Vibrations at steering wheel, troubleshooting · ad4600d500004a · Mercedes-Benz WIS

AD46.00-D-5000-04A

Vibrations at steering wheel, troubleshooting

Model

414, 636, 638, 639, 690, 900, 901, 902, 903, 904, 905, 906, 909

General assessment of vibrations at steering wheel

Vehicles with gasoline and diesel engines differ in terms of the operating-related feel of the steering wheel due to the difference in the design. "Pulsation" is more likely to be perceived on diesel vehicles than on gasoline vehicles due to the "harder" combustion and lower idle speeds.

Slight vibrations can occur when the vehicle is idling; these vibrations are no cause for complaint. Rough running and speed variations in the engine can also have a direct effect on the steering system in the form of vibration. For this reason, it is necessary to ensure that the engine is operating properly before performing any further tests.

 Check whether the customer is perhaps complaining about a series production configuration. Take comparable vehicle if necessary.

 Check whether the vibrations can be reproduced.

 Check whether vibrations can be felt at the steering wheel when the steering is not turned or only when the steering is turned.

 Check whether the vibrations are the same when steering left and steering right.

 Check the operating temperature at which the vibrations occur.

 Check whether the engine shows any signs of irregular operation.

 Check whether the same vibration can be felt at the gearshift lever, on the vehicle floor or on the seats.

 Check whether the vibration is a pulsation (up to approx. 4 Hz) or a high-frequency vibration (tingling, tickling).

 Check at which speed the vibrations can be felt (stationary/parking, in which km/h range).

 Check whether any of the hydraulic hoses is resting against another component. When operating the steering, check whether the hydraulic hoses move when under pressure.

 Check whether road condition has any effect on vibration (rough/smooth surface).

Specific checks	Notes
Influencing variables	Switch refrigerant compressor on and off. Set to "0", not just to "AC OFF". Any effect? Check whether a correlation exists between the vibration and the selector lever positions (P/R/N or D) on vehicles with automatic transmission.
Effect of wheels	Check that the wheels have no flat spots or imbalance. If necessary, test wheels must be mounted in order to allow assessment.
Dependent on engine speed	Check whether the vibrations change with rpm. Always present or only in certain rpm ranges? If so, in which rpm range? Vibrations during vehicle operation  Assess vehicle in various gears and gear ranges, and observe correlation with engine speed.
Correlation with speed	Check whether the vibrations occur only in a certain vehicle speed range.

	Component	Notes	Remedy
1	Power steering pump	Vibrations caused by the power steering pump are usually of a relatively high frequency and are perceivable as tingling. Frequently noises can also be heard at the same frequency. Vibrations caused by the power steering pump change with the engine speed and the built-up steering pressure.
		Vibration can be felt in all engine speed ranges and is not caused by hoses making contact at the engine 	Replace power steering pump.
2	High-pressure hose	Usually, steering vibrations are caused by a hydraulic hose (primarily high-pressure hose) making contact somewhere resulting in vibration being transferred to the steering. The high-pressure hose is designed and matched to the respective engine variant such that it dampens and filters out the hydraulic vibrations occurring during operation so that they can no longer be felt at the steering wheel.
		Check whether hydraulic hose makes contact with body or engine
		Note: - Hydraulic hoses move when under pressure. - Check hydraulic hoses when under pressure.
		Hydraulic hose makes contact 	Align hydraulic hose.
		Note: If a new hose variant is available, it will be replaced by Parts and, if necessary, published in a GI (TIPS). If vibration complaints occur and new hose variants are available, they can be used. Especially if the complaint is restricted to a particular engine speed range and the causes are not engine-related. If no remedies are known: Call the MPC hotline.
3	Engine mount/engine operation	If the engine does not run smoothly or if the engine mountings are inadequate, this can have a direct effect on the steering. Check whether the engine is running irregularly:
		Engine is running irregularly 	Eliminate rough operation.
		Engine is running smoothly 	- Check engine mounts for correct seating and release tension. - Relieve stress on exhaust system.