Checking the brake booster (Renault 19)

1. With the engine off, press the brake pedal all the way down several times and hold it in this position.

2. Start the engine. If the brake booster is working properly, the pedal should move forward a little more.

3. If the pedal does not go down, then check: is the low-pressure hose running from the intake pipe or, respectively, from the vacuum pump to the brake booster sealed?; is the vacuum pump working; is the low pressure hose check valve OK, the rubber ring between the brake master cylinder and the brake booster; whether the booster membrane and the air filter on the brake booster pushrod are damaged.

4. To check the check valve, remove the low pressure hose from the brake booster.

5. A normally functioning valve can be blown out, but air cannot be drawn through it.

6. To replace the damaged rubber ring between the brake master cylinder and the brake booster, remove the brake master cylinder.

7. The additional air filter can be replaced. To do this, remove the old air filter from the brake booster pushrod with a wire hook. Cut the new filter to the middle and put it around the pushrod in place. Make sure that the filter is tightly placed around the pushrod, otherwise unfiltered air may enter the brake booster.

8. A faulty brake booster must be replaced. The booster cannot be repaired.

[Source link is located on: renaultbook]