The document provides repair procedures for wet disc brakes on a drive unit. It describes removing and inspecting the brake discs and installing new discs as a pack if thickness is less than 0.91 inches. Discs must be installed with notches aligned and springs replaced when replacing the disc pack. The aluminum reaction disc is replaced if thickness is 0.18 inches or less.

1. ERP040-060DH (E216)
SERVICE MANUAL CONTENTS
SECTION
PART
NUMBER
YRM
NUMBER
REV
DATE
FRAME............................................................................................................................ 524256685 0100 YRM 1222 05/06
DC MOTOR MAINTENANCE.......................................................................................... 524158039 0620 YRM 0294 03/08
AC MOTOR MAINTENANCE.......................................................................................... 524183080 0620 YRM 1053 03/10
DRIVE AXLE WET BRAKE............................................................................................ 524256686 1400 YRM 1223 03/09
STEERING AXLE............................................................................................................ 524158752 1600 YRM 0316 08/06
STEERING CONTROL UNIT.......................................................................................... 524158753 1600 YRM 0720 11/06
STEERING SYSTEM...................................................................................................... 524183081 1600 YRM 1054 11/06
BRAKE PEDAL AND LINKAGE..................................................................................... 524264587 1800 YRM 1253 09/06
HYDRAULIC SYSTEM.................................................................................................... 524179945 1900 YRM 0559 04/09
MAIN CONTROL VALVE................................................................................................ 524179946 2000 YRM 0562 02/09
MAIN CONTROL VALVE E-CONTROLS....................................................................... 524256687 2000 YRM 1224 04/08
CYLINDER REPAIR (MAST S/N A551, A555, A559, A661, A662, A663, A66, B507,
B508, B509, B551, B555, B559, B562, B563, B564, B661, B662, B663, C515,
C551, C555, C559, D507, D508, D509, D515, D562, D563, D564, E509, AND
E564).......................................................................................................................... 524223768 2100 YRM 1139 02/14
ELECTRICAL SYSTEM.................................................................................................. 524183082 2200 YRM 1055 10/09
AC MOTOR CONTROLLER DESC/CHKS/ADJ/TRBSHT/REP&THEORY OF
OPERATION/DISPLAY PANEL................................................................................. 524183083 2200 YRM 1056 03/09
TROUBLESHOOTING AND ADJUSTMENTS USING THE AC CONTROLS
PROGRAM................................................................................................................. 524183085 2200 YRM 1058 04/11
INDUSTRIAL BATTERY................................................................................................. 524158040 2240 YRM 0001 09/14
MAST - DESCRIPTION................................................................................................... 524158890 4000 YRM 0521 03/06
MAST REPAIRS (S/N A551, A555, A559, A661, A662, A663, A664, B507, B508,
B509, B551, B555, B559, B562, B563, B564, B661, B662, B663, C515, C551,
C555, C559, D507, D508, D509, D515, D562, D563, D564, E509, AND E564)........ 524223776 4000 YRM 1148 02/14
METRIC AND INCH (SAE) FASTENERS....................................................................... 524150797 8000 YRM 0231 10/13
DIAGRAMS..................................................................................................................... 524256688 8000 YRM 1225 05/06
PERIODIC MAINTENANCE............................................................................................ 524256689 8000 YRM 1226 08/08
CAPACITIES AND SPECIFICATIONS........................................................................... 524256690 8000 YRM 1227 05/06
PART NO. 524256684 (09/14)

2. 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 Maintenance 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 YALE 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 hazardous situation which, if not avoided, could result in death or
serious injury.
CAUTION
Indicates a hazardous situation which, if not avoided, could result in minor
or moderate injury and property damage.
On the lift truck, the WARNING symbol and word are on orange background.
The CAUTION symbol and word are on yellow background.

