BRAKE SYSTEM

H3.50-5.50XM (H70-120XM) [K005, L005]

PART NO. 1466229

1800 SRM 734

SAFETY PRECAUTIONS

MAINTENANCE AND REPAIR

• When lifting parts or assemblies, make sure all slings, chains, or cables are correctly

fastened, and that the load being lifted is balanced. Make sure the crane, cables, and
chains have the capacity to support the weight of the load.

• Do not lift heavy parts by hand, use a lifting mechanism.

• Wear safety glasses.

• DISCONNECT THE BATTERY CONNECTOR before doing any maintenance or repair

on electric lift trucks. Disconnect the battery ground cable on internal combustion lift
trucks.

• Always use correct blocks to prevent the unit from rolling or falling. See HOW TO PUT

THE LIFT TRUCK ON BLOCKS in the Operating Manual or the Periodic Mainte-
nance section.

• Keep the unit clean and the working area clean and orderly.

• Use the correct tools for the job.

• Keep the tools clean and in good condition.

• Always use HYSTER APPROVED parts when making repairs. Replacement parts

must meet or exceed the specifications of the original equipment manufacturer.

• Make sure all nuts, bolts, snap rings, and other fastening devices are removed before

using force to remove parts.

• Always fasten a DO NOT OPERATE tag to the controls of the unit when making repairs,

or if the unit needs repairs.

• Be sure to follow the WARNING and CAUTION notes in the instructions.

• Gasoline, Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG), and Diesel fuel

are flammable. Be sure to follow the necessary safety precautions when handling these
fuels and when working on these fuel systems.

• Batteries generate flammable gas when they are being charged. Keep fire and sparks

away from the area. Make sure the area is well ventilated.

NOTE: The following symbols and words indicate safety information in this
manual:

WARNING

Indicates a condition that can cause immediate death or injury!

CAUTION

Indicates a condition that can cause property damage!

Brake System

Table of Contents

TABLE OF CONTENTS

General ...............................................................................................................................................................

1

Description and Operation ................................................................................................................................

1

Brake Booster and Master Cylinder .............................................................................................................

1

Service Brake Assembly ................................................................................................................................

1

Parking Brake................................................................................................................................................

2

Brake Shoe Assemblies Repair .........................................................................................................................

2

Remove and Disassemble ..............................................................................................................................

2

Clean ..............................................................................................................................................................

3

Inspect ............................................................................................................................................................

5

Assemble and Install .....................................................................................................................................

5

Brake Booster and Master Cylinder Repair .....................................................................................................

8

Remove ...........................................................................................................................................................

8

Disassemble ...................................................................................................................................................

8

Clean and Inspect ..........................................................................................................................................

8

Assemble ........................................................................................................................................................

8

Install .............................................................................................................................................................

10

Brake Booster Filter, Replace .......................................................................................................................

11

Parking Brake Repair........................................................................................................................................

11

Remove and Disassemble ..............................................................................................................................

11

Assemble and Install .....................................................................................................................................

11

Brake System Air Removal ...............................................................................................................................

11

Brake Pedal Adjustment ...................................................................................................................................

12

Parking Brake Adjustment ...............................................................................................................................

12

Parking Brake Not Applied Switch Test...........................................................................................................

13

Parking Brake Switch Test (MONOTROL

®

Pedal Only).................................................................................

13

Brake Shoes Adjustment ...................................................................................................................................

14

Troubleshooting..................................................................................................................................................

14

This section is for the following models:

H3.50-5.50XM (H70-120XM) [K005, L005]

©2005 HYSTER COMPANY

i

"THE

QUALITY

KEEPERS"

HYSTER

APPROVED

PARTS

1800 SRM 734

Description and Operation

General

This section has a description and the repair procedures for the parts of the hydraulic brake system. These
parts include the brake booster, master cylinder, and brake shoe assemblies.

Description and Operation

The brake pedal is connected to the push rod for the
brake booster. The brake booster helps increase the
force on the master cylinder by using vacuum from
the engine. The piston in the master cylinder forces
oil to the wheel cylinders to apply the brakes. (The
system allows braking without vacuum from the en-
gine.)

