Ford AT4Z-2005-A
Brake Booster

The service and repair of the vacuum brake booster starts by removing the stoplamp switch and speed control deactivator switch in their uncompressed position using the at-rest brake pedal position since this enables proper bracket rotation for the switches; disregarding this step might damage them. After stopping the stoplamp switch service disconnect the brake booster check valve from its position on the brake booster to stop the master cylinder seal from entering the booster. The brake master cylinder must be taken out while maintaining proper hose assembly routing to safeguard it from surrounding elements which might harm the hose. After disconnecting the vacuum hose and wire harness from their studs you should place them aside. Remove the brake booster push rod pin and clip before disconnecting the push rod from the brake pedal then move forward with the removal of four brake booster nuts that need a torque setting of 23 Nm (17 lb-ft). It is essential to follow the removal process in reverse during installation but never expose the brake pedal to any force while mounting either the stoplamp switch or speed control deactivator switch since these components need to be placed with the booster push rod secured to the brake pedal at zero position to sustain proper adjustment and prevent damage. The brake booster needs an inspection for proper operation.

Servicing the vacuum brake booster begins with removing the stoplamp switch when the brake pedal rests at its position. Maintain compression on the plunger before rotating the bracket. Removing the switch while its plunger is extended will damage the device. The brake booster check valve needs disconnecting from the brake booster before master cylinder seal removal from the booster. The vacuum hose assembly should be directed properly to bypass surrounding components before vacuum hose and wire harness disconnection from their studs to place them aside. The brake booster push rod pin and clip must be removed before detaching the push rod from the brake pedal along with removing the four brake booster nuts which should be tightened to 23 Nm (17 lb-ft) during installation. Put the stoplamp switch together with the attached booster push rod when the brake pedal sits in the at-rest position to ensure proper adjustment and protection of the switch during the installation which follows the removal process in reverse.

Remove the brake booster push rod pin and clip.