10.4. Main brake cylinder

Get a set for repair of the main brake cylinder. In it there are all details necessary for repair. Rubber details on replacement, first of all consolidations are especially necessary. It is also very important to establish laying reliably and in the required direction. Be attentive at repair: lubricant or solvents with a mineral basis should not contact to rubber details.

Fig. 10.11. Main brake cylinder: 1 – sensor of level of brake fluid; 2 – tank cover;
3 – a tank for brake fluid; 4 – plug; 5 – nut; 6 – ring consolidation; 7 – lock screw; 8 – persistent ring; 9 – assembly of primary piston; 10 – assembly of the secondary piston; 11 – assembly of the main brake cylinder; 12 – main brake cylinder; 13 – brake tubes


Disconnect brake tubes from the main brake cylinder. For collecting the proceeding liquid put rags or newspapers under the main brake cylinder. Disconnect the socket from the sensor of level of brake fluid, turn off two nuts of fastening of the main brake cylinder and remove the main brake cylinder from the car (fig. 10.11).
Merge the remaining brake fluid from a tank. Remove a tank, strongly holding the main brake cylinder and shaking a tank here and there.
Install the main brake cylinder in vertical position (a forward part has to be directed down), press primary piston and remove a persistent ring.
Remove primary piston. The detail for replacement is provided in a repair kit.
Wooden core press the secondary piston, remove ring consolidation and turn out the screw.
Knock with the main brake cylinder about a wooden bar for extraction of the secondary piston.
Take out a spring from a forward part of the secondary piston.
Remove from the secondary piston a back strut and consolidation of a cup of the cylinder, laying of the valve and two consolidations from the back party of the piston.
Remove tank plugs, a cover and a float.
Clear the main brake cylinder and examine an opening on existence of traces of corrosion and damages. If considerable traces of corrosion or damage are found, replace the case of the main brake cylinder.
Examine a tank on existence of cracks, and plugs on wear, if necessary replacing them new.
Before assembly grease all elements with pure brake fluid.

Fig. 10.12. An arrangement of consolidations on the secondary piston of the main brake cylinder


Establish laying of the valve ahead of the secondary piston. Place on the piston consolidation (an open part forward) (fig. 10.12).
Install on the secondary piston the central consolidation by an open part forward.
Establish back consolidation of the secondary piston by the open party to a back part.
Install ring consolidation on the screw of fastening of the secondary piston.

Repair
Get a set for repair of the working brake cylinder.
Turn out the union of removal of air and shake out a steel ball. If necessary for extraction of a ball knock with the working brake cylinder about a wooden bar.

PREVENTION
Exclude hit of brake fluid on a paint and varnish covering of the car as it can destroy it.

Remove dustproof covers and pistons from a cylinder opening, then separate covers from pistons.
Press the piston on the one hand openings for its extraction, and also for extraction of a cup of a spring and a spring.
Clear the working brake cylinder brake fluid, the denatured alcohol or by means of installation for cleaning of the brake system. Under no circumstances do not use solvents on an oil basis for cleaning of details of brakes.
Use compressed air for removal of excess of liquid from the working brake cylinder and blow channels.
Check an opening of the brake cylinder for existence of traces of corrosion and zadir. For their removal processing of an opening is allowed by fine-grained abrasive paper, but it is necessary to replace the cylinder on new if it is impossible to eliminate defects or the opening has teases.
Grease new cups and an opening of the brake cylinder with pure brake fluid.
Install a spring, cups of a spring and a cup of the piston in the cylinder.
Make sure that cups are correctly installed (the open ends of a cup have to be directed inside).
Install new covers on pistons. Grease pistons with pure brake fluid. If the set for repair includes a set of lubricant for brakes, apply lubricant in covers (or according to the instruction).
Install pistons and covers in the brake cylinder, be convinced that covers are placed correctly.
Establish a steel ball and screw the union of removal of air.

Installation
Correctly arrange the working brake cylinder, a hand put a cap nut of fastening of a brake tube and check that there were no distortions.
Screw bolts of fastening of the brake cylinder and reliably tighten them.
Tighten a cap nut of fastening of a brake tube and establish assembly of brake shoes.
Install the brake drum and adjust hug bearings. Establish a wheel and fix it by nuts.
Remove air from the hydraulic drive of the brake system and lower the car.
Grease primary and secondary pistons with pure brake fluid.
Wooden whetstone push the secondary piston in an opening of the main brake cylinder. Squeeze a spring a little and screw the screw.
Insert primary piston a spring forward. Squeeze a spring a little, then establish a persistent ring.
Grease tank plugs, install a tank on a firm surface and, shaking it, a napressuyta the case of the main brake cylinder on a tank.
Install the float-operated sensor of level of brake fluid.

Fig. 10.13. A gap between primary piston and a pusher of the vacuum amplifier of brakes


It is theoretically necessary to measure a gap between primary piston and a pusher of the vacuum amplifier of brakes (fig. 10.13). The manufacturer for this purpose releases the special tool 49 B002 765. At its absence for determination of depth of dredging in primary piston and a vystupaniye of a pusher of the vacuum amplifier use a depth gage or the similar tool. The recommended size without the annex of vacuum to the amplifier makes 4,06–6,09 mm.
Adjustment is carried out by rotation of a pusher of the vacuum amplifier withheld by a lock-nut.
Every time at removal of the main brake cylinder it is necessary to carry out full pumping of hydraulic system. Time for pumping of system can be reduced if the main cylinder is filled with liquid and is beefy or "in a test way it is pumped over" before its installation on the car. Fill a tank with brake fluid and slowly push the piston on all length, using a wooden core or the crosswise screw-driver. Before release of the piston block connections of the highway of the brake system to prevent hit of air in the main brake cylinder, then release the piston. Repeat the procedure until from connections of the highway of the brake system brake fluid without vials of air does not begin to be emitted. Be attentive – do not assume that during pumping the tank bottom was bared.
Correctly arrange the main brake cylinder on hairpins of the vacuum amplifier of brakes and fingers, without distortions tighten cap nuts of fastening of brake tubes.
Reliably tighten nuts of fastening of the main brake cylinder.
Reliably tighten cap nuts of fastening of brake tubes and connect the socket to datcha