2. Servo booster failure can be judged by the additional force required to actuate the brakes. Servo amplifier testing should be carried out by a specialist with the necessary equipment. The only thing you can do yourself is to replace the servo air filter (Recommended to be done every 2 years) and one way valve.
Air filter replacement
3. When replacing the filter, the servo amplifier can be left in place. The air filter is located around the pusher and is covered with a rubber boot on the rear wall of the servo amplifier.
4. Remove the clamp that secures the hinge pin at the junction of the pusher with the brake pedal. Remove the rubber boot and filter retainer. Pull out the old filter using a suitable hook.
5. Because a new filter cannot pass through the end of the pusher, make a diagonal cut on the filter with a sharp knife so that you can unscrew the edges of the cut and pass the filter through the pusher. Install the filter, its retainer and cover. Reinstall the pivot pin and secure it with a new clip.
One way valve replacement
6. Loosen the clamp and disconnect the vacuum hose from the one way valve on the front of the servo. After that, you can pull the valve out of the sealing rubber sleeve. It is advisable to replace the bushing with a new one, regardless of its condition, and if it is worn or cracked, replacement becomes mandatory. Install a new valve into the sleeve. To facilitate installation, you can use brake fluid as a lubricant.