1.

PUSH ROD

2.

BRAKE BOOSTER

3.

RESERVOIR

4.

MASTER
CYLINDER

5.

OUTLET
TO WHEEL
CYLINDERS

6.

ENGINE VACUUM
CONNECTION

Figure 1. Brake Booster and Master Cylinder

BRAKE BOOSTER AND MASTER
CYLINDER

The brake booster and master cylinder are assem-
bled as a unit. The brake booster has a diaphragm
that is actuated by engine vacuum. See Figure 1.
The diaphragm, along with the operator’s effort,
pushes on the piston in the master cylinder. Hy-
draulic pressure actuates the wheel cylinders as

the piston pushes fluid through the check valve. A
return spring pushes the piston back to the stop
plate when the pedal is released.

Fluid can flow

through passages in the piston and past the pri-
mary cup as the piston returns. Fluid flows across
the piston to prevent a vacuum while fluid returns
through the check valve. When the piston passes
the compensator port, excess fluid from the system
can return to the reservoir. The check valve keeps a
very small amount of pressure in the brake system.
The reservoir for brake fluid has a sending unit for
a low fluid level warning light.

SERVICE BRAKE ASSEMBLY

A service brake assembly is installed at each end of
the housing for the drive axle. Each service brake as-
sembly has a single-wheel cylinder at the top of each
back plate. The support plate has an anchor for each
shoe. When the wheel cylinder is actuated by fluid
pressure from the master cylinder, the shoes expand
against the drum. The primary shoe starts to turn
with the drum. This action pushes the secondary
shoe tight against the drum and the anchor. When
the lift truck is traveling in reverse, the primary shoe
is pushed against the anchor and the drum by the
secondary shoe.

The automatic adjusting linkage turns the adjuster
screw wheel to adjust the clearance between the
brake shoes and the brake drum.

The secondary

shoe and the links move with the drum during a
stop when the truck is traveling in reverse.

The

links permit the adjuster spring lever to rotate the
adjuster screw wheel. The adjuster screw wheel only
can turn when there is clearance between the lining
and the brake drum. The adjuster screw wheel can
be turned manually through a slot in the back plate.

1

Brake Shoe Assemblies Repair

1800 SRM 734

PARKING BRAKE

The parking brake uses the service brake shoes.
Additional linkage pushes the shoes apart when
the hand lever pulls the cables.

A switch on the

right-hand side of the mounting bracket is actuated
by the hand lever. On all units, the switch ener-
gizes the seat warning circuit when the hand lever

is released. On units with a MONOTROL

®

pedal,

this switch puts the transmission in NEUTRAL by
de-energizing the direction solenoids. On units with
a MONOTROL pedal, there is also a switch on the
left-hand side of the bracket. This switch prevents
the engine from starting unless the parking brake is
applied.

Brake Shoe Assemblies Repair

REMOVE AND DISASSEMBLE

WARNING

Brake linings can contain dangerous fibers.
Breathing the dust from these brake linings
is a cancer or lung disease hazard.

Do not

create dust!

Do not clean brake parts with

compressed air or by brushing. Use vacuum
equipment approved for brake dust or follow
the cleaning procedure in this section. When
the brake drums are removed, do not create
dust.

Do not sand, grind, chisel, hammer, or change
linings in any way that will create dust. Any
changes to linings must be done in a restricted
area with special ventilation. Protective cloth-
ing and a respirator must be used.

1.

Tilt the mast back, and put blocks under the
outer mast weldment. Tilt the mast forward to
raise the tires from the floor.

WARNING

Completely remove the air from the tires be-
fore removing them from the lift truck.

Air

pressure in the tires can cause the tire and
wheel parts to explode, causing serious injury
or death.

2.

Make sure that you remove all the air pressure
from the tires before you remove the wheels
from the hub.

Remove the wheel nuts; then

remove the wheels. Put capscrews (16 mm) in
the threaded holes to push the brake drums from
the hubs. See Figure 2 and Figure 3.

3.

Remove the capscrews that the hold the axle
shaft to the hub. Remove the axle shaft.

4.

