Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car


Mercedes S-Class
+ Mercedes-Benz cars of the class S (W-140)
- Operation manual
   Specifications
   + Access, protection
   + Elements of security systems
   + Car equipment, arrangement of devices and governing bodies
   + Comfort
   - Methods of operation and auxiliary systems
      Running in of the new car
      Parking of the car
      Start of motion and gear shifting
      Control systems of speed (темпостат) and Speedtronic
      Parktronic (PTS) system
      Amplifier of emergency brake application (BAS)
      System of anti-blocking of brakes (ABS)
      Traction control system (ASR)
      Electronic antistrange system (ESP)
      The automatic damping system of a suspension bracket
      Recommendations about driving of the car in adverse weather conditions
      Operation of the car in the conditions of winter
      Towage of the trailer
+ Routine maintenance
+ Engine
+ Cooling systems, heating
+ Power supply system and release
+ Engine electric equipment
+ Gear shifting box
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment






Towage of the trailer

The wrong placement of baggage, and also transportation of too heavy freights on the car or the towed trailer can worsen considerably controllability and brake properties of transport means / road train that it is fraught with creation of an emergency on roads!

Before a start of motion always attentively check correctness of loading of the car and trailer.


The full mass of the trailer including its own weight and mass of the freight placed in it should not exceed the extreme admissible mass of the towed trailer (see Specifications). The extreme admissible mass of the trailer depends on that, it is equipped with brake mechanisms, or not.

The maximum vertical load on the hook-on device of the car with a full mass of the trailer should not exceed 75 kgfs. For trailers with a full weight up to 500 kg it is necessary to follow the following rule:

Vertical load of a turnbuckle has to make about 10% of the full mass of the trailer. For example, if the full mass of the trailer with freight is equal to 225 kg, vertical load of the hook-on device has to make about 22.5 kgfs. Adjust load of a car turnbuckle, as appropriate placing freight on the trailer. For a start it is recommended to place freight so that about 60% of its weight were ahead of a trailer axis, and 40% - behind. If the full mass of the trailer exceeds 500 kg, try to distribute freight on trailer length more evenly (optimum load of the coupling device has to make 50 ÷ 75 kgfs). Never load the trailer so that a back part of the trailer outweighed a lobby, - it leads to unloading of back wheels of the car that worsens coupling of tires with a paving.

The full mass of the car and the towed trailer should not exceed the corresponding maximum admissible values (see Specifications).

The full mass of the car includes: the equipped mass of the car, mass of the driver, passengers and baggage, mass of the hook-on device and the mass of the trailer falling on it. Remember that the mass of the additional equipment installed on the car and the mass of the trailer falling on a turnbuckle (at towage of the trailer), reduce payload capacity of the vehicle by the corresponding sizes.


The most reliable way of check of correctness of loading of the car and trailer is weighing. Load the car and the trailer as they are usually exploited as a part of the road train, and weigh them on cargo scales.

Define values of full mass of the car and the trailer, and also masses falling on axes of the car and trailer. Compare results of measurements to requirements of Specifications.

Hook-on device

Installation of the hook-on devices which are not corresponding on the standard sizes to mass-dimensional characteristics of the trailer, or incorrectly installed on the car, can become the reason of damage of body elements of the vehicle.


The design of the hook-on device intended for installation on the car has to meet completely all necessary requirements, - consult at car repair shop of the Mercedes-Benz company.

The hook-on device has to fasten in several specially provided points on the basis of a car body that loadings from the towed trailer were distributed more evenly and fell on elements of strengthening of a body. It is forbidden to mount on the car the hook-on devices leaning only on a rear bumper which is not intended for perception of similar loadings. Installation of a turnbuckle has to be made by qualified personnel of car service.

You watch a condition of a spherical head of the hook-on device. You store a removable head together with a spare wheel in the luggage compartment of the car.

Violation of course stability of a safety lock at towage of the trailer can be minimized due to use of the stabilizer of the hook-on device, - address on company car repair shops Mercedes-Benz.

If trailer weight with freight exceeds 1500 kg, the stabilizer needs to be used without fail.

Use of the stabilizer will not damage even if trailer weight with freight makes less than 1500 kg.

Rear-view mirrors

Towage of the large-size trailer usually demands installation on the car of additional rear-view mirrors with the extended arms. Specify the requirements of the local legislation and Traffic regulations concerning towage of trailers cars. Attach the trailer to the car and estimate extent of deterioration in a rearview through standard rear-view mirrors. If the review unsatisfactory, then for reasons of safety it is necessary to equip the special mirrors providing to the driver the adequate review of space behind the car.

Connection of the trailer to the car

At acquisition of the trailer equipped with brake mechanisms track that the last had the electric drive of management, - the design of the hydraulic drive of the working brake system of the car does not provide a possibility of connection to it of any additional contours, in particular, for actuating of brake mechanisms of the trailer. Any option of connection to a brake hydraulic actuator of the car of the brake system of the trailer what attractive it would not seem will lead to deterioration in efficiency of braking of the car and decrease in traffic safety.

Connecting the trailer to the car, always use a safety chain. The ends of a safety chain have to be reliably fixed to appropriate places on the dyshl of the trailer and on the hook-on device of the car. Track that the chain passed under dyshly the trailer, - it will prevent falling of the forward end of a dyshl on the road in case of a hitch rassoyedineniye. Free length of a chain has to be sufficient not to prevent commission of turns of the road train with the minimum radiuses, however, it is not necessary to allow drawings of a chain on the ground.

