Great Wall Hover. Manual - part 77

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The action of load-sensing proportional valve is to prevent the rear wheel is braked before the front wheel is braked by adjusting the

distribution of front and rear brake force according to the difference of vehicle rear shaft load, then avoid the risk of vehicle rotation.

The adjustment of proportional valve is shown as follows:

a. The rear shaft load can be 820Kg after adjustment (including driver).

b. Install the brake pressure measuring meter and drain the air.

c. Increase the front brake pressure to 12Mpa, the rear brake pressure should be within 8

9 Mpa.

d. If necessary, adjust the hydraulic pressure.

1. Move the sensing spring bracket on the rear axle, the right hook of sensing spring moves to right; the rear brake

pressure is  increased .

2. Vice versa, the rear brake pressure decreases, the adjustment scope of the frame is 20mm.

3.  The extension amount of spring of load sensing proportional valve is controlled within 84

95mm.

Adjustment load-sensing proportional valve

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Replace of load-sensing proportional valve

1. Removal

Disconnect the brake pipeline form the valve; remove the lock nut and

remove the adjusting bolt from the suspension arm bracket; remove the

installation bolt and take off the  load-sensing proportional valve assembly.

2. Installation

a. Use two installation bolts to fix the load-sensing proportional valve.

The bolt tightening torque is 23N

m,

b.   Tighten the adjusting bolt locking nut,

c. Connect each brake pipeline.

The tightening torque of the connector is 16N

m,

d. Filled with the brake fluid, discharge the air from the brake system;

check the brake pressure and leakage.

output manometer

input manometer

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Antilock Braking System (ABS)

Cautions

1.

It must not remove or install the electric elements and wire bunch plug when the ignition switch is in ON to avoid

the damage of ECU. It should turn off the ignition switch if needs disassembly.

2.

Pay attention to do not knock or impact the ABS ECU during the maintenance and repair, for it will damage the

ABS ECU easily.

3.

The wheel speed sensor and hydraulic unit (integrated with ECU) of BOSCH ABS8.0 can not be repaired, it should

be replaced in integral if damaged.

4.

After the brake system is maintained, the brake pedal maybe soft. Discharge the air according to the normal brake

system.

5.

It must use the brake fluid from original manufacturer; the brake fluid of different number cannot be used in mixed,

otherwise it will cause the failure of brake system. Select the tyre of original type as most as possible

Repair of Antilock Braking System (ABS)

1.

It should process the failure diagnosis for the brake system before process the ABS failure diagnosis. It can

diagnose out the failure rapidly by using Table 1. In Table 1, the small number means the failure which occurs most

possibly. Check each element according to the sequence and maintain or replace it if necessary.

2.

Check the following elements for normal operation before the diagnosis:

 Brake fluid level and brake fluid quality

       Pressure of tyre, size of tyre, shape and depth of tyre figure

       Other brake component

These components will affect the brake effect of the ABS. Check the system sensor, connecting wire and connector for correct

installation, arrangement and connection. Ensure the completeness of fuse, repair or replace it if necessary.

3.

Process the analysis and diagnosis according to the ABS advanced by owner. Use the diagnosis instrument (Annex

1) for final check and confirmation. It must process the run inspection after the competition of all  ABS maintenance.

The test condition is shown as follows:

a.

Confirm the tyre complies with the requirement, the tyre pressure is normal.

b.

The brake system (including brake light ) is normal

c.

The brake system is without leakage.

d.

The position and installation of wheel speed sensor is correct.

e.

All fuses are normal.

4.

test method:

Run for 1 min at least when the vehicle speed is beyond 40Km/h, process a proper brake. Then read out the failure code to

ensure the ABS is without failure code.

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