Brake Booster: Installation

WARNING: This page is about a different car, the 2014 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Check and adjust the operating rod of the vacuum booster assembly.
1. Measure the length between the vacuum booster assembly mounting surface and clevis pin hole.
2. If it is not within the specification, loosen the lock nut, rotate the vacuum booster assembly operating rod to adjust the rod length.
  Specification L:
  
  136.3 mm (5.37 in)
  
  Fig 1: Identifying Vacuum Booster Mounting Surface And Clevis Pin Hole Length
  Courtesy of SUBARU OF AMERICA, INC.

Install the vacuum booster assembly.

CAUTION:

Replace the clevis pin with a new part, and apply a thin coat of grease to the clevis pin.
Preparation items:

Grease: NIGTIGHT LYW No. 2 grease or equivalent

When installing the master cylinder assembly, replace the seal sub assembly with a new part, and install it to the vacuum booster assembly.

Courtesy of SUBARU OF AMERICA, INC.

Apply grease to the entire inner diameter of the vacuum booster assembly.
Preparation items:

Grease: An item contained in the seal kit (fluorine grease) or equivalent
Apply grease to the entire outer diameter of the seal sub assembly.
Preparation items:

Grease: An item contained in the seal kit (fluorine grease) or equivalent
Apply grease to the entire inner diameter of the seal sub assembly.
Preparation items:

Grease: An item contained in the seal kit (silicone grease) or equivalent

Apply grease to the entire circumference on the piston rod of the master cylinder assembly.

Preparation items:

Grease: An item contained in the seal kit (silicone grease) or equivalent

CAUTION:

Apply fluorine grease to the entire circumference. Areas where application was missed may cause rust.
Be careful not to mix up application locations of each grease.

Courtesy of SUBARU OF AMERICA, INC.

(a)	Master cylinder ASSY
(b)	Piston rod portion
(c)	Seal sub ASSY
(d)	Vacuum booster ASSY
(e)	Fluorine grease application location
(f)	Silicone grease application location

Courtesy of SUBARU OF AMERICA, INC.

(a)	Vacuum booster ASSY inner diameter (entire circumference)
(b)	Seal sub ASSY outer diameter (entire circumference)
(c)	Grease application location

Install the vacuum booster assembly.
Tightening torque:

18 N.m (1.8 kgf-m, 13.3 ft-lb)

Install each part in the reverse order of removal.
Tightening torque:

Master cylinder assembly: 13 N.m (1.33 kgf-m, 9.6 ft-lb)

Operating lock nut: 22 N.m (2.24 kgf-m, 16.2 ft-lb)

Knee airbag module: 7.5 N.m (0.76 kgf-m, 5.5 ft-lb)
Turn and tighten the flare nut (b) by hand while pressing the brake pipe (a) toward the master cylinder assembly side.
CAUTION: Be careful not to make scratches or other damage to the inside surface of the brake pipe flare.

Tightening torque:

Brake pipe flare nut: 19 N.m (1.94 kgf-m, 14.0 ft-lb)

Fig 2: Tightening Flare Nut
Courtesy of SUBARU OF AMERICA, INC.
Install the air conditioner pipe. < Ref. to AIR CONDITIONING UNIT , COMPONENT, General Description. >
Bleed air from the brake system. < Ref. to PROCEDURE , Air Bleeding. >
Perform a road test to make sure the brakes do not drag.