Master Cylinder Disassembly/Assembly

Exploded View Of Master Cylinder Assembly:

Disassembly
1. Remove master cylinder from vehicle.
2. Remove reservoir cover and diaphragm. Discard old brake fluid in reservoir.
3. Inspect cover and diaphragm. Replace if cut, cracked or deformed.
4. Remove failure warning switch and proportioners, if equipped.

Failure Warning Switch:

Failure Warning Switch
- Remove electrical lead.
- Remove failure warning switch.
- Remove 0-ring (OEM switch may not include 0-ring).

Proportioner Valve Assemblies:

Proportioner Valve Assemblies
- Remove proportioner valve assemblies.
- Remove 0-rings.

CAUTION: Do not damage piston or cylinder wall.

5. Depress primary piston and remove lock ring.
6. Plug primary fluid outlet (outlet nearest to cowl when master cylinder is installed), then apply compressed air into secondary fluid outlet to remove primary and secondary pistons.
7. Remove spring retainer and seals from secondary piston.
8. Remove switch piston assembly.

Switch Piston Assembly:

Switch Piston Assembly
- Remove failure warning switch (if not previously removed).
- Remove allen head plug and 0-ring.
- Remove switch piston using needle nose pliers.

Removing Master Cylinder Reservoir:

9. Clamp master cylinder in a vise, then remove reservoir using a pry bar. Remove reservoir grommets.

CAUTIONS:
^ Do not clamp on master cylinder body, instead clamp on mounting flange.
^ Do not remove quick take-up valve from body. The valve is not serviceable separately.

10. Inspect master cylinder bore for corrosion.

NOTE: Do not use abrasive material on master cylinder bore. Replace if bore is corroded.

Assembly
1. Clean all parts in clean denatured alcohol. Dry with compressed air.
2. Lubricate new reservoir grommets with brake fluid, then press grommets into master cylinder body. Ensure grommets are properly seated.

Installing Reservoir:

3. Lay reservoir upside down on flat, hard surface. Press master cylinder body onto reservoir using rocking motion.
4. Lubricate new seals with brake fluid and install on secondary piston.
5. Install spring, spring retainer and secondary piston assembly into cylinder.
6. Lubricate seals then install primary piston. Depress primary piston into cylinder, then install lock ring.
7. Install switch piston, failure warning switch, and proportioners, if equipped.

Switch Piston
- Install switch piston into master cylinder body.
- Install O-ring on plug.
- Plug into master cylinder body and torque to 4.5-16 Nm (40-140 in. lb.).
- Install failure warning switch.

Failure Warning Switch
- Install new 0-ring on failure warning switch.
- Install switch assembly and torque to 1.7 - 5.6 Nm (15 - 50 in. lb.).
- Install electrical lead.

Proportioner Valve Assemblies
- Install new 0-ring on proportioner valve assemblies.
- Install proportioners into master cylinder body and torque to 24 - 40 Nm (18-30 ft. lb.).

8. Fit diaphragm into reservoir cover, then install cover onto reservoir.
9. Install master cylinder in vehicle.