Remove the lock nut, lock plate, and bearing ad-
justment nut from the axle housing. Remove the
outer bearing cone. Remove the hub from the
axle housing. Remove the inner seals and bear-
ing cone from the hub.

WARNING

When the brake shoes are removed, do not cre-
ate dust in the air. See the cleaning procedures
in this section.

5.

Turn the adjuster screw to loosen the brake
shoes. Disconnect the linkage for the automatic
adjuster.

6.

Use spring pliers to remove the shoe return
springs.

7.

Remove the holddown springs.

CAUTION

The adjuster screw assemblies are not the
same. Make sure that each assembly has iden-
tification for installation on the correct side of
the axle.

8.

Remove the brake shoes from the wheel cylinder
rods. Remove the adjuster screw spring. Remove
the adjuster screw assembly.

9.

Remove the parking brake cable from the lever.
Remove the lever from the brake shoe.

10. Disconnect and put a cap on the line to the wheel

cylinder. Remove the backplate and shield. Re-
move the capscrews that hold the wheel cylinder
to the backplate. Remove the cable clamp and
pull the cable through the backplate.

2

1800 SRM 734

Brake Shoe Assemblies Repair

NOTE: LEFT-HAND SIDE SHOWN.

1.

SHIELD

2.

BACKPLATE

3.

PARKING BRAKE CABLE

4.

WHEEL CYLINDER

5.

RETURN SPRING

6.

BRAKE SHOE

7.

PIVOT

8.

SPRING

9.

SPRING GUIDE

10. ADJUSTER LINK

11. PIN
12. SPRING
13. CONNECTOR
14. ADJUSTER
15. PARKING BRAKE LEVER

Figure 2. Service Brakes H3.50-4.00XMS (H70-90XM)

CLEAN

1.

Do not release brake lining dust from the brake
linings into the air when the brake drum is re-
moved.

2.

Use a solvent approved for cleaning of brake
parts to wet the brake lining dust. Follow the
instructions and cautions of the manufacturer
for the use of the solvent. If a solvent spray is
used, do not create dust with the spray.

3

Brake Shoe Assemblies Repair

1800 SRM 734

CAUTION

Do not use an oil solvent to clean the wheel
cylinder. Use a solvent approved for cleaning
of brake parts. Do not permit oil or grease in
the brake fluid or on the brake linings.

3.

When the dust is wet, clean the parts. Put any
cloth or towels in a plastic bag or an airtight con-
tainer while they are still wet. Put a DANGER-
OUS FIBERS warning label on the plastic bag or
airtight container.

NOTE: LEFT-HAND SIDE SHOWN.

1.

SHIELD

2.

BACKPLATE

3.

PARKING BRAKE CABLE

4.

WHEEL CYLINDER

5.

LINK

6.

RETURN SPRING

7.

BRAKE SHOE

8.

WASHER

9.

RETAINER

10. SPRING GUIDE
11. PIN
12. SPRING
13. LINK PIVOT
14. SPRING LINK

15. CONNECTOR
16. ADJUSTER SPRING
17. ADJUSTER LEVER
18. ADJUSTER
19. PARKING BRAKE LEVER

Figure 3. Service Brakes H4.00XM-5.50XM (H100-120XM)

4

1800 SRM 734

Brake Shoe Assemblies Repair

4.

Any cleaning cloths that will be washed must be
cleaned so that fibers are not released into the
air.

INSPECT

WARNING

Cleaning solvents can be flammable and toxic
and can cause skin irritation.

When using

cleaning solvents, always follow the recom-
mendations of the manufacturer.

1.

Clean all metal parts except the linings and the
wheel cylinder with solvent.

2.

Check the bore of the wheel cylinder for holes or
scratches. Replace the wheel cylinder if there is
any damage.

3.

Check the return springs for damage. Inspect the
backplate for wear where the brake shoes touch
the backplate.

4.

Inspect the brake shoes for cracks or damage. If
the linings or shoes are worn or damaged, replace
the brake shoes. It is recommended that brake
shoes be replaced in complete sets.

5.

Check the adjuster screw wheel for wear. Make
sure the adjuster screw turns. Check for bent or
broken adjuster links.

