PDF Service Repair Manual JCB Vibromax 752C Tandem Drum Roller - 653 KB
This is the complete service and repair manual for the JCB Vibromax 752C tandem drum roller.
It stands as an indispensable resource for mechanics, containing highly detailed instructions for all maintenance and repair procedures.
With this comprehensive manual, you can confidently tackle everything from routine servicing to major overhauls of the engine, hydraulics, and critical vibratory systems, ensuring your roller meets compaction specifications.
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TANDEM DRUM ROLLER
SERVICE MANUAL SM71001
May 2000
Model 752C
--- Page 3 ---
SM71001 - SECTION ONE GENERAL INFORMATION
MACHINE SERIAL NUMBERS
Enter the machine and component serial numbers highlighted in the above drawing. When
ordering spare parts or requesting information on the machine, have these numbers avail-
able for your dealer. Make a copy of these numbers and keep it in a safe place. If the
machine is stolen, these numbers should be made available to the investigating authorities.
1 Model / Serial Number
2 Engine Serial Number
3 ROPS Serial Number
4 Front Drive Motor Serial Number
5 Rear Drive Motor Serial Number
6 Drive Pump Serial Number
7 Vibration Pump Serial Number
5/21/2000 1-5
--- Page 4 ---
SM71001 - SECTION ONE GENERAL INFORMATION
ROLLOVER PROTECTION STRUCTURE
There are 16 bolts, nuts, and washers (4 each post) that hold the ROPS to the machine. The bolts
are located at the base of each leg of the ROPS. The torque specifications for each bolt is 195 foot
pounds (265 Nm.).
5/21/2000 1 - 15
--- Page 5 ---
SECTION TWO
ENGINE
5/21/2000 2-1
--- Page 6 ---
SM71001 - SECTION THREE ELECTRICAL
S3 HORN SWITCH: Push this switch to sound the horn
NOTE: You will hear a warning sound from the horn if the engine temperature is too high.
You will also hear a warning sound from the horn if the propulsion system is engaged
while the parking brake is on.
S13 HEAD & TAIL LIGHT SWITCH: This is a three position rotary switch: “OFF”, “LOW BEAM”,
and “HIGH BEAM”.
S4 TURN SIGNAL SWITCH: This is a three position rotary switch. “OFF” is in the center position.
“LEFT” and “RIGHT” turn correspond to the direction the switch is rotated.
S14 BACKUP LIGHT SWITCH: This switch controls the backup lights. Push the button in to the
“ON” position to illuminate the backup lights. The switch button will illuminate and lock into the
“ON” position until the button is pushed again to release the switch.
5/21/2000 3-3
--- Page 7 ---
SM71001 - SECTION THREE ELECTRICAL
D Delay relay Other items which may help you understand
the diagram:
E Element (headlight, tail lights, panel
lights, etc.) All drawings are shown without power
F Fuse All components are shown in the OFF position
G Battery, alternator All relay contacts #87 are normally open
contacts
H Indicator (panel indicator light, horn,
alarm) All relay contacts #87a are normally closed
contacts
K Relay
Relay terminal #30 is power to the contacts
M Motor (when possible)
P Gauges (hour meter, temperature Relay terminal #87 or #87a is power from the
gauge, etc.) contacts (when possible)
R Resistor Power to control the relay is always terminal
#86
S Switch
Ground is always terminal #85
V Diode
X Connector
Y Solenoid control valve
An identification chart on the diagram lists each
component, the component description and its
location on the diagram by line number.
The layout of all Vibromax electrical diagrams
is similar in regards to the location of
components. The battery will always be located
on line 1, starter on line 2, alternator on line 3,
etc. Slight variations can be seen on different
models, but the major components will be
located in the same general area of the
diagram. This similar layout makes locating
components easier as you become more
familiar with the drawings.
5/21/2000 3 - 13
--- Page 8 ---
SM71001 - SECTION THREE ELECTRICAL
STARTER SOLENOID When the plunger (3) moves to full stroke
and the drive pinion is fully engaged, the so-
A starter solenoid has two coils. They are lenoid contacts (5) are closed, allowing full
the “hold-in coil” (1) which connects to power to the starter motor.
ground, and the “closing coil” (2) which is
connected to ground through the starter
motor windings.
When the switch is “ON”, current passes STARTER SYSTEM DIAGNOSTICS
through the hold-in coil (1), creating a mag-
netic field around the plunger (3). Current SOLENOID CIRCUIT TEST
also passes through the closing coil (2),
creating a second field. CAUTION: Fasten the manual shut off le-
ver on the injection pump in the "OFF"
The current that flows from the closing coil position prior to this test.
into the starter motor windings causes the
motor to rotate slowly. The combined mag- Connect a test light or voltmeter to test point
netic fields of the two coils causes the (1) and the other lead to a good ground.
plunger to engage. This moves the arm (4) Turn the key switch to the start position.
causing engagement of the drive pinion into
the flywheel.
