5 Brake PDF
5 Brake PDF
5 Brake PDF
General description
The machine is equipped with a fully hydraulic brake system that has two circuits: one for the front axle and one for the rear
axle.
The system consists of a foot brake valve and accumulator block with three accumulators. One accumulator is for the front
circuit, one is for the rear circuit and the third is shared.
The accumulators are pre-charged with nitrogen gas. Their purpose is to store pressure and to ensure good braking
performance by a wide margin.
The brake system is supplied with oil via the central block from Pump 3 (P3), Pump 1 (P1) or Pump 2 (P2). P3 is located on
the engine's power take-off on the machine's left side. P2 is located on the transmission's left side. P1 is located on the
transmission's right side.
P3 supplies the cooling fan and ensures brake charging during transport operation. P2 supplies the brake system passively
when using the working hydraulics and the system pressure exceeds 12 MPa. P1 supplies the brake system passively if the
steering is used and pressure exceeds 12 MPa.
As brake charging may take place from two different pumps, it is necessary to perform two different pressure checks when
checking function.
The purpose of the central block is to distribute the oil and pressure to the brakes, steering (prioritized) and servo and
working hydraulics.
If the brake pressure drops below 9.0 MPa (1300 psi), this is indicated on the display panel. The warning light and the central
warning will come on and a buzzer will sound.
The front and rear axles have wet disc brakes.
The brakes are cooled by means of each disk having a pump rotor which act as a circulation pump for the axle oil.
The axles have integrated wear indicators for checking brake disc wear.
Description of central block, refer to Section 9.
Figure 1
Brakes, principle illustration
Hydraulic pumps
Pump 2, hydraulic (passive) brake pressure charging
Pump 2 (P2) feeds the central block and thus primarily supplies the steering with oil. When the steering is saturated with oil,
the priority spool (4) shifts to brake pressure charging, servo system and working hydraulics. The pressure reducing valve (3)
uses the priority spool to limit the maximum steering system pressure to 21.5 MPa (3120 psi). If all of the oil flow to the
steering isn't used, then P2, via the priority spool, will supply the pressure reducing valve (1) providing a brake pressure of 16
MPa (2320 psi) and pressure reducing valve (2) providing a servo pressure of 3.5 MPa (510 psi). The excess capacity can be
used by the working hydraulics via connection (PW).
Figure 2
When the V-ECU receives a signal from SE504 it changes the signal controlling proportional valve MA202 from fan mode to
brake charging mode (A/B). MA202 in turn controls the work of P3. The oil is now provided at the correct pressure.
The signal controlling MA202 is of PWM type. If the requirement for cooling is great, the fan motor receives a large flow of
oil producing a high fan speed. If the pressure exceeds 12 MPa (1740 psi) the brake accumulators are charged automatically.
If the pressure in the brake accumulators drops below 9 MPa (1300 psi), SE502 provides a warning via the instruments and
display.
Foot brake valve
The foot brake valve is of proportional type, which means that the output brake pressure is proportional to the angle of the
brake pedal. The valve has two circuits: one for the front axle brakes and one for the rear axle brakes. The maximum output
brake pressure is limited to 8 MPa (1160 psi). This reduced brake pressure can be adjusted on the underside of the valve by
increasing or reducing the travel of the pedal.
Figure 3
Foot brake valve
1 Piston
2 Adjusting screw for circuit pressure
3 Security seal
4 Adjusting screw for pedal clearance
5 Pressure check connection
SE301 Sensor, brake lights
SE501 Sensor, output brake pressure,
log/transmission disengagement
Figure 4
Hydraulic diagram, cooling fan, brake system (see Section 9 for larger diagram)
NOTE!
Brake work should be conducted under clean conditions.
1. Start the engine and charge the accumulators. Raise the lift arms. Secure the boom with support 999 3831.
Stop the engine and apply the brake fully. Connect the service display unit to the machine or a pressure gauge to
the pressure check connection for output brake pressure to check that the brake is fully applied.
NOTICE
The brake must be applied during the whole wear check.
Figure 1
1. Wear indicator
Figure 3
Press in the wear indicator pin
4. Brake disc wear is indicated by the position of flat surface B on the wear indicator pin in relation to flat surface A of
the nipple.
The position of the flat pin surface varies depending on the extent of brake disc wear. For new brake discs, the
indicator pin cannot be pressed in farther once the flat pin surface protrudes 2.3 mm (0.1 in) from the flat nipple
surface.
Figure 4
Checking brake disc wear
5. The brake disc is worn and must be changed when the flat surface B of the wear indicator pin is flush with the flat
surface A of the nipple.
