Nissan 47210-85E02 MASTERVACUUM Assembly-Brake

To perform an operating check, depress the brake pedal several times with the engine off to ensure there's no change in the pedal reserve distance, then start the engine while depressing the pedal; if it goes down slightly, operation is normal. For an airtightness check, start the engine and turn it off after one or two minutes, then depress the brake pedal slowly several times; if the pedal depresses less each time, the booster is airtight. While the engine is running, depress the brake pedal and stop the engine with the pedal depressed; if there's no change in the pedal reserve travel after holding it for 30 seconds, the booster is airtight. To check the output rod length, remove the master cylinder without disconnecting the lines, apply about 20 in-Hg of vacuum to the brake booster, push in on the output rod with approximately 4-1/2 pounds of force, measure the length of the output rod from the top to the master cylinder mounting surface, and compare it to the specified length; if outside specifications, replace the booster. For replacement, remove the air cleaner and duct if necessary for access, disconnect the vacuum hose from the booster, remove the under-dash panel, locate and detach the pushrod clevis from the brake pedal, remove the clevis pin, and take out the four nuts and washers holding the brake booster to the firewall, then slide the booster straight out. Installation is the reverse of removal, but measure the distance between the power brake booster and the hole in the clevis before installing the assembly; if the measurements differ, adjust the clevis to the specified length before tightening the nut.