Power Train

Page 23

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Volvo Bus Service and Maintenance Manual

 Manual clutch
 Checking the clutch pedal play
41 Mechanical control: 25-30 mm.
 Hydraulic control system, push-type clutch: 4-5 mm.
 Pull-type clutch: 2-5 mm.
 Servo-powered clutch control
42 Keep the clutch pedal depressed for 2 minutes. The servo plunger must not return to its rest position. Listen for any air leakage at the servo cylinder.
43 Check the function.
 Gear-change wire (RHD buses)
 Check the function and the condition of the wire control. When replacing the wire control, carry out a basic setting according to below.

Servo-powered clutch control

Air leakage or a stiff pedal indicates that the servo cylinder needs to be adjusted.

The servo cylinder "A" distance should be between 45 and 32 mm for the clutch servo with P/N 1655639. For the clutch servo with P/N 1655435, the distance "A" should be between 40 and 32 mm. Let an assistant depress the clutch pedal and measure the distance "B". The servo plunger travel "B" must be between 28-30 mm, applies to the push-type clutch (upper fig).

Push type clutch travel check

For the pull-type clutch (lower fig), the travel should be between 30-32 mm.

Pull type clutch travel check

Function-checking the splitter

The sputter must not be engaged until the engine is fully disengaged otherwise there is risk that the splitter synchros will be damaged.

Checking the gear-changing point

This check is made with the engine at low idle, the gear lever in neutral and the parking brake on.

1.Slowly depress the clutch pedal deep enough to engage reverse without scraping and hold the pedal in that position.
2.Pre-select with the splitter toggle switch. If the splitter is already changing gear, the distance between the plate on the clutch lever and splitter cylinder should be increased (basic setting 14 mm), see page 24 (type with closing contact).
3.Then depress the clutch pedal further until the splitter gear-changes. At the correct gear-changing point, it should be possible for the clutch pedal to be depressed approx. 20-25 mm from the position in Step 1.

If the splitter does not change gear even if the clutch pedal is pushed to the floor, the play must be adjusted, see overleaf.