Vacuum Brake Booster: Adjustments

BOOSTER PUSH ROD CLEVIS ADJUSTMENT
Install push rod clevis so that measurement "a" is obtained and torque nut to specification.

Tightening Torque:
(a): 26 Nm (2.6 kg-m, 19.0 ft. lbs.)
Length:
"a": 126.1 -127.1 mm (4.96 - 5.00 inch)





INSPECTION /ADJUSTMENT OF CLEARANCE BETWEEN BOOSTER PISTON ROD AND MASTER CYLINDER PISTON ADJUSTMENT
The length of booster piston rod is adjusted to provide specified clearance "a" between piston rod end and master cylinder piston.





- Before measuring clearance, push piston rod several times so as to make sure reaction disc is in place.
- Keep inside of booster at atmospheric pressure for measurement.

1) Set special tool (A) on master cylinder and push pin until contacts piston.

Special Tool
(A): 09950-96010





2) Turn special tool upside down and place it on booster. Adjust booster piston rod length until rod end contacts pin head.

Special Tool
(A): 09950-96010

Clearance "b": 0 mm (0 inch)





3) Adjust clearance by turning adjusting screw of piston rod.

Special Tool
(F): 09952-16010





Reference
When adjusted as above, its negative pressure is applied to booster with engine at idle, piston to piston rod clearance "a" should become above.

Clearance "a ":
SE series 2-door vehicle without Antilock Brake System (ABS): Other SE series vehicles: SE series:
0.25 - 0.5 mm (0.010 - 0.020 inch)
0.14 - 0.35 mm (0.006 - 0.014 inch)
0.14 - 0.35 mm (0.006 - 0.014 in..)

INSPECT BOOSTER OPERATION
There are two ways to perform this inspection, with and without a tester. Ordinarily, it is possible to roughly determine its condition without using a tester.

NOTE: For this check, make sure that no air is in hydraulic line.

INSPECTION WITHOUT TESTER
Check Air Tightness
1) Start engine.
2) Stop engine after running for 1 to 2 minutes.





3) Depress brake pedal several times with the same load as in ordinary braking and observe pedal travel. If pedal goes down deep the first time but its travel decreases as it is depressed the second and more times, air tightness is obtained.





4) If pedal travel doesn't change, air tightness isn't obtained.

NOTE: If defective, inspect vacuum lines and sealing parts, and replace any faulty part.

When this has been done, repeat the entire test.





Check Operation
1) With engine stopped, depress brake pedal several times with the same load and make sure that pedal travel doesn't change.





2) Start engine while depressing brake pedal. If pedal travel increases a little, operation is satisfactory. But no change in pedal travel indicates malfunction.





Check Air Tightness Under Load
1) With engine running, depress brake pedal. Then stop engine while holding brake pedal depressed.





2) Hold brake pedal depressed for 30 seconds. If pedal height does not change, condition is good. But it isn't if pedal rises.