Figure 5
Brake disc is worn
Removing
NOTE!
The brake disc is delivered as a spare part without pump rotor. Transfer the pump rotor to the new disc and centre it. Use
the new bolts, lock nuts and spring pins that are supplied with the new disc.
1. Lift up the machine and position axle stands under the axle. Remove the wheels.
2. Drain the oil from the hub reductions and the axle housing.
AWB 30 oil volume, including hub reductions: approx. 41 l (10.8 US gal)
AWB 31 oil volume, including hub reductions: approx. 36 l (9.51 US gal)
3. Release the brake system pressure by depressing the brake pedal repeatedly (30–40 times).
4. Mark up the hub reduction's position in relation to the axle housing, connect lifting device 999 3802 to the hub
reduction. Remove the retainer bolts and remove the hub reduction.
Hub reduction weight: approx. 250 kg (551 lbs)
NOTE!
Sometimes the drive shaft and the brake disc may remain in the hub reduction and may come out complete.
Figure 1
Removing hub reduction
1. 999 3802
Figure 2
Brake plate and guide pins
1. Brake plate
2. Guide pins, 4 pcs.
6. Loosen the lock nuts. Turn out the adjusting screws for the brake piston approx. 1 turn.
Clean and check the parts for any wear and damage.
Figure 3
7. The wear indicator pin on the front axle must be fitted from the hub side when the front frame prevents removal
from the outside. The brake piston must be removed and the seal rings must be changed.
Figure 4
Centring pump rotor halves on brake disc
NOTE!
Applies only to the front axle, where the wear indicators must be fitted from the hub side when the front frame
prevents removal. For the rear axle, continue under the heading Installing.
10. Fully depress the brake pedal and block it in that position with a suitable tool. When the brake pedal is blocked in
the depressed position, the oil in the hydraulic tank is prevented from running out to respective brake piston.
NOTE!
The brake pedal must remain blocked until the front axle is refitted.
11. Remove the brake piston using a pry bar. Collect the oil that drains.
Brake piston weight: 17 kg (37.5 lbs).
Clean and check the parts for any wear and damage.
Figure 5
Removing brake piston
12. Grease the brake piston and the O—rings. Fit the O—rings with the flat surface against the bottom of the groove
on the brake piston.
Figure 6
1. O—rings
13. If the wear indicator's pin cannot be fitted after the brake piston has been installed:
Adjust the length of the wear indicator's pin so that it is 89 mm (3.5 in) (basic adjustment)
Figure 7
Basic adjustment, wear indicator
A. 89 mm (3.5 in)
Figure 8
Installing wear indicator's pin
Installing
Figure 10
Installing brake disc (principle illustration)
1. Brake disc
2. O-ring
17. Fit the brake plate and the guide pins, 4 pcs.
Figure 11
1. Brake plate
2. Guide pins, 4 pcs.
Figure 12
Installing hub reduction
1. 999 3802
WARNING
Oil under high pressure!
Figure 13
21. Start the engine and run up the brake pressure. Stop the engine and apply the foot brake.
NOTE!
The brakes should be applied until the wear indicator setting is completed and setting tool 999 3875 has been
removed.
22. Turn in the adjusting screws against the activated brake piston.
Then, turn out the adjusting screws 1/2 turn. Lock the adjusting screws with the lock nuts.
NOTE!
This procedure is only performed if a new brake disc has been installed.
24. Adjust the length of the wear indicator's pin so that it is 89 mm (3.5 in) (basic adjustment)
Figure 14
Basic adjustment of wear indicator
A. 89 mm (3.5 in)
1. 9993875
26. Remove the adjusting tool, still with the brake applied. Fit and tighten the plug on the wear indicator.
WARNING
The brake test must only be performed in a place where there is no risk of accidents.
BRAKES
Br.press.in
Br.press.out xxxxxx
yy zzz
5. If the menu for the brake test is selected, the buzzer will emit a short signal when travel speed exceeds 20 km/h
(12.4 mph), indicating that the brake test can be performed.
8. The service display unit shows the four latest measured values with the most recent value placed furthest to the left.
BRAKE TEST LOG
zz,z zz,z zz,z m/s2
xxx xxx xxx yyy
9. If the latest measured retardation value is below 4.75 m/s2 (0.48 grams), the test should be conducted again. If the
re-test value is below 4.75 m/s2, check the brake system according to
520 Brake system, checking hydraulic function and 510 Brake discs, checking wear.
Service Information
11666020 Pressure gauge 0–25 MPa (0–250 bar) (0–3625 psi), 2 pcs.
11666037 Hose, 2 pcs
9993721 Service display unit
Figure 1
NOTICE
Before checking the function of the brake system hydraulics, the maximum pressure of the cooling fan pump (pump
3) must be checked and adjusted. See Section 2 "Cooling fan pump, checking and adjusting".
