Checking the brake booster (VW Golf 1)

With the engine off, press the brake pedal several times until it stops and hold it in the extreme position.

Start the engine. If the booster is functioning properly, the pedal may move a little more.

If the pedal does not go down, you need to check: perhaps the vacuum hose leading from the intake manifold to the brake booster is not tight. Or there is a defect in the check valve of the vacuum hose or in the rubber ring between the main brake cylinder and the booster. Perhaps the booster membrane is damaged.

To check the check valve, remove the vacuum hose near the brake booster.

You need to blow, but not suck.

The check valve is only available for sale together with the corresponding vacuum hose.

The arrow on the valve should point towards the inlet pipe.

To replace a damaged rubber ring between the master cylinder and the booster, remove the cylinder (see section "Removal the master brake cylinder").

The defective brake booster is replaced as a set.