Mercedes-Benz M-class W163 - Repair manual and operation

3.5. Check of a condition of tires and pressure in them, designation of tires and disks of wheels, rotation of wheels

PERFORMANCE ORDER

Depending on model and equipment tires and disks of various sizes can be installed. Disks have depth of a press fitting of 38 mm, - depth of a press fitting is called the distance from the middle of a disk to a persistent surface of a wheel on a brake disk or a drum. Wheel bolts for steel and light-alloy wheels have the identical sizes. At installation of light-alloy wheels of other producers bolts of other sizes can be required. The equipment is improved. Can be so that for older models other values of pressure in tires are admissible. The sizes specified in documents to the car are defining. At a sports manner of driving it is recommended to increase pressure in forward and back tires by 0.2 kgfs/cm2. At increase in pressure it is necessary to proceed from a base-line value for various conditions of loading. Winter tires as a rule have pressure 0.2 kgfs/cm2 higher than summer. It is necessary to consider recommendations of manufacturers of winter tires. As winter tires have restriction on speed, in sight of the driver the plate with the indication of the maximum speed has to be strengthened.

Designations of disks

Example 6Jx15

6 — Width of a disk in inches

J — Alphabetic reference of height and a contour of an onboard zakraina of a rim of a disk

x \Designation of an integral deep disk

15 — Diameter of a disk in inches

Admissible side beating on the onboard zakrayena of a disk: 0.8 mm;

Admissible radial beating on the landing shelf of a disk: 0.5 mm.

Designation of tires

Example: 195/70 R 14 89 H

195 — Width of the tire in mm

/70 — Height relation to width (height of cross section of the tire makes 70% of width)

If separate data on width relation to height are absent (for example, 175 R 14), means it is about the "normal" relation. It makes 82%.

N — the Class of speed, N: to 210 km/h (on new tires it is brought not always).

R — the Radial design

14 — the disk Size in inches

89 — loading capacity Parameter

If between data 14 and 89 there is a designation M+S, it is about tires with a winter protector.

N — Designation of admissible maximum speed.

Symbols of speed belong both to summer, and to winter tires. Alphabetic references of speed are given in Specifications.

Date of production of the tire

Production is dated the tire in a code of the producer

Example: DOT CUL2 of UM8 019 TUBELESS

DOT — Department of Transportation (U.S. Department of Transportation)

CU — reduction of the name of the manufacturer

L2 — the tire size

UM8 — execution of the tire

4600 — date of production - the 46th working week 2000

TUBELESS — tubeless (TUBETYPE - the tire with the camera)

• Regular check of a condition of tires will allow you to avoid the troubles connected with stops in way because of the lowered wheel. Besides, such checks give valuable information on possible problems with steering and a suspension bracket before emergence in them serious damages.
• Tires are equipped with the built-in strips of indication of wear of a protector which are bared at decrease in depth of a protector to 1.6 mm then tires are considered as worn-out. This size represents minimum admissible depth of a protector; it is in most cases recommended to replace tires which depth of a protector makes 2 mm and less. Depth of a protector can also be determined by the simple and inexpensive adaptation known under the name of the measuring instrument of depth of a protector.

Indicators of wear of a protector of the tire up to the depth of 1.6 mm are in the places designated on TWI sidewall

• Pay attention to any unusual wear of protectors. Such defects of a protector as cavities, cambers, flattening and stronger wear on the one hand indicate violation of angles of installation of forward wheels and/or balancing of a wheel. At identification any of the listed defects it is necessary to address for their adjustment in a tire workshop.
• Carefully check the tire for existence of cuts, punctures and the got stuck nails or buttons. Sometimes after piercing of the tire a nail it still some time holds pressure or lowers very slowly. At suspicion at first check tightness of the nipple of the gate of a rating for existence of such "slow puncture". Then examine a protector on presence at it of the got stuck foreign objects or punctures which are closed up earlier which started over again passing air. If there is a suspicion that there is a puncture, it is possible to make sure of its existence, having moistened the suspected site with soap water. In the presence of leak solution will begin to bubble. If a puncture not too big, the tire it is usually possible to repair in any tire workshop.
• Carefully examine the internal side surfaces of tires on existence of signs of leak of brake fluid on them. If those are available, immediately check the brake system.
• Maintenance in tires of the correct pressure increases the term of their service, helps to save fuel and improves the general comfort of the movement. The special manometer is necessary for check of pressure.

Always you keep the exact manometer in the ware box, - indications of the manometers which are built in nozzles of air hoses at gas stations should not be trusted.

• Always check pressure on cold tires (i.e. to a trip on the car). If to check pressure on the warm or warmed tires, it will lead to overestimate of indications of the manometer because of thermal expansion of tires. In this case it is never necessary to lower pressure since after cooling of the tire it will appear below norm.
• Screw together a protective cap from the gate of a rating acting from a disk of a wheel or from a nave cap then densely press a manometer nozzle to the gate. Consider instrument readings and compare them with recommended in Specifications. Do not forget to install into place a protective cap for prevention of hit in the mechanism of the nipple of dirt and moisture. Check pressure in all four tires and if necessary pump up them to the recommended value of pressure.
• Do not forget to support the required pressure and in a spare wheel.