WARNING

The brake shoes on both wheels must be re-
placed if any shoe is damaged. The brake per-
formance on both ends of an axle must be equal
or the lift truck can be difficult to steer when
the brakes are applied.

NOTE: If the brake drums require grinding, do not
grind more than 1.5 mm (0.060 in.) from the diam-
eter. The maximum inside diameter of the brake
drum, including wear, is 319.5 mm (12.58 in.). If
the brake drum is larger than this, replace the brake
drum.

6.

Inspect the brake drums for cracks or damage.
Use sandpaper to clean the surface for the brake
shoes.

ASSEMBLE AND INSTALL

1.

Install the wheel cylinder on the backplate. Push
the parking cable through the backplate and fas-
ten the clamp. See Figure 2 and Figure 3.

2.

Use a sealant (Hyster Part No. 264159) between
the backplate and the axle hanger. Install the
shield and backplate. Using the sequence shown
in Figure 4, tighten the capscrews to 340 to
375 N•m (250 to 275 lbf ft).

Figure 4. Backplate Installation

3.

Connect the brake line to the fitting on the wheel
cylinder.

4.

Install the link pivot on the rear shoe. Install
the parking brake lever on the front shoe. Install
the anchor pins in the support flange so that they
engage the brake shoes.

5.

Lubricate the back plate with a small amount of
grease where the brake shoes touch. Install the
brake shoes on the anchor and engage the push
rods of the wheel cylinder. Engage the parking
brake lever in the slot in the parking brake cable
as the brake shoes are installed on the back plate.

6.

Put an anchor pin that holds the brake shoes
through the back plate. Put a spring seat, spring,
and retainer on the anchor pin. Push the retainer
onto the anchor pin and rotate the retainer 90
degrees. Make sure the retainer is in the correct
position. Install another retainer spring assem-
bly.

7.

Install the link, parking brake, and spring be-
tween the parking brake lever and the brake
shoe.

8.

H4.00XM-5.50XM (H100-120XM): Using the
correct tools, install the return springs.

9.

H3.50-4.00XMS (H70-90XM): Install the anchor
guide on the anchor. Install the pivot plate on its
anchor.

5

Brake Shoe Assemblies Repair

1800 SRM 734

10. H3.50-4.00XMS (H70-90XM): Lubricate the

adjuster cable where it slides in the pivot plate
groove.

11. H3.50-4.00XMS (H70-90XM): Fasten the link to

the adjuster wheel actuator and put the cable
around the pivot plate. Raise the adjuster wheel
actuator against the spring tension and connect
the link to the anchor.

CAUTION

Be sure to install the white return spring first
and then the black return spring. See Figure 5.
Improper assembly can result in brake failure
and/or component damage.

12. H3.50-4.00XMS (H70-90XM): Using the correct

tools, install the return springs as follows:

a. Install the white spring.

b. Install the black spring.

13. H3.50-4.00XMS (H70-90XM): Verify that the re-

turn springs are properly installed as shown in
Figure 5.

14. Connect the cable for the parking brake to the

lever.

Figure 5. Proper Installation of Return Springs

6

1800 SRM 734

Brake Shoe Assemblies Repair

Legend for Figure 5

NOTE: H3.50-4.00XMS (H70-90XM) RETURN SPRINGS SHOWN.

1.

WHITE SPRING

2.

BLACK SPRING

WARNING

The threads of the adjuster wheel are not the
same for each side. If the adjuster assemblies
are installed on the wrong side, the brake shoe
clearance will increase each time the brakes
are applied. The adjuster wheel for the right
brake has right-hand threads.

The adjuster

wheel for the left brake has left-hand threads.

15. Lubricate the adjuster screw with antiseize com-

pound. Turn the adjuster screw in so that the
brake shoes retract. Install the adjuster between
the shoes. Align the adjuster screw wheel with
the slot in the backplate. Install the adjuster
spring with the long hook toward the adjuster
screw wheel.

16. H4.00XM-5.50XM (H100-120XM): Install the

adjuster spring lever and the two links.

CAUTION

Do not damage the seals when you install the
hub assembly.