NOTE!
The brake system should be free from air.
1. Release the brake system pressure in order to connect the pressure gauge by depressing the brake pedal
repeatedly (30–40 times). Connect the pressure gauge to the pressure check connection on the accumulator block.
2. Start the engine and charge the brake system. Make sure that the engine is running at low idle speed and has
reached normal working temperature.
3. Check the maximum brake pressure by tilting in towards the end position and reading the pressure on the pressure
gauge.
Max. brake pressure: 16.5 ±0.5 MPa (165 ±5 bar) (2395 ±73 psi)
Adjustment is performed on the brake pressure valve on the central valve.
NOTICE
Adjustment should be carried out with the engine turned off.
Figure 2
5. Stop the engine, leave the ignition on, and carefully brake down the pressure to 13 MPa (130 bar) (1885 psi).
Read the pressure gauge connected to the accumulator block.
Then, check the level of the pressure-drop after four "full brake applications". The pedal should be fully depressed
and completely released before the pressure drops below 9 MPa (90 bar) (1305 psi) (control light for low brake
pressure flashes on the instrument panel).
If the number of full brake applications is not completed, check the precharge pressure for all accumulators.
6. Start the engine and charge the brake system. Stop the engine.
7. Depress the brake pedal several times to release the brake pressure while checking the reading on the pressure
gauge.
The pressure in the common accumulator slowly drops to the accumulator precharge pressure, and then the
pressure continues to drop rapidly.
NOTE!
If the precharge pressure in the accumulator is below 3.5 MPa (35 bar) (507 psi), it should be changed.
Front, rear (and common) accumulator, checking
8. The front and rear accumulators can be checked on the condition that the common accumulator precharge
pressure is within the specified range.
9. Release the brake system pressure by depressing the brake pedal repeatedly (30–40 times).
Connect a pressure gauge to the brake accumulator block.
Figure 3
10. Connect the service display unit to the socket in the rear wall.
Figure 4
11. Start the engine and find the correct screen for brake pressure on the service display unit under Brake menu.
BRAKES
Br.press.in xxxxxx
Br.press.out yy zzz
12. Connect a pressure gauge to the foot brake valve to check the precharge pressure in the accumulator for the front
brake circuit.
Figure 5
1. 11666020, 11666037
13. Start the engine and allow the brake system to charge.
CAUTION
If the precharging pressure in the accumulator is below 3.5 MPa (508 psi), it should be replaced.
Service Information
Figure 1
1. 11666020, 11666037
NOTE!
The system must be free of air before the function check is performed.
Checking
1. WARNING
Oil under high pressure!
Make sure that the system has reached normal working temperature.
Start the engine and charge the brake system. Turn off the engine.
Connect the pressure gauge to the pressure check connection on the foot brake valve (front brake circuit).
2. Connect the service display unit to the socket in the rear wall.
Figure 2
3. Start the engine and locate the correct information on the service display unit under the Brakes menu.
BRAKES
Br.press.in xxxxxx
Br.press.out yy zzz
4. Depress the brake pedal so that it rests on the adjusting screw. Read off the pressure on the pressure gauge and
service display unit.
Brake circuit pressure: 8.0 ± 0.6 MPa (80 ±6 bar) (1160 ±87 psi)
Figure 3
Foot brake valve
1 Piston
2 Adjusting screw for circuit pressure
3 Security seal
4 Adjusting screw for pedal clearance
5 Pressure check connection
SE301 Sensor, brake lights
SE501 Sensor, output brake pressure,
log/transmission disengagement
Adjusting
6. Adjust the pressure with adjusting screw 2. The adjusting screw limits brake pedal movement and when adjusting,
the piston's stroke is varied.
10. Check that the clearance between brake pedal and piston is according to specifications.
Eventual adjustment is performed on adjusting screw 4.
Clearance between the brake pedal and piston: 0.4 ±0.2 mm
Plastic hose, inside diameter approx. 6 mm (0.236 in), length approx. 1 m (3 ft)
The brake system is divided into two circuits which implies that if only one circuit has been opened (a line has been
disconnected, etc.), only that circuit requires bleeding.
WARNING
Oil under high pressure!
2. Fully depress the brake pedal and hold it in position with a suitable tool.
5. Connect the plastic hose and carefully open the bleeder screw. Close the bleeder screw when oil free from air flows
out.
