1. The reason for the decrease in braking efficiency may be the poor operation of the vacuum booster. To quickly check it, press the brake pedal several times with the engine off to remove the vacuum in the booster, and then, holding the pedal, start the engine. If the pedal drops slightly after starting the engine, the vacuum booster is working properly.
2. If the pedal remains motionless, check the integrity and reliability of the connection of the vacuum booster hose to the fitting on the engine intake pipe..
3. …and with the booster. Replace or repair the faulty hose. If the hose is in good condition, the vacuum booster must be replaced (see Replacing the brake booster).
Note: The vacuum booster hose is made in one piece with the check valve. Check its functionality (see Checking the operation of the brake booster). If the check valve is faulty, replace the vacuum booster hose assembly.
If braking is accompanied by beating and pulsation of the brake pedal, you should first check the condition of the front disc brakes.
4. After jacking up the car, remove the front wheels one by one and inspect the brake discs. The thickness of the brake discs with a diameter of 276 and 300 mm must be at least 26.0 mm.
Note: Depending on the configuration, Opel Astra J vehicles are equipped with front wheel brake mechanisms with brake discs with a diameter of 276 and 300 mm.
The surface of the disc should be flat and smooth on both sides. If the disc surface is rusty in places, which usually happens after a long period of parking with un-dried brakes, try cleaning the working surface with fine sandpaper. If this procedure does not help, you will have to send the discs for grinding or replace them with new ones.
5. Check the mobility of the brake piston. To do this, try to move the piston with a screwdriver. If the piston cannot be moved, it is jammed in the brake cylinder.
Attention! Jamming of the brake cylinder piston leads to constant braking of the corresponding wheel when the pedal is released and skidding of the car when braking.
If braking is accompanied by jerking of the car and creaking in the area of the rear wheels, and during intensive braking the rear part of the car skids, check the condition of the brake mechanisms of the rear wheels.
Note.
- Depending on the configuration, Opel Astra J cars are equipped with rear wheel brake mechanisms with brake discs with a diameter of 268 and 292 mm.
- Check the thickness of the disc in the same way as you did for the front brake (see point 4); the thickness of brake discs with a diameter of 268 and 292 mm should be at least 12.0 mm.
Check the mobility of the parking brake drive; the cable and drive lever should move freely.
Note: The parking brake operates the rear brakes via cables that connect the parking brake lever and the brake shoe control mechanisms. Many drivers try to use the parking brake as little as possible to extend its "life", and achieve the opposite result. If you do not use the parking brake, dirt and moisture stagnate in the cable sheaths, the cables become covered with rust, stop moving and break. Therefore, use the parking brake when necessary, but do not forget to adjust its drive from time to time (see Adjusting the parking brake drive).
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