17. Use new oil seals. Install the inner seal, the bear-

ing cups, and the outer seal in the hub. Install
the inner bearing cone on the spindle. Lubricate
the inner bearing with grease. See Figure 6.

18. Install the hub on the spindle. See Figure 6. Lu-

bricate the outer bearing cone with 80W-90 oil for
gears. Install the outer bearing cone and the ad-
justment nut. Tighten the adjustment nut to 200
to 225 N•m (148 to 166 lbf ft) while you rotate the
hub. Loosen the nut until the hub rotates freely
with NO end play. The torque must be less than
27 N•m (20 lbf ft). Tighten the nut to 34 N•m
(25 lbf ft) or to the first alignment position after
34 N•m (25 lbf ft). Install the lockwasher to hold
the nut. Install the lock nut and tighten it to 135
to 150 N•m (100 to 111 lbf ft).

19. Install the brake drum and adjust the brake

shoes as described in Brake Shoes Adjustment.

1.

AXLE SHAFT

2.

LOCK NUT

3.

LOCK PLATE

4.

LOCK NUT

5.

OUTER BEARING

6.

HUB ASSEMBLY

7.

BEARING CUP

8.

INNER SEAL

9.

BEARING CUP

10. INNER BEARING
11. OUTER SEAL
12. BRAKE DRUM
13. SHIELD
14. PARKING BRAKE

CABLE

Figure 6. Brake and Hub Assembly

20. Apply sealant (Hyster Part Number 264159) to

the flange of the axle shaft. Install the axle shaft.
Tighten the capscrews to 225 to 250 N•m (166 to
184 lbf ft). See Figure 7.

CAUTION

When the wheels have been installed, check
all wheel nuts after 2 to 5 hours of operation.
Tighten the nuts to the correct torque. When
the nuts stay tight after an 8-hour check, the
interval for checking can be extended to 500
hours.

21. Install the wheel. Tighten the wheel nuts to 610

to 680 N•m (450 to 500 lbf ft) on all units.

7

Brake Booster and Master Cylinder Repair

1800 SRM 734

22. Remove the air from the brake system and adjust

the brakes. See Brake Shoes Adjustment in this
section.

Figure 7. Axle Shaft Tightening Sequence

Brake Booster and Master Cylinder Repair

REMOVE

1.

Disconnect the push rod from the brake pedal.
See Figure 8. Disconnect the brake line at the
master cylinder. Cover the end of the brake line.
Disconnect the wires at the reservoir.

2.

Remove the nuts that hold the brake booster to
the mount.

3.

Remove the brake booster and master cylinder.

DISASSEMBLE

NOTE: Do not disassemble the brake booster. Repair
parts are not available.

1.

Remove the nuts that hold the master cylinder to
the brake booster. See Figure 9.

WARNING

There is a compressed spring behind the pis-
ton. Be careful when removing the snap ring
and piston.

2.

Remove the snap ring from the end of the master
cylinder. Carefully remove the piston and spring
from the bore.

3.

Remove seals from the piston.

CLEAN AND INSPECT

CAUTION

DO NOT use an oil solvent to clean the master
cylinder. Use a solvent approved for cleaning
of brake parts.

Inspect the bore of the master cylinder for holes or
scratches. Replace the master cylinder assembly if
there is damage.

ASSEMBLE

NOTE: Lubricate the parts of the master cylinder
with clean brake fluid.

1.

Install the seals on the piston. Install the seat,
check valve, and spring in the bore. Install the
spring and piston. Install the snap ring in the
bore. See Figure 9.

2.

Install the O-ring and master cylinder on the
brake booster.

8

1800 SRM 734

Brake Booster and Master Cylinder Repair

1.

RETURN SPRING

2.

BRAKE PEDAL

3.

INCHING SPOOL LINK

4.

INCHING LINK

5.

INCHING CRANK

6.

BRAKE BOOSTER/MASTER CYLINDER

7.

BRAKE SWITCH

8.

BRACKET

Figure 8. Brake System Arrangement

9

Brake Booster and Master Cylinder Repair

1800 SRM 734

1.

BRAKE BOOSTER

2.

SNAP RING

3.

SEAL

4.