The test light should illuminate or the volt-
meter should indicate system voltage. If
not, there is a problem in the supply of cur-
rent to the solenoid.
5/21/2000 3 - 23
--- Page 9 ---
SM71001 - SECTION THREE ELECTRICAL
VIBRATION/DRUM SELECTION K12 relay [line 37 and 40]. At this point, K7
CIRCUITS relay remains powered even though switch
S18 has opened. The switched contacts of
The machine is designed to provide vibra-
relay K7 prevents current flow if switch S20
tion to either the front or the rear drums, or
were depressed. Relay contacts K10 [line
both drums, dependent upon the selection
31] open to prevent current flow from switch
of the three momentary push button switch-
S19 if depressed. Relay K13 [line 29] acti-
es S18, S19, or S20 on the left control pan-
vates the front exciter (shown later). Diodes
el. The selection of vibration with switch
V2 and V3 prevent the flow of current into
S11, as well as the selection of frequency
the rest of the circuit.
with switch S12 must be made for activation
of vibration. The circuit is designed so that
The momentary closure of switch S20 caus-
once a drum selection switch has been de-
es a similar function, providing power to re-
pressed, the depression of a second drum
lay K9, K11, K12 as well as K14 which
selection switch will be electrically ignored.
activates the rear exciter (shown later). Di-
It will be necessary to stop vibration before
odes V1 and V2 prevent the flow of current
another selection can be made.
into the rest of the circuit.
The circuit is powered by fuse F5 and re-
When momentary switch S19 is depressed,
quires the closing of switch S12 for circuit
relay K8 is activated as well as relay K12.
power. As shown, current cannot flow be-
Diodes V1 and V2 prevent current flow to
yond the three selector switches S18, S19,
the rest of the circuit. With the K8 contacts
or S20. One of the switches must be closed
open [line 27] the S18 and S19 circuits be-
to allow the current to flow. Momentary clo-
come diabled.
sure of switch S18 (front drum) provides
power to relay K7 [line 27 and 33] bringing
power to V4 diode, K7 relay, K10 relay and
5/21/2000 3 - 33
--- Page 13 ---
SM71001 - SECTION FOUR HYDRAULICS
STEERING SYSTEM pass through the valve and discharge out
‘T’ port, flow through the hydraulic filter and
The steering supply pump is a 9.0 gpm (34 into the charge oil circuit. Oil in the ‘L’ and
l/min) gear type pump which is mounted di- ‘R’ passages, as well as the oil in the steer-
rectly to the engine at the rear of the front ing cylinders is trapped and cannot flow,
timing cover. It supplies the necessary flow thus the machine maintains its steering di-
of oil for the steering hand pump, the cylin- rection. When a steering correction is re-
ders, and charge supply oil. A main steering quired, the control valve meters a portion of
relief valve, set at 140 bar (1990 psi), pro- the oil from the ‘P’ port to the ‘L’ or ‘R’ port,
tects the steering pump and the steering dependent on the direction the steering
control valve. Two circuit relief valves, set at wheel is rotated, and out to the cylinders.
200 bar (2844 psi), protect the cylinders The stroking of the cylinders results in the
and hoses from shock loads. All three of the turning of the machine. As oil flows into one
relief valves are located in the steering con- end of the cylinders, oil discharges from the
trol valve. opposite end and returns to the steering
control valve, discharges out ‘T’ port, flows
Oil from the reservoir passes through the through the filter and into the charge circuit.
steering supply pump and is directed to the
‘P’ port on the steering control valve. If a
steering correction is not required, oil will
5/21/2000 4 - 13
--- Page 15 ---
SM71001 - SECTION FIVE POWER TRAIN
DRUM INSTALLATION
1. Roll or lift the drum into position in the machine’s front frame. The drum must be posi-
tioned for alignment of the drive motor bracket to the left side frame bolt holes.
2. Install the bolts in the front and rear buffer brackets on the right side of the machine. This
will allow the machine frame to be lowered or raised as needed to complete alignment of
the drive motor bracket on the left side of the machine.
NOTE: To complete alignment of the left side gearbox and plate might require hooking up
the machine’s brake system and using the hand pump to release the brake on the gear-
box (see the brake section of this manual on releasing the brakes for towing).
3. Tighten and torque the motor bracket and buffer bracket bolts.
4. Install the hydraulic hoses on both the vibration and drive motors. NOTE: Fill all motor
ports with clean hydraulic oil prior to hose installation.
5. Start the machine engine and allow the hydraulic systems to develop charge pressure.
Allow the engine to run at low idle for several minutes without loading to fill and flush the
system.
6. It may be necessary to bleed the brake system at the brake ports.
5/21/2000 5-9
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SM71001 - SECTION SEVEN VIBRATION SYSTEM
5/21/2000 7-5
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DRUM - RIGHT SIDE
5/21/2000 7 - 15
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SECTION EIGHT
STEERING SYSTEM
5/21/2000 8-1
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SM71001 - SECTION EIGHT STEERING SYSTEM
5/21/2000 8 - 11