6.9. Signaling device

Description of the device

Fig. 6.13. Signaling device: 1 – case; 2 – short piston; 3 – ball; 4 – long piston; 5 – stopper cap; 6 – sealing ring; 7 – switch of a control lamp; 8 – trailer union; 9 – sealing washer; 10 – stopper


For the warning of the driver of damage of one of contours of system of brakes in hydraulic system of the drive the signaling device serves. It consists of the case 1 (fig. 6.13) with two pistons 2 and 4 dividing the case into two isolated cameras.
Damage of one of contours of system leads to pressure drop in one of cameras that breaks an equilibrium condition of pistons which, moving, close contacts of the electric switch 7 including a control lamp in combinations of devices.

Check of operation of the signaling device
1. Remove the signaling device from the car.

Fig. 6.14. Device for control of pressure: 1 – washer; 2 – case; 3 – copper washer; 4 – the bolt is connecting; 5 – valve of production of air; 6 – manometer


2. Attach the hydraulic actuator equipped with the manometer to one of cameras, and muffle other openings of this camera traffic jams. The design of adaptation is presented in fig. 6.14. Other camera has to be reported with the atmosphere.
3. Consistently connect a control lamp, the rechargeable battery and the switch of the signaling device.
4. Gradually increasing pressure, record pressure with which the lamp lights up.
5. Repeat the described operations with the second camera (the first camera has to be reported with the atmosphere).

       NOTE
At examinations use only fresh brake fluid recommended in the appendix 3. The same liquid it is necessary to wash out the bringing pipeline.

6. If the alarm lamp lights up with a pressure of 1,0-2,1 MPas (10,5–21,0 kgfs/cm2) and brake fluid does not leak from under the switch, so the signaling device regularly.
7. The reason of the lowered pressure putting the signaling device in action – an insufficient tightness of cuffs because of wear of a mirror of the cylinder or use of a cuff of poor quality.
8. Malfunction of the switch, the tease on a cylinder mirror, swelling of cuffs or bad washing of a mirror of the cylinder can be the reasons of the complicated switching. In this case repair the signaling device and again repeat check.
Removal and installation of the signaling device
1. Disconnect a wire from the - plug of the rechargeable battery.
2. Disconnect wires from the switch of a control lamp installed in the signaling device.
3. Disconnect pipelines from the signaling device.
4. Turn out a bolt of fastening and remove the signaling device from the car.
5. Install the signaling device upside-down. After that pump over all hydraulic system.

Repair of the signaling device
1. Remove the signaling device from the car.
2. Turn out the switch 7 (see fig. 6.13) a control lamp.
3. Take out a ball 3 of an opening under the switch.
4. Turn out the trailer union 8 and remove the sealing washer 9 established under it.
5. Turn out a stopper 10 and remove the sealing washer 9 established under it.
6. Carefully, not to damage a cylinder mirror, push out from the case pistons 2 and 4 by means of a wooden mandrel.
7. Remove from pistons sealing rings 6. Sealing rings are subject to obligatory replacement irrespective of their state.
8. Wash out details and dry up them a stream of compressed air.
9. At wear, damage or strong corrosion of surfaces of pistons and mirrors of the cylinder replace defective parts.
10. Accurately install new sealing rings on pistons.
11. Grease a mirror of the cylinder and pistons with sealing rings a thin layer of fresh brake fluid.
12. Install each piston from the relevant party. At the same time the sealing ring should not pass through an opening under a ball. Otherwise the condensing surface of a ring will be damaged.
13. Screw the trailer union and a stopper with sealing washers.
14. Grease a ball with DT-1 (TU-38-USSR-2-01-116-76) lubricant and establish it in an opening under the switch.
15. Screw the switch of a control lamp.