Genuine Mitsubishi Lancer Brake Booster

Mitsubishi Lancer Brake Booster Parts Questions & Experts Answers

• Power Booster
  MR527618
  Q: How to check the operation and adjust the brake booster and check valve on Mitsubishi Lancer?

  A:

  In order to test the operation, with the engine stopped, depress the brake pedal several times in order to use up all the vacuum from the booster and the vacuum reservoir. Press the brake pedal down firmly and start the car engine. A distinct downward movement of the brake pedal indicates that the brake booster is functioning properly. If not, the vacuum system is inoperative. If the vehicle's clutch pedal continues to fall away, the hydraulic system may be faulty. Ensure the brake pedal is fully released, start the engine and run it at medium speed, then stop the engine. Allow the car to sit for 1-2 minutes, and press the brake pedal two or three times. If no vacuum assistance is felt, there is a leak in the vacuum system or defective check valve. To check the brake booster, first remove the hose and check valve and start the engine. The booster should have vacuum at it and in the check valve. When the engine is not running, press down on the footbrake several times until all vacuum is expelled. Release the clamp over the hose and detach the vacuum hose from the inlet manifold. To make sure air is not blowing through the hose, you would blow into it. Next suck on the vacuum hose to ensure air is flowing through. If either test indicates a fault, renew the check valve. To renew the check valve, depress the brake pedal several times to deplete all vacuum, then release clamps, and disconnect the hose from the inlet manifold and brake booster, noting the installed direction of vacuum hose. As an assembly which must be renewed is the vacuum hose check valve. The reversibility of removal allows installation (ensuring the vacuum hose is installed in the direction noted and hose clamps secure). In order to remove and fit the booster, the lower dash panel beneath the steering column must first be removed. To do this, remove the retaining clip and withdraw the clevis pin from the brake pedal. Note the washer's installed position. When the clevis is installed, mark its position, loosen the locknut and remove the clevis by turning it anticlockwise. Take off the brake booster retaining nuts and on the manual transaxle CE models, remove the clutch master cylinder. Remove the clips that secure the vacuum hose and detach the hose from the inlet manifold and brake booster fittings. Detach the Brake Master Cylinder from the car, moving the brake pipes to one side, and maneuvering the brake booster from the engine compartment without damaging the pipes. Take out the gasket on the brake booster firewall if damaged. Installation reverses the removal, being sure the vacuum hose is not leaking or collapsed, and all connections are secure. If it's removed, the brake booster must have a new gasket fitted. Reinstall the clevis pin, washer, and retaining clip as shown in the illustration. If a new booster is installed, the pushrod setting should be factory set; otherwise, it should be checked. The brake master cylinder is installed, and the brakes bled. For CE manual transaxle models, the clutch master cyl is installed and bled. To check and reset the pushrod setting, remove the brake master cylinder and for CE models measure the distance from the mounting flange to the end of the master cylinder and record this as dimension B. With the vernier gauge, measure the distance from the end of the master cylinder to the bottom of the hole in the piston. This is dimension C. Record the pushrod extension from the surface of the master cylinder mounting on the front of the brake booster as dimension A (CE models only: measure and check dimensions against CG and CH specifications). For CE models, use the dimensions in the equation: Pushrod clearance = (C - B) - A, and check the dimensions with specifications. If necessary, with pliers, hold the knurled portion of the pushrod and adjust the pushrod length until dimension A when plugged into the formula gives the specified clearance.