Removal and installation of the main brake cylinder. 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
9. Manual box of gear shifting (RKPP) and automatic transmission (AT)
10. Transmission line
11. Steering and suspension bracket
12. Brake system
12.1. General information
12.2. General information on anti-blocking brake system
12.3. Replacement of blocks of disk brake mechanisms
12.4. Removal, major maintenance and installation of a support of the disk brake mechanism
12.5. Survey, removal and installation of a brake disk
12.6. Replacement of boots of drums of brake mechanisms
12.7. Removal and installation of the main brake cylinder
12.8. Condition check, removal and installation of the vacuum amplifier of brakes
12.9. Description, removal and installation of the vacuum hydraulic booster of brake system
12.10. Replacement of a cable (cables) of a drive of the parking brake
12.11. Adjustment of the parking brake
12.12. Condition check, removal and installation of assembly of the parking brake
12.13. Adjustment of a pedal of a brake
12.14. Check and adjustment of the switch of a stoplight
12.15. Survey and replacement of brake lines and hoses of hydraulic system of brakes
12.16. Pumping of hydraulic system of brakes
12.17. Diagnostics of malfunctions of 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
 













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12.7. Removal and installation of the main brake cylinder

Brake liquid is poisonous. It also strongly dissolves paint. See. The prevention in the Section Pumping of hydraulic system of brakes.


Though for the majority of models there are spare parts and a set for repair of the main cylinder, all of us recommend its complete replacement on new or capitally repaired. It is required to you much more time for repair of the main cylinder, than for its replacement, besides you cannot define, whether your main cylinder is subject to major maintenance until will remove it. And after that it can appear that it cannot be repaired.

Removal

 PERFORMANCE ORDER

  1. The main cylinder is connected to the vacuum amplifier of brake system, and both of them fasten on a partition in the left part of an impellent compartment. To remove the main cylinder, disconnect the electric socket (the top arrow), the union of the hydraulic brake line (the bottom right arrow, other union is not visible on this photo) and give two nuts of fastening of the main cylinder (the bottom left arrow, other nut is not visible on this photo).
  1. By means of a syringe pump out as much as possible liquid from the tank.
  2. Place pieces of rags under shtutserny connections of the line and prepare covers or plastic packages to stop up the ends of tubes after their detachment.

Brake liquid damages paint. Cover all parts of a body and try not to spill liquid during this procedure.

  1. Release connecting nuts on the ends of brake tubes where they incorporate to the main cylinder. To prevent breaking лысок on these nuts, it is necessary to use a special cutting cap ("brake") wrench which covers all nut.
  2. Accurately pull out brake tubes from the main cylinder and stop up their ends to prevent hit of dirt and leakage of liquid.
  1. Disconnect all electric sockets from the main cylinder, then give nuts of fastening of the main cylinder to the vacuum amplifier of brakes. Pull together the cylinder from hairpins and pull out it from an impellent compartment. Also be again careful not to spill liquid. Will throw out a sealing ring between the main cylinder and the vacuum amplifier.

Always it is necessary to replace this sealing ring. The defective ring can serve as a vacuum cause of infringement that will reduce overall performance of brake mechanisms and will lead to their periodic failure.

Pumping procedure

 PERFORMANCE ORDER

  1. Before installation of the new or capitally repaired main cylinder it should be blown on a workbench. It is recommended to establish the main cylinder in a vice since it is necessary to submit pressure upon its piston, and at the same time to operate a stream from exhaust outlets of brake tubes. Use a vice with the protected sponges and do not tighten them too strongly, differently the case of the main cylinder can burst.
  2. Insert caps with a carving into exhaust outlets of the brake line. Tighten them so that them air but that they needed to be released did not get.
  3. Fill the tank with brake liquid of the recommended type (see. Head Routine maintenance of the car).
  4. Pull out one cap and push piston assembly in a mirror of the main cylinder to remove from the cylinder air. Use for this purpose a big crosswise screw-driver.
  5. To prevent air hit back in the main cylinder, it is necessary to establish and tighten a cap before release of pressure on piston assembly.
  6. Repeat procedure until from an exhaust outlet of the brake line brake liquid without air vials will not go. Repeat procedure for other exhaust outlet of the brake line with a cap. Watch level of brake liquid in the tank to prevent air hit in system.
  7. In pumping procedure on a workbench the high pressure therefore the caps described above, it is not obligatory to establish each time at a piston otpuskaniye is not used. Instead, before releasing the piston, densely close an opening a finger that air did not get back to the cylinder. Wait some seconds that brake liquid got from the tank to the piston cylinder, then again squeeze out the piston, having cleaned a finger at a liquid effluence. Do not forget to close an opening a finger each time before a piston otpuskaniye, and when procedure for this opening will be finished, establish a cap and tighten it before passing to other opening.

Installation

 PERFORMANCE ORDER

  1. Establish the main cylinder (together with a new sealing ring) on hairpins of the vacuum amplifier and tighten fastening nuts while fingers.
  2. Attach unions of the brake line to the main cylinder. As the main cylinder is not absolutely well fixed yet, it can be moved slightly that it was easier to attach unions. Do not strip a thread at a tightening of shtutserny connections.
  3. Tighten shtutserny connections of brake system and fixing nuts with demanded effort.
  4. Fill the tank of the main cylinder with brake liquid, then pump over the main cylinder (only if it was not pumped over any more) and brake system as it is described in the Section Pumping of hydraulic system of brakes.
  5. To pump over the cylinder directly on the car ask the assistant to squeeze out several times a pedal of a brake and then to hold it completely squeezed out. Release a nut of shtutserny connection to give to air and liquid to leave, then tighten a nut. Repeat this procedure until liquid without air vials will start to leave. Carefully check work of brakes before the beginning of normal operation of the car.


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12.6. Replacement of boots of drums of brake mechanisms
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12.8. Condition check, removal and installation of the vacuum amplifier of brakes