Figure 1
Bleeding brakes
1. Plastic hose
2. Bleeder screw
6. Turn off the engine. Adjust the oil level in the hydraulic oil tank.
7. Check function.
Service Information
Figure 1
1 Piston
2 Adjusting screw, pressure
3 Security seal
4 Adjusting screw, pedal free travel
5 Checking point
SE310 Sensor, stop lights
SE501 Sensor, output brake pressure / transmission declutch
1. Remove the foot brake pedal in order to be adjust the pedal angle.
2. Move the bolt under the pedal in order to adjust the pedal to a 35°, 40°, 45° or 50° angle. Pos. A corresponds to a
45° pedal angle.
Figure 1
Adjusting foot brake pedal angle
3. Adjust the “free pedal travel” by turning the adjusting screw (B) until the clearance between the brake pedal (1) and
the piston (2) is 0.4 ±0.2 mm (0.0157 ±0.0078 in).
Service Information
Dismantling
Figure 1
1. Remove the pedal rubber and remove the pedal together with the attaching plate as one unit (1).
3. Remove the springs and spring guide (3). Remove the valve housing from the vice.
6. Remove seal ring (A) and bushes (B) from sleeve (2).
Use a Ø 2 mm (0.08 in) pointed steel wire as a tool when removing the bushes.
Remove O-rings (D) and (E).
7. Clean and inspect with regard to damage or wear. Replace damaged or worn parts.
Assembling
10. Turn the sleeve in the vice. Install a new bush (B) and a new seal ring (A). Coat the seal ring and the bush with
grease.
Install pushrod (4).
NOTE!
If the pushrod has been dismantled, coat the threads on the bolt with locking fluid medium before assembling.
11. Install a new O-ring on plug (5). Lubricate the O-ring with clean hydraulic oil.
12. Secure the valve housing in the vice, with the hole for the sleeve facing upward. Install piston (6), the shorter spring
(7), the piston (8), the longer spring (9) and plug (5), from underneath.
Tightening torque, plug: 60 N m (44 lbf ft).
14. Lubricate with oil and install a new O-ring on the sleeve. Coat the threads on the sleeve with locking fluid medium
and install it in the valve housing.
Tightening torque: 60 N m (44 lbf ft).
15. Check that it is possible to press down the pushrod a bit by hand, and that it springs back.
17. When the foot brake valve has been installed in the machine, carry out 520 Brake system, bleeding,
520 Checking and adjusting pressure in circuit and possibly 525 Brake pedal, adjusting angle
Service Information
NOTE!
All work on the brake system must be conducted in the cleanest possible conditions. Wipe clean all pipe and hose
connections before they are disconnecting. Plug all pipes, hoses and similar equipment immediately after disconnecting.
If the functional check of the brake system indicates that one or more accumulator has insufficient precharge pressure or
lacks precharge pressure, check each accumulator as follows:
Removing
1. WARNING
An accumulated pressure remains in the brake system even if the engine has been stopped. If the system is
opened without first releasing the pressure, oil under high pressure will jet out.
Release the brake system pressure by depressing the brake pedal repeatedly (30–40 times).
2. Carefully remove the connection pipes to the accumulators and plug the connections.
NOTICE
There may be a residual pressure in the brake system.
Pressure checking
A. Accumulator
1. 11666041
2. 11666037
3. E 1234
4. 11666019
5. Included in 11666037
6. E 1281
Installing
7. Start the engine and let it run at increased rpm until the unloading (cut-out) pressure is 13.4–14.0 MPa (134–140
bar) (1943–2030 psi).
Discarded accumulators
Op nbr
WARNING
A discarded accumulator which is not punctured may still contain high pressure and must always be handled with
great care.
1. WARNING
Use safety glasses.
Figure 1
Accumulator
Figure 1
Application of the parking brake takes place with spring pressure, and this takes place every time the engine is stopped
(ignition key in position 0) or when switch SW501, to the left on the instrument panel, is activated.
When the engine is started again, the parking brake must be released by making sure that switch SW501 is in position 1
(applied parking brake) and then moved to position 0 (released parking brake).
Figure 2
Parking brake (principle illustration)
1. Plug (3 pcs.)
NOTE!
In all other cases, the parking brake is applied.
WARNING
Applied
Parking brake
Figure 3
Applied parking brake, diesel engine running and directional gear engaged gives the following:
Figure 4
Wiring diagram 15B
Service Information
Figure 1
Parking brake (principle diagram)
1. Plug (3 pcs)
Thank you for your purchase.
Have a nice day.
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