Description and coupling check. BMW the 5th E28/E34 series (from 1981 to 1993 of release)
Repair of BMW E28 and series E34 from 1981 to 1993
1. Cars of the BMW brand of 5-series
2. Engine
3. Cooling system
4. Power supply system
5. Ignition system
6. Control systems of the engine and decrease in toxicity of the fulfilled gases
7. System of production of the fulfilled gases
8. Coupling
8.1. General information
8.2. Description and coupling check
8.3. Removal and installation of the main cylinder of coupling
8.4. Adjustment of a pedal of coupling
8.5. Check of work and replacement of the switch of coupling (where it is provided)
8.6. Removal and installation of the executive cylinder of coupling
8.7. Pumping of hydraulic system of coupling
8.8. Removal, survey and installation of components of coupling
8.9. Diagnostics of malfunctions of coupling
9. Manual box of gear shifting (RKPP) and automatic transmission (AT)
10. Transmission line
11. Steering and suspension bracket
12. Brake system
13. Body
14. Control body sizes
15. Heater and air conditioner
16. System of onboard electric equipment
17. Routine maintenance of the car
18. Size table and adjusting data
19. Schematic electric circuits
20. Governing bodies and operation receptions
21. System of onboard diagnostics - a principle of functioning and codes of malfunctions


8.2. Description and coupling check


Models with RT are equipped with one-disk coupling of dry type with a diafragmenny spring.

Components of standard assembly of coupling

1 — Press a disk
2 — a coupling Disk
3 — the inclusion Lever
4 — Vyzhimna the bearing
5 — the Finger with a spherical tip
6 — the Fixing spring of the lever
7 — the Bolt

Coupling is put in action by means of hydraulics system.

When squeezing a pedal of coupling hydraulic liquid (under the pressure created by the main cylinder of coupling) transfers capacity to the executive cylinder. As the executive cylinder is connected to a fork of switching off of coupling, this fork brings vyzhimny the bearing into contact with petals of a press disk, deducing from gearing a coupling disk.

The hydraulic system regulates coupling automatically therefore any additional adjustment of a drive or pedal it is not required if only you did not replace the main cylinder of coupling and/or a pusher.

In the course of work with instructions there can sometimes be problems with the terminology relating to components of coupling since different producers, sellers in shops of auto parts and sellers of cars call the same details differently. For example, a conducted disk call also a coupling disk, and a frictional disk; the executive cylinder sometimes call the working cylinder, etc.


With obvious damages it is necessary to replace components, but for cases when the cause of failure of system is not so obvious, some preliminary diagnostic checks below are given.


  1. First of all it is necessary to check liquid level in the main cylinder of coupling. If it low, make having added and once again check coupling work. If you drained the main cylinder or served hydraulic system any of components, pump over system (see. Section Pumping of hydraulic system of coupling). If it is necessary to make too often having added, it for certain occurs because of leakage of liquid.
  2. For check of time of switching off of coupling start the engine and leave it to work at normal single turns at the transmission established on neutral transfer (the pedal of coupling is lifted). Switch off coupling (a pedal down), wait some seconds, then include a reverse gear. It should not be thus audible a gnash. The gnash indicates refusal of one of components, possibly, in assembly of a press disk or a conducted disk.
  3. For check of completeness of switching off of coupling start the engine (include a brake that the car did not move a little) and hold a coupling pedal approximately in 1-2 cm over a floor. Several times switch a box from the provision of the first transfer to a reverse and back. If switching is not smooth, means, any of components is faulty.
  4. Examine the plug of a pedal of coupling in the top part of a pedal to make sure that it is not worn-out and does not disturb a pedal course.

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8.1. General information
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8.3. Removal and installation of the main cylinder of coupling