Devices of external lighting and alarm systems on the trailer

Connection of the socket of an electrical wiring of the trailer to a turnbuckle leads to automatic shutdown of the Parktronic system. Activation of system happens also automatically - do not forget to remove also transitional the adapter 7/13 for connection of trailers with the 7-contact socket.


For connection of an electrical wiring of the trailer equipped with the 7-contact socket the adapter 7/13 is used special transitional (see the prevention at the beginning of subsection).

1 — the Directing ledge
2 — the Directing flute


As on trailers of various brands various laying of an electrical wiring can be used, the equipment of a turnbuckle should be charged to specialists of car service. In certain cases installation of the transitional adapter can be required.

Before connecting trailer electric equipment to the car power supply network, surely consult at car repair shop.

Preparation for towage of the trailer

Before a start of motion it is necessary to make control survey and check of the car and trailer.

Measure the vertical loading falling on the hook-on device, - use usual bathroom scales.

Check reliability of fastening of a dyshl of the trailer and a safety chain.

Check technical condition of tires and pressure of air in tires on the car and the trailer. The lowered air pressure in tires considerably worsens controllability of the car and the road train. At the same time check a state and pressure of air in a spare wheel.

Having completely loaded and having attached the trailer to the car, make sure of lack of excessive "flash" of a back part of the car, - in case of need freight in the car/trailer.

Check serviceability of functioning of devices of external lighting and the alarm system on the car and the trailer.

Specify the operating restrictions of traffic regulations for the maximum speed of the movement of the road train as a part of the car and the trailer. Planning to make a trip around several countries, in advance get acquainted with features of the local requirements and restrictions concerning towage of the trailer the car as the restrictions can work in each country.

In the European countries restriction of speed of the movement of the road train as a part of the car and the trailer is established at the level of 100 km/h.

Security measures at towage of the trailer

It is necessary to consider that the brake way of the car towing the trailer increases. Therefore, moving with the trailer, you should support the increased distance to ahead the going car. Try to avoid sharp braking and turns. It can lead to folding of the road train or even a turning of the trailer.

Remember that road train length considerably exceeds length of the single car. At turn to the right leave between edge of a carriageway and wheels of the right board of the car the bigger distance, than usually is considerable to avoid arrival by trailer wheels on a border. Consider that at turn of the road train the trailer moves on an arch of smaller radius, than the car, and can run or collide an obstacle which the car freely passed. When overtaking other vehicle you do not hurry to come back to the row as it can lead to collision of the overtaken car with the trailer.

The road train, in comparison with the single car, is more sensitive to action of rushes of a side wind and aerodynamic indignations from other cars. If you are overtaken at great speed by the heavy truck or the road train, try to support rectilinear and uniform motion of the car. To reduce the aerodynamic indignations operating on the road train from ahead the going car reduce speed to leave a turbulent stream.

At towage of the trailer load of all main units and systems of the car increases. Therefore at frequent use of the car for towage of the trailer it is necessary to carry out periodic maintenance of the car according to the regulations characteristic of intense service conditions (see the Head Routine maintenance).

Additional load of the car even more increases at operation of the road train in the hilly area. When overcoming long rises you watch closely temperature condition of the engine according to the arrow index on the control panel. At approach of an arrow of the index to an overheat zone, switch off the air conditioner (if it is equipped and included) and continue the movement. If temperature of cooling liquid of the engine does not decrease, or continues to increase, stop on a roadside and let's the engine cool down.

The conditioner of air should be switched off also at rapid increase in speed on descent at the movement in the hilly or hilly terrain. If temperature of cooling liquid of the engine constantly increases at the movement on the second transfer, reduce the speed of the movement below a mark of 60 km/h.


At the movement in the hilly or hilly terrain cyclic switching of the third and fourth transfers of automatic transmission can be observed. In this case it is necessary to pass into the lowered range of "D3" that will prevent an overheat and excessive wear of details of the AT frictional elements. In order to avoid an overheat of brake mechanisms at the movement on long descents use braking by the engine. For effective braking by the engine include the lowered range or one of the lowest steps of the automatic transmission.

At a road train stop on rise do not hold it on the place by pressing of a pedela of gas, - it can lead to AT overheat. Use the working brake system, or the parking brake.

At management of automatic transmission in the manual mode use the third, second and first transfers, being conformed with a speed of the movement of the car and road conditions. Towing the trailer, do not include the fourth transfer.

Zaparkovyvy the road train on the long parking, especially on descent or rise, take all precautionary measures for reliable braking of the car and the trailer. Turn forward wheels of the car so that when rolling the road train they rested against curbstone. Completely cock the parking brake and transfer the lever of the selector of ranges to situation "P". On the models equipped with RKPP turn on the first, or reverse gear. In addition enclose antiretractable boots under both wheels of the trailer.

The control of road train at the movement by a backing presents certain difficulties and demands from the driver of special skills and a training. Move a backing carefully and slowly, do not rotate excessively quickly steering wheel. When maneuvering by a backing in limited space it is useful that someone, standing outside, monitored movements of the trailer and directed your actions. Keep in mind that at rotation of a steering wheel clockwise (to the right) the trailer moves to the left and vice versa. When maneuvering the road train the backing recommends to hold a rim of a steering wheel from below (and not from above, as usual, at the movement by the forward course). At such successful fellow habitual compliance between the direction of turn of a steering wheel and the movement of the trailer remains: hand shift leads to turn of the trailer also to the left to the left and vice versa.