PISTON

5.

SPRING

6.

CHECK VALVE

7.

SEAT

8.

O-RING

9.

MASTER CYLINDER

10. GROMMET
11. RESERVOIR
12. CAP
13. PIN
14. VACUUM FITTING
15. VACUUM LINES
16. CLAMPS
17. BRAKE BOOSTER FILTER
18. VACUUM LINE FITTING

Figure 9. Brake Booster and Master Cylinder

INSTALL

1.

Put the master cylinder in position on the brake
booster and install the nuts for the master cylin-
der. Install the brake booster on the mount. In-
stall the nuts for the brake booster. Connect the
push rod to the brake pedal. See Figure 8.

2.

Connect the brake line at the master cylinder.
Connect the wires at the reservoir. Fill the reser-
voir and remove the air from the brake system as
described in Brake System Air Removal in this
section.

3.

Adjust the brake linkage as described in Brake
Pedal Adjustment.

10

1800 SRM 734

Brake System Air Removal

BRAKE BOOSTER FILTER, REPLACE

1.

Remove the two clamps holding the old filter
to the brake vacuum lines. Remove the brake
booster filter. See Figure 9.

2.

Install new filter onto brake vacuum lines. In-
stall the two clamps to hold brake booster filter
onto brake vacuum lines.

Parking Brake Repair

REMOVE AND DISASSEMBLE

If the lever assembly for the parking brake must be
removed from the cowl, use the following procedure
(see Figure 10):

1.

Use blocks next to the tires to make sure the lift
truck cannot move. Release the parking brake
lever.

2.

Remove the four nuts, bolts, and washers that
fasten the bracket for the parking brake to the
cowl. Disconnect the wires at the switches. Re-
move the bracket and brake lever assembly.

3.

Loosen the jam nuts that fasten the threaded
ends of the brake cables to the brake lever as-
sembly.

4.

Turn the adjuster knob counterclockwise until
the brake cables are loosened. Disconnect the ca-
bles from the link.

5.

The service brake assembly must be removed be-
fore the parking brake cable can be removed from
the backplate of the service brake. A snap ring
holds the sheath of the parking brake cable in
the backplate of the service brake. Remove the
snap ring and remove the parking brake cable
from the backplate.

ASSEMBLE AND INSTALL

On the H3.50-4.00XMS (H70-90XM) units, the park-
ing brake cables must be installed in the backplate
before the service brake is installed. A snap ring
holds the sheath of the parking brake cable in the
backplate of the service brake. Install the parking
brake cable in the backplate and install the snap ring
that holds the sheath of the parking brake cable in
the backplate.

If the lever assembly for the parking brake was re-
moved from the cowl, use the following procedure for
installation (see Figure 10):

1.

Make sure the parking brake lever is in the re-
leased position. Turn the adjustment knob until
the link is adjusted to the bottom of the adjust-
ment slot.

2.

Adjust the jam nuts on the ends of the cable as-
semblies so that the threads of the cable sheaths
extend 6 mm (0.25 in.) above their support plate
in the lever assembly.

3.

Install the round ends of the parking brake ca-
bles in their slots in the link. Tighten the upper
jam nuts to hold the sheaths of the parking brake
cables in their support.

4.

Use the four capscrews, washers, and nuts and
fasten the bracket to the inside of the cowl.

Brake System Air Removal

The air must be removed from the brake fluid. Fill
the reservoir for the master cylinder with brake fluid.
Always remove the air from the master cylinder first,
then the wheel cylinders. Put one end of a rubber
hose on the special fitting at the master cylinder or
the wheel cylinders. Put the other end of the hose in a

container with brake fluid. Loosen the special fitting.
Push slowly on the brake pedal. Close the special
fitting. Repeat the procedure until no air bubbles
are seen in the container. Check the fluid level in
the reservoir. Keep the reservoir full of brake fluid
during these procedures.

11

Parking Brake Adjustment

1800 SRM 734

Brake Pedal Adjustment

NOTE: The adjustment for the brake/inching pedal is in the section Single-Speed Powershift Transmission,
Troubleshooting and Repair 1300 SRM 752 or Two-Speed Powershift Transmission, Troubleshooting
and Repairs 1300 SRM 728.

