Genuine Audi 100 Brake Booster

Audi 100 Brake Booster Parts and Q&A

• Pressure Metering Valve
  443-614-151-B
  Q: How to test and replace the Brake Booster servo unit on Audi 100?

  A:

  To test the operation of the brake booster, depress the footbrake several times to exhaust the vacuum, then start the engine while keeping the pedal firmly depressed; there should be a noticeable give in the brake pedal as the vacuum builds up. Allow the engine to run for at least two minutes, then switch it off. If the brake pedal feels normal upon depression but becomes firmer with each subsequent application, the brake booster is functioning correctly. If not, inspect the brake booster check valve and, for diesel and 2.3 litre petrol engine models, check the Vacuum Pump. If the brake booster still fails to operate satisfactorily, it must be renewed as repairs are not possible. For removal, new mounting nuts will be required for refitting. Begin by removing the master cylinder, then carefully ease the vacuum hose connection out from the brake booster without damaging the grommet. Remove the storage compartment panel from the driver's side of the facia and free the relay mounting plate for better access. Unhook the pedal return spring from the brake booster pushrod, withdraw the clevis pin securing the pushrod to the pedal, and remove the nuts securing the brake booster/pedal mounting bracket to the bulkhead. Maneuver the brake booster out of position, recovering and examining the gasket for wear or damage. For refitting, check that the distance from the centre of the pushrod clevis pin bore to the brake booster master cylinder mating surface is 230 ± 0.5 mm, adjusting if necessary. Ensure the mating surfaces are clean, fit the gasket to the rear of the brake booster, and maneuver it into position. Inside the vehicle, ensure the pushrod is correctly engaged with the pedal, then fit and tighten the new mounting bracket nuts. Apply a smear of multi-purpose grease to the clevis pin, align the pedal with the pushrod, insert the pin, secure it with the retaining clip, and hook the pedal return spring back into position. Relocate and securely tighten the relay mounting plate, reattach the storage compartment panel, ease the vacuum hose end fitting into position in the brake booster, and finally, refit the master cylinder and bleed the complete hydraulic system.
• Pressure Metering Valve
  443-614-151-H
  Q: How to remove and test the Brake Booster vacuum hose and valve on Audi 100?

  A:

  To eliminate the vacuum hose, it is necessary to loosen the connection out of the servo unit being careful not to destroy the grommet. Back along the hose, and loosen it off all the retaining clips, and record the proper route to take. Unscrew the retaining clip(s) and unconnect the vacuum hose with the manifold or Vacuum Pump and take it out of the vehicle. Test To test, check the vacuum hose to see if it has been damaged and replace it. One can test the valve by blowing through it in each of the directions, the air must flow through only in one direction when blown on the end of the servo unit. Replace the valve in case it does not pass this test. In addition, inspect the rubber sealing grommet and hose(s) connecting the main hose with the manifold / pump whether there is any damage or wear and tear and replace as necessary. To refit, make sure that the sealing grommet is aligned correctly in the servo unit, and then very carefully slot the vacuum hose end fitting in without disturbing or breaking the grommet. Make certain that the hose is properly positioned, attached to the pump/manifold, and make certain that the retaining clips are tight. Lastly, turn on the engine and test the connection between the check valve and the servo unit and find any air leaks.