23 · Diagnostics

Clutch slipping

Make: Alfa Romeo
Model: 159 Factory Service Manual
Year: 2005–2011
Section: Clutch › Clutch slipping

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Fault diagnosisClutch slipping

CLUTCH SLIPPING

0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Carry out a driving cycle simulating a hilly/urban route with frequent gear chages to heat up the clutch/engine assemblies. Assess the problem in the following usage conditions: with the vehicle speed constant in 3rd-4th speed and the engine speed about 4-5 revs max torque, accelerate the engine rapidly with the accelerator pedal fully depressed. carry out departures from a standstill on a flat surface re-engaging the clutch and accelerating gradually from an initial engine speed of 1000-1500 rpm. Carry out a departure from stationary in 4th gear releasing the clutch pedal gradually and checking for the fault: the vehicle does not move and the engine does not cut out.	Move on to Step 1
1	CLUTCH LEVER TRAVEL CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check, inside the engine compartment, that when the clutch pedal is pressed the clutch control lever on the gearbox completes the correct travel.	Move on to Step 7	1. Clutch lever on gearbox travel incomplete.	1. Move on to Step 2
		Move on to Step 7	2. Clutch pedal free play insufficient.	2. Move on to Step 2
2	CLUTCH PEDAL CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Clutch pedal disconnected from transmission Op. 3330B26 CLUTCH PEDAL - R+R check that the travel is free and there is no sticking or hardening.	Move on to Step 3	Clutch pedal clearance or hardening.	Replace the pedal Op. 3330B26 CLUTCH PEDAL - R+R
3	OPERATING CYLINDER PUSH ROD SLIDING CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the clutch operating cylinder push rod travel and return in the rest position Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R.	Move on to Step 7	Clutch control cylinder push rod travel incomplete.	Release the clutch control cylinder from the lever and check that the latter is free Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R. If it is free, move on to Step 4, otherwise move on to Step 7
4	CLUTCH CONTROL CYLINDER CHECK (ON VEHICLE)	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Release the cylinder from the clutch control lever, keeping it connected to the hydraulic system. Press the pedal producing the thrust pressure and check the push rod travel. Using a drift, retract the push rod checking that it travels freely.	Move on to Step 7	Clutch control cylinder malfunction.	Remove the clutch control cylinder Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R. and move on to Step 5.
5	CLUTCH CONTROL CYLINDER CHECK (WITH GEARBOX REMOVED)	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	With the part at the bench, apply pressure (using compressed air) and check the push rod travel (the test mirrors what was done in the vehicle). N.B.: This test is designed to ensure that the problem is due to the cylinder and not to the pipes or the pump.	Move on to Step 6	Clutch control cylinder malfunction.	Replace the clutch control cylinder Op. 1820B38 HYDRAULIC CLUTCH ACTUATOR WITH COAXIAL CONTROL - R.R WITH GEARBOX REMOVED
6	CLUTCH PEDAL TRAVEL CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	With the system disconnected, check that the travel is correct when the pedal is pressed and released.	Move on to Step 7	1. Hydraulic pump malfunction.	1. Replace the pump Op. 1820B20 MASTER CYLINDER (PUMP) - R + R
			2. Flexible pipe from clutch reservoir to pump worn or distorted.	2. Replace the pipe Op. 1820B40 HOSE FROM CLUTCH RESERVOIR TO MASTER CYLINDER (PUMP) - R + R
			3. Flexible supply pipe to clutch control cylinder worn or distorted.	3. Replace the pipe Op. 1820B56 RIGID PIPE FROM VIBRATION DAMPER TO SLAVE CYLINDER - R R
7	PLATE LEVER AND BEARING CHECK (WITH GEARBOX REMOVED)	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	After the gearbox has been removed, check that there is no hardening of the lever (as a result of dirt or insufficient greasing) and that the plate bearing slides freely in its housing and shows no signs of damage. The thrust bearing offset reference on the diaphragm spring may indicate that the centering is not correct.	Move on to Step 8	1. The presence of dirt or wear due to insufficient greasing does not allow the thrust bearing to slide correctly.	1. Replace the faulty or damaged components.
		Move on to Step 8	2. Thrust bearing not correctly centered.	2. Ensure that the bearing is correctly centered.
8	CLUTCH ASSEMBLY CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Visually inspect the state of the clutch assembly, making sure there are no breaks and/or signs of overheating on the plate, obvious deterioration of the driven disc or grease/oil on the friction surfaces. Measurements using the gauge as in the manual.	Move on to Step 9	1. Obvious deterioration of the clutch disc and/or plate broken.	1. Replace the assembly Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
			2. Clutch plate with vitrified seal.	2. Replace the clutch plate Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
			3. Oil or grease on the disc.	3. Remove the oil or grease on the disc.
			4. Diaphgram spring broken.	4. Replace the mechanism Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
8	CLUTCH ASSEMBLY CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Visually inspect the state of the clutch assembly, making sure there are no breaks and/or signs of overheating on the plate, obvious deterioration of the driven disc or grease/oil on the friction surfaces. Measurements using the gauge as in the manual.	Move on to Step 9	1. Obvious deterioration of the clutch disc and/or plate broken.	1. Replace the assembly Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
			2. Clutch plate with vitrified seal.	2. Replace the clutch plate Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
			3. Oil or grease on the disc.	3. Replace the assembly
			4. Diaphgram spring broken.	4. Replace the assembly Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
9	CLUTCH SLIDING SPLINED HUB CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the following, in order: for excess grease on the clutch plate hub bushes and the gearbox main shaft; the condition of the main shaft hub.	Move on to Step 10	Main shaft damaged, hub worn, excess grease on the bushes.	Replace the hub and/or main shaft.
10	FLYWHEEL CONDITION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the flywheel. In particular, check: the state of the surface; wear; cuts; presence of grease/oil on the disc surfaces; signs of overheating.	End of diagnosis	1. Flywheel damaged.	1. Replace the flywheel Op. 1024B10 ENGINE FLYWHEEL - R + R FOR VERSIONS WITH MANUAL GEARBOX
		End of diagnosis	2. Presence of dust in the flywheel friction seal.	2. Remove the dust from the flywheel friction seal.

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Parts & tools for this job For 2005 Alfa Romeo 159

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