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 fluid level switch and proportioner valve assemblies, if equipped.

Unlocking Switch Tabs:

Fluid Level Sensor Switch:

Fluid Level Sensor Switch
- Remove electrical connector from fluid level sensor switch.
- Remove fluid level sensor switch using needle nose pliers to compress switch locking tabs at inboard side of master cylinder.

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 retainer.

CAUTION: Do not direct compressed air into proportioners (2 or 4), to remove piston assemblies since this will damage proportioners.

6. While directing low pressure compressed air into top outlet port at blind end of bore (all other outlet ports plugged), remove primary and secondary pistons.
7. Remove spring retainer and seals from secondary piston.

Removing Reservoir:

CAUTION: Do not clamp across master cylinder body.

8. Clamp flange on master cylinder body in vise.

CAUTION: Do not attempt to remove quick take-up valve from the body. The valve is not serviceable separately.

9. Remove reservoir using a pry bar.

NOTE: Use wooden block between cylinder body and reservoir if necessary, to provide better pry bar leverage.

10. Remove reservoir grommets.
11. Inspect master cylinder bore for corrosion.