Check of pressure of air in tires

PERFORMANCE ORDER

An inspection of pressure of air should be carried out only on cold tires. The values of pressure of air in tires given for small loading of the car are the minimum values providing comfort of the movement. The elevated pressure of air in tires provided at the raised car loading positively affects controllability of the car as well at small loading and is quite admissible. Smoothness of swing at the same time, however, decreases a little. Turn off a gate cap. Air pressure in tires is checked once a month, and also when carrying out service (including spare a wheel). When checking use the special manometer, or the manometer which is built in the compressor. It is not necessary to trust indications of the manometers which are built in nozzles of the compressors used for pumping of tires at petrol filling stations. Check of pressure of a rating of tires Besides, pressure of air need to be checked before each long trip since in this case temperature load of tires increases. Necessary pressure of air in tires is given in the sticker which is on inside of a cover of the fuel tank. At use of winter tires pressure of air has to be increased by 0.2 kgfs/cm2 in relation to the established value. Pressure of air of narrow tires of a spare wheel is specified on a disk sidewall. Air pressure in tires changes depending on change of temperature of air on 10 °C approximately on 0.1 kgfs/cm2. It should be considered at monitoring procedure of pressure of air in tires indoors, especially in cold season. Example: Temperature in a garage — About + 20 °C Temperature of external air — About 0th °C The established air pressure in tires = the Ordered value, + 0.2 kgfs/cm2

Check of a condition of gates of a rating of wheels

PERFORMANCE ORDER

The used extenders of gates have to be checked for existence of the damages and pollution leading to leakage. If necessary extenders should be replaced. Turn off a protective cap and the extender. Apply a small amount of soap solution or saliva on the gate. If the air bubble is formed, tighten an insert (3), - use a ledge of a metal protective cap (2). Wheel rating gate 1, 2 — Rubber/plastic and metal protective caps 3 — the Nipple 4 — the gate Case Again check the gate. If there are bubbles and the gate does not manage to be tightened, it should be replaced (work HUNDRED). Surely again establish into place a protective cap.

Examples of characteristic wear of protectors of tires

Side wear

Insufficient pressure in the tire leads to its overheat at the movement owing to an excessive deflection therefore the protector does not nestle sufficiently on the surface of the road. It leads to loss of coupling with the road and to excessive wear of a protector, not to mention danger of an exit of the tire out of operation as a result of an overheat.

Check and adjust pressure.

Wrong disorder of wheels (wear on the one hand)

Repair or replace suspension bracket details.

Too sharp turns

Reduce speed!

Central wear

Excessive pressure

Excessive pressure in the tire results in the accelerated wear of the central part of a protector, decrease in coupling with the road, more rigid movement and increase of danger of fatal damage of a slope.

Check and adjust pressure.

If you had to pump up tires for transportation of heavy freights to the value of pressure specified for this purpose in Specifications, do not forget to pit after that it upon transition to the normal mode of operation.

Uneven wear

Tires of forward wheels can unevenly wear out as a result of violation of adjustment of angles of installation of wheels. It is possible to check and adjust the angles of installation for a moderate payment in the majority of tire workshops.

Wrong disorder or выбег

Repair or replace suspension bracket details.

Defect of a suspension bracket

Repair or replace suspension bracket details.

Wheels are debalanced

Make balancing of wheels.

Convergence of forward wheels is incorrectly established

Adjust the angles of installation of forward wheels.

The Obtrepannost of edges of a pattern of a protector which is a wear sign best of all comes to light to the touch.

Rotation of wheels

PERFORMANCE ORDER

Rotation of wheels is allowed only at the identical amount of forward and back wheel assemblies. Rotation of wheels you produce each 5-10 thousand kilometers of a run depending on degree of wear of tires. At the same time you monitor preservation of the direction of rotation of wheels (for the directed tires). Rotation needs to be made until emergence of characteristic signs of wear of tires: wear of a humeral zone (forward wheels) / middle part of a protector (back wheels). At each rotation carefully clear wheel assemblies from the inside. Having finished the procedure do not forget to check pressure of a rating of tires (see above). In order to avoid weakening of fastening of wheels tighten wheel bolts strictly according to requirements of Specifications, use only company wheel bolts with a logo of the Mercedes-Benz company!

Spare wheel of the facilitated design

PERFORMANCE ORDER

At damage of the tire to the place of the failed wheel assembly the spare wheel of the facilitated design which at the first opportunity should be replaced with a wheel of a standard design is established, - the spare wheel is calculated on a run no more than 20 000 km. In case of need the tire of a spare wheel can be mounted on the driving wheel, on condition of its compliance on a standard size of other driving wheels. The tires which were in the use more than 6 years are recommended to be used only in extreme cases when there is no other exit.

Models with a complete set of AMG

PERFORMANCE ORDER

There is a danger of accident! If the spare wheel of the facilitated design is mounted, then owing to various sizes of tires it is necessary to reckon with change of dynamic properties of the car. Conform style of driving to this situation. The spare wheel of the facilitated design is provided only for short-term use at observance of the ordered air pressure in tires and the maximum speed of 80 km/h. Operation with more, than one spare wheel of the facilitated design is inadmissible.

Replacement of wheels

See Poddomkrachivaniye's Section and towage.

Bolts of fastening of wheels

PERFORMANCE ORDER

The wheel bolts damaged mechanically or as a result of corrosion development are subject to replacement. Before a vvorachivaniye wheel bolts should not be greased with any structures. In case of damage of a carving to a nave of a wheel it is necessary to drive away immediately the car on HUNDRED Mercedes-Benzs for performance of necessary recovery repair. Before installation of wheels check purity of surfaces of interface of disks to naves. In order to avoid weakening of fastening of wheels tighten wheel bolts strictly according to requirements of Specifications, use only company wheel bolts with a logo of the Mercedes-Benz company!