3. Drive Unit Assembly Table of Contents
TABLE OF CONTENTS
General................................................................................................................................................................ 1
Description .......................................................................................................................................................... 1
Wet Disc Brake Repair ........................................................................................................................................ 5
Wet Disc Brakes.............................................................................................................................................. 5
Remove....................................................................................................................................................... 5
Inspect ........................................................................................................................................................ 9
Install .......................................................................................................................................................... 9
Gearbox Replacement......................................................................................................................................... 14
Remove........................................................................................................................................................... 14
Gearbox Removal ....................................................................................................................................... 14
Intermediate Flange Removal..................................................................................................................... 15
Disassemble.................................................................................................................................................... 17
Intermediate Flange.................................................................................................................................... 17
Assemble ........................................................................................................................................................ 25
Intermediate Flange.................................................................................................................................... 25
Install............................................................................................................................................................... 38
Intermediate Flange Installation.................................................................................................................. 38
Gearbox Installation.................................................................................................................................... 40
Drive Unit Removal.............................................................................................................................................. 42
Main Housing Repair........................................................................................................................................... 46
Main Housing, Right-Hand Side...................................................................................................................... 46
Remove....................................................................................................................................................... 46
Disassemble ............................................................................................................................................... 47
Clean and Inspect....................................................................................................................................... 48
Assemble .................................................................................................................................................... 49
Install .......................................................................................................................................................... 49
Main Housing, Left-Hand Side ........................................................................................................................ 50
Remove....................................................................................................................................................... 50
Disassemble ............................................................................................................................................... 51
Clean and Inspect....................................................................................................................................... 52
Assemble .................................................................................................................................................... 52
Install .......................................................................................................................................................... 52
Differential Assembly Replacement..................................................................................................................... 53
Remove........................................................................................................................................................... 53
Install............................................................................................................................................................... 53
Traction Motor Repair .......................................................................................................................................... 54
Remove........................................................................................................................................................... 54
Disassemble.................................................................................................................................................... 54
Assemble ........................................................................................................................................................ 57
Install............................................................................................................................................................... 57
Drive Unit Installation........................................................................................................................................... 58
Torque Specifications .......................................................................................................................................... 59
Troubleshooting ................................................................................................................................................... 60
This section is for the following models:
ERP20-30ALF (ERP040-060DH) [E216]
©2009 Yale Materials Handling Corp. i

4. 1400 YRM 1223 Description
General
This section has the description and repair procedures for the differential, drive axle, traction motor, and the wet disc
brakes.
Description
The drive unit consists of following main components
(see Figure 1):
• The traction motor with hollow shaft.
• Mechanical differential assembly (located on
left-hand side of traction motor shaft).
• The gearbox with intermediate flange, containing the
wet disc brakes.
• Main housings, containing the pistons for the wet disc
brakes and the parking brake levers.
• Speed sensor and reluctor wheel (located on traction
motor shaft, see Figure 8).
1. WHEEL HUB
2. GEARBOX (LH)
3. INTERMEDIATE FLANGE (LH)
4. MAIN HOUSING (LH)
5. PARKING BRAKE LEVER
6. TRACTION MOTOR
7. MAIN HOUSING (RH)
8. INTERMEDIATE FLANGE (RH)
9. GEARBOX (RH)
10. SPEED SENSOR
11. DIFFERENTIAL ASSEMBLY
Figure 1. Drive Unit
1

5. Description 1400 YRM 1223
The drive unit assembly is fastened to the frame of the
lift truck by the frame mounts of the main housings. See
Figure 2.
The mast is mounted on the J-hook mountings of the
main housings of the drive unit. See Figure 3.
The traction motor is mounted in between the two main
housings. The traction motor generates the power to
the differential assembly. See Figure 4.
1. FRAME MOUNTS
Figure 2. Drive Unit Frame Mounts
2

6. 1400 YRM 1223 Description
1. J-HOOK MOUNTINGS
Figure 3. Mast Mounting Hooks
1. WHEEL HUB
2. PLANETARY GEAR
3. INPUT SHAFT (RH)
4. DRIVE GEAR
5. AXLE SHAFT
6. TRACTION MOTOR SHAFT
7. DIFFERENTIAL ASSEMBLY
8. DRIVE GEAR
9. INPUT SHAFT (LH)
10. SUN PINION
11. DRIVEN GEAR
12. BRAKE DISC PACK
13. DISC PUSHER
14. PISTON
15. PARK BRAKE LEVER
Figure 4. Drive Unit
3

