07

Perform all M1 Operations

00–08

Perform all M2 Operations

00–09

Perform all M3 Operations

20–02

Radiator Pressure Flushing and Coolant Changing

26–05

Allison Transmission Fluid and Filter Changing

42–12

Bendix Air Dryer Desiccant Replacing (AD–2)

42–13

Bendix Air Dryer Desiccant Replacing (AD–4 or AD–9)

42–23

Meritor WABCO System Saver 1000 Air Dryer Desiccant Replacing

General Information

M4 Maintenance Interval Operations Table: 00-10

00/17

Cab-Tilt System

The Power-Packer

cab-tilt system has four major

parts (see

Fig. 1

•

A hydraulic pump consisting of a pump body, a
reservoir, and a pump control lever.

•

Two hydraulic tilt cylinders that raise and lower
the cab.

•

A shift-disconnect cylinder that allows the shift
tube to extend during cab tilting.

•

A tilt strut on the right-side tilt cylinder, which
must be used when working under a cab that
has not been fully tilted.

The optional air/hydraulic system has the same
major parts as the hydraulic-only system, but has an
additional air motor assembly attached to the tilt
pump. See

Fig. 2

. The air motor normally operates

the tilt pump in place of the manual pump control
lever. If for any reason the air motor is not working,
the tilt pump can be operated with the manual pump
lever.

f310031a

07/03/97

A. Tilt Pump Enlargement
1.

Tilt Strut

Right Tilt Cylinder

"Push" Port Fitting

Pump Body

Pump Control Lever

Pump Lever

Reservoir

"Push" Port Fitting

"Pull" Port Fitting

10. "Push" Port Fitting
11. "Pull" Port Fitting
12. Left Tilt Cylinder

13. Shift Tube
14. Shift Tube Latch Mechanism
15. Shift-Disconnect Cylinder
16. Fill Plug
17. Fittings

Fig. 1, Hydraulic-Only System, Equipped With Mechanical Cab Latches

General Information

COE Cab Tilting, FLA/FLB: 00–11

00/18

On FLBs, cab latches are hydraulic, and are
plumbed into the cab-tilt system.

The tilt cylinders are connected to the pump by flex-
ible high-pressure lines. Velocity fuses are built into
the tilt cylinder ports. They act as check valves to
prevent the cab from free-falling in case of hydraulic
system damage, such as a ruptured line.

There are two hydraulic circuits in the Power-Packer
system: the

push

circuit raises the cab from the low-

ered position to the desired tilt position, and the

pull

circuit brings the cab from a tilted position up and
over center. See

Fig. 3

Placing the control lever in the "Raise" position
opens the

push

circuit in the hydraulic system. When

the mechanical cab-hold-down latches are released
and the pump is operated, hydraulic pressure builds
in the tilt cylinders and the shift-disconnect cylinder. If
equipped with hydraulic cab latches, hydraulic pres-
sure releases the latches. As pressure increases, the
shift-disconnect cylinder releases to allow the shift
tube to telescope out. Then the tilt cylinder piston
rods extend, raising the cab. When the cab goes

over center, it falls at a controlled rate to the full-tilt
position, automatically relieving hydraulic system
pressure.

When the control lever is placed in the "Lower" posi-
tion, the

pull

circuit in the hydraulic system opens.

When the pump is operated, hydraulic pressure
forces the cab back up and over center. The cab
then falls at a controlled rate until it settles onto the
rear mounts.

NOTE: Whenever raising or lowering the cab,
stop working the pump once the cab goes over
center. The cab falls at a controlled rate, and
continued pumping could cause hydraulic
lock-up of the tilt cylinders.

Hydraulic lock-up of the tilt cylinders can occur dur-
ing very cold weather. It can also occur when the
wrong hydraulic fluid is used, when there is air in the
system, when there is sudden cab movement, or
when a hydraulic line is ruptured. Any of these situa-
tions will cause the velocity fuses to function as
safety check valves, and lock up the tilt cylinders.

IMPORTANT: If the tilt cylinders lock up, check
for a major problem (such as a ruptured line or

03/02/98

f310359a

A. Air supply connects here.
1.

Shift-Disconnect Cylinder

Tilt Strut

Right Tilt Cylinder

Air Motor Assembly and Button

Reservoir

Manual Pump Lever

Pump Control Lever

"Push" Port

"Pull" Port

10. Right Hydraulic Cab Latch
11. Left Hydraulic Cab Latch
12. Left Tilt Cylinder

Fig. 2, Optional Air/Hydraulic System, Equipped With Hydraulic Cab Latches and Cab Air Suspension

General Information

COE Cab Tilting, FLA/FLB: 00–11

00/19

leaking fitting) before trying to unlock the tilt cyl-
inders. If such a problem is found, make any
necessary repairs before unlocking the cylinder.

To unlock the cylinders, the cab must be moved in
the opposite direction of travel (back toward the 45-
degree position). If the cab is moving toward the full-
tilt position when the lock-up occurs, move the con-
trol lever to "Lower," and work the pump a few
strokes to unlock the cylinders. Move the control
lever to "Raise," and allow the cab to descend to a
full-tilt position. If the cab is moving toward the low-
ered (operating) position when the lock-up occurs,
move the control lever to "Raise," and work the
pump a few strokes to unlock the cylinders. Move the
control lever to "Lower," and allow the cab to de-
scend to the operating position.

Tilting the FLB Cab

CAUTION

Before tilting the cab, make sure the vehicle is
parked on level ground, both side-to-side and
front-to-rear. Tilting the cab while the vehicle is
parked on unlevel ground (such as a sloping high-
way shoulder) may damage the cab mounts and
prevent you from returning the cab to the operat-
ing position.

Apply the parking brakes. Place the transmission
shift lever in neutral. Shut down the engine if it is
running.

WARNING

Before tilting the cab, make sure that there is ad-
equate clearance in front of the vehicle, and that
the area is free of people and all objects.

Do not tilt the cab with the engine running. Tilting
the cab could engage the transmission. If the en-
gine is running, the vehicle can move, causing an
accident that could result in personal injury or
property damage.

Secure all loose articles in the cab and bunk,
and make sure the doors are securely latched.

WARNING

Objects falling in the cab, or a door flying open,
could damage the vehicle or cause personal in-
jury.

Move the pump control lever to "Raise."

Operate the pump (using the manual pump
handle, or the air control button if so equipped)
to disengage the hold-down latches.

IMPORTANT: Check the indicator pin on each
cab latch. The latches have disengaged if the
pins are out. See

Fig. 4

If air is present in the hydraulic tilt system,
pump operation will seem "spongy" or ineffec-
tive. If this happens, bleed the air from the sys-
tem; for instructions, see Group 60 of the
Heavy-Duty Trucks Service Manual.

If the cab stops moving while it is being raised,
do not force it to move with the tilt pump. The

06/15/93

f000131

A. Lowered (Operating) Position

B. 45-Degree-Tilt Position

C. Full-Tilt Position (80 Degrees)

Fig. 3

General Information

COE Cab Tilting, FLA/FLB: 00–11

00/20

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