Parking Brake Adjustment

Make sure that the service brakes are adjusted and
the operation of the automatic adjuster mechanism
is correct before the parking brake is adjusted.

1.

Turn the adjustment knob to raise the link and
tighten the parking brake cables. Turn the ad-
justment knob until the parking brakes are fully
applied when the lever is used to apply the park-
ing brake. See Figure 10.

2.

Test the operation of the parking brake. The lift
truck with a capacity load must not move when
the parking brake is applied on a 15% grade [a
slope that increases 1.5 m in 10 m (1.5 ft in 10 ft)].

3.

Check the operation of the switches on the park-
ing brake.

1.

SWITCH

2.

PARKING BRAKE
LEVER

3.

ADJUSTMENT
KNOB

4.

ADJUSTMENT
SLOT

5.

EQUALIZER LINK

6.

PARKING BRAKE
CABLES

7.

NUTS

8.

COWL

Figure 10. Parking Brake Lever Adjustment

12

1800 SRM 734

Parking Brake Switch Test (MONOTROL

®

Pedal Only)

Parking Brake Not Applied Switch Test

The Parking Brake Not Applied switch is located in the operator seat. This switch actuates an audible buzzer
on the instrument cluster. When the operator leaves the seat for more than two seconds without applying the
parking brake, the buzzer will be on continuously for 10 seconds. The buzzer operates whether the key switch
is ON or OFF.

Parking Brake Switch Test (MONOTROL

®

Pedal Only)

When the parking brake assembly and cables have
been adjusted, the parking brake switches must be
tested for correct operation.

WARNING

If the brake switches are not adjusted cor-
rectly, the engine can be started with the
parking brake released.

The purpose of the

left-hand switch (MONOTROL only) is to pre-
vent the starter motor from being energized
when the parking brake is not applied. The
right-hand switch de-energizes the direction
solenoids to put the transmission in Neutral
(MONOTROL only) when the parking brake is
applied.

1.

Put the lift truck on blocks so that the drive
wheels do not touch the ground or any other
object. Put blocks at both sides of the steering
tires to prevent movement of the lift truck.

2.

Release the parking brake. The right-hand, two-
circuit microswitch closes the electric circuit for
the MONOTROL pedal (energizes the solenoids
for the powershift transmission). The left-hand
switch de-energizes the starting circuit.

3.

Turn the ignition switch to the START position.
If the parking brake switch operates correctly,

the starter will not energize. Turn the ignition
switch to the OFF position.

4.

Apply the parking brake with the parking brake
lever. The right-hand, two-circuit microswitch
opens the MONOTROL circuit (de-energize the
solenoids for the transmission). The starting cir-
cuit is energized by the ignition switch through
the left-hand switch.

5.

Turn the ignition switch to the START position.
The starter operates when the parking brake
switch operates correctly.

Turn the ignition

switch to the OFF position.

6.

Check the wires for the parking brake switches if
the conditions from the results of Step 2 through
Step 5 are not correct.

7.

Apply the parking brake and start the engine.
Push the parking brake lever toward the re-
leased position, but do not push the release
button. The parking brake will stay in the ON
position and locked. The transmission must be
in NEUTRAL any time the parking brake lever
is applied. If the results of the test are not cor-
rect, check for wear and damage. Make repairs
as necessary and repeat Step 1 through Step 7.

13

Troubleshooting

1800 SRM 734

Brake Shoes Adjustment

The brake shoes are automatically adjusted when the
brakes are applied while the truck travels in reverse.
Use the procedure that follows to manually adjust
the brakes after you make repairs.

NOTE: If the automatic brake adjusters adjust the
brake shoes too much or too little, refer to Assemble
and Install in this section for the brake shoes.

1.

Put the lift truck on blocks so that the drive
wheels do not touch the ground. See the section
Periodic Maintenance 8000 SRM 737 for the
correct procedures. Make sure that the blocks
do not prevent access to the backplates of the
brakes.

2.

Remove the plugs in the slots in the backplates.

3.

Use a tool for brake adjustment in the slot near-
est the teeth of the adjuster screw wheel. Push
up on the teeth and turn the adjuster screw wheel
until the brake shoes touch the brake drum.

4.

Put a small screwdriver through the slot in the
backplate. Move the automatic adjustment lever
away from the adjuster screw wheel.

5.

Turn the adjuster screw wheel with the tool for
brake adjustment. Push down on the teeth to
turn the adjuster screw wheel in the opposite
direction. Turn the adjuster screw wheel 1 1/2
revolutions for the necessary clearance between
the brake shoes and the drum. Rotate the drive
wheel to check for clearance.

6.

Repeat Step 3, Step 4, and Step 5 at the other
brake assembly. Install the plugs in the back-
plates.

7.

Remove the lift truck from the blocks. Drive the
lift truck in forward and reverse. Use the brakes
to stop ten times in each direction.

Troubleshooting

PROBLEM

POSSIBLE CAUSE

PROCEDURE OR ACTION

The brakes do not stop the
lift truck correctly.

Air is in the brake system.

Remove air from brake system.

The mount for the brake booster or
the brake booster is loose.

Tighten the capscrews.

The brake shoes are worn or dam-
aged.

Install new brake shoes.

The linings are too hard.

Install new brake shoes.

A brake drum is cracked.

Install new brake drum.

A backplate is damaged.

Install new backplate.

A wheel cylinder is leaking or does
not operate correctly.

Repair or install a new wheel cylin-
der.

The brake linings do not fit the brake
drums.

Install new brake shoes.

The master cylinder is damaged.

Repair or install a new master cylin-
der.

14

1800 SRM 734

Troubleshooting

PROBLEM

POSSIBLE CAUSE

PROCEDURE OR ACTION

The brakes do not stop the
lift truck correctly. (Cont.)

Water or oil is on the brake linings.

Clean linings or install new brake
shoes.

The brake booster is damaged.

Install a new brake booster.

One brake does not release.

A brake shoe is damaged.

Install new brake shoes.

A return spring is damaged.

Install a new spring.

The brake lines have a restriction.

Install new brake lines.

A parking brake cable is damaged or
needs adjustment.

Adjust or install new brake cable(s).

The wheel cylinder is damaged.

Repair or install a new wheel cylin-
der.

The backplate is worn or damaged.

Install a new backplate.

The brakes make too much
noise.

Oil, water, or brake fluid is on the lin-
ings.

Clean linings or install new brake
shoes.

The brake linings or brake shoes are
worn or damaged.

Install new brake shoes.

The brake drum is damaged.

Install a new brake drum.

The brakes do not operate
equally.

Oil or brake fluid is on the linings.

Clean linings or install new brake
shoes.

The linings are worn or hard.

Install new brake shoes.

A wheel cylinder is leaking.

Repair or install a new wheel cylin-
der.

The brake shoes are not correctly in-
stalled.

Install brake shoes.

The backplate or brake shoes are
damaged.

Install new parts.

The brake drum is not round.

Repair or install a new brake drum.

The shoes are adjusted too tight.

Adjust brake shoes correctly.

15

Troubleshooting

1800 SRM 734

PROBLEM

POSSIBLE CAUSE

PROCEDURE OR ACTION

Both brakes do not release.

The parking brake is not released.

Adjust parking brake.

The parking brake cables need ad-
justment.

Adjust parking brake.

There is not enough clearance for the
push rod.

Adjust brake linkage.

The master cylinder is damaged.

Repair or install a new master cylin-
der.

The brake shoes are adjusted too
tightly.

Adjust brake shoes.

The parking brake will not
hold the lift truck.

Oil, water, or brake fluid is on the lin-
ings.

Clean linings or install new brake
shoes.

The parking brake cables need ad-
justment.

Adjust parking brake.

The parking brake cable is damaged.

Install new cable.

The parking brake will not
release.

The parking brake lever is adjusted
too tightly.

Adjust parking brake.

The parking brake cables are dam-
aged.

Install new cable(s).

16

TECHNICAL PUBLICATIONS

1800 SRM 734

5/05 (3/04)(9/03)(8/02)(8/99) Printed in United Kingdom