7. Description 1400 YRM 1223
The differential then transfers the power through the
axle shaft to the input shafts located in the intermediate
flange assemblies. The input shaft drive gears transfer
the power to the driven gears. The driven gears then
transfer the power to the sun pinion. See Figure 5.
1. DRIVE GEAR
2. INTERMEDIATE FLANGE
3. INPUT SHAFT
4. AXLE SHAFT
5. DRIVEN GEAR
6. SUN PINION
Figure 5. Drive Gear, Driven Gear, and Sun Pinion
The sun pinion then transfers the power to the plane-
tary gears and planetary carrier which then engages the
wheel hubs. See Figure 6.
The wet brake discs are mounted on the intermediate
flanges. The piston, which is located in the main hous-
ing (one in each main housing), is activated when the
brake pedal is applied. The piston presses against the
disc pusher which compresses the brake friction discs
and steel discs which causes the braking. See Figure 7.
1. PLANETARY CARRIER
2. PLANETARY GEARS
3. RING GEAR
4. WHEEL HUB
Figure 6. Planetary Gears
1. INTERMEDIATE FLANGE
2. DISC PUSHER
3. BRAKE DISC PACK
Figure 7. Brake Disc Pack
4

8. 1400 YRM 1223 Wet Disc Brake Repair
The parking brake levers press against the back of the
piston which forces the piston to press against the disc
pusher to compress the brakes friction discs and steel
discs to mechanically apply the parking brake.
The speed sensor is mounted on the main housing on
the right-hand side of the drive unit. The reluctor wheel
is mounted on the traction motor shaft on the right-hand
side of the traction motor. The speed sensor is a hall
effect sensor which reads the variation in its magnetic
field when a tooth of the reluctor wheel passes the sen-
sor. See Figure 8.
1. SPEED SENSOR
2. RELUCTOR WHEEL
Figure 8. Speed Sensor and Reluctor Wheel
Wet Disc Brake Repair
WET DISC BRAKES
For replacement of the pistons and piston seals, refer
to the section Main Housing Repair.
Remove
STEP 1.
Remove the gearbox. Refer to the section Gearbox Replacement.
STEP 2.
Press down on the disc pusher device and remove the
retaining rings from the studs.
5

9. Wet Disc Brake Repair 1400 YRM 1223
STEP 3.
Remove the disc pusher device from the studs.
1. DISC PUSHER DEVICE
2. STUDS
STEP 4.
Remove the springs from the studs.
If necessary, remove the studs.
6

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11. 1400 YRM 1223 Wet Disc Brake Repair
1. STUDS
2. SPRINGS
STEP 5.
Note the position of the notches on the steel discs for
correct positioning during assembly.
Remove one steel disc.
1. STEEL DISC
2. NOTCH
7

12. Wet Disc Brake Repair 1400 YRM 1223
STEP 6.
Remove the one friction disc.
1. FRICTION DISC
STEP 7.
Remove four springs/spacers.
1. SPRINGS/SPACERS
8

13. 1400 YRM 1223 Wet Disc Brake Repair
STEP 8.
Repeat STEP 5 through STEP 7 until the last steel disc is removed.
STEP 9.
Remove the aluminum reaction disc.
Inspect
1. Inspect the brake friction discs and brake steel
discs. The discs must be measured as a pack
(6 steel discs and 5 friction discs) to determine if
the discs need replaced. Replace discs as a pack
when the thickness is less than 23 mm (0.91 in.).
A new disc pack will have a thickness of 23.95 to
24.45 mm (0.94 to 0.96 in.). When replacing the
disc pack, all springs must also be replaced.
2. Inspect the aluminum reaction disc. Replace the
aluminum reaction disc when the thickness is equal
or less than 4.5 mm (0.18 in.). A new aluminum re-
action disc will have a thickness of 4.95 to 5.05 mm
(0.195 to 0.199 in.).
Install
STEP 1.
If removed, install the four pins.
9

14. Wet Disc Brake Repair 1400 YRM 1223
STEP 2.
If removed, apply Loctite®
242 to the studs and install
the studs. Tighten the studs to 2 N•m (17.7 lbf in).
STEP 3.
Install the aluminum reaction disc.
NOTE: The first and last disc installed must be a smooth steel disc.
STEP 4.
Align the notch of the steel disc as noted during disas-
sembly.
Install one steel disc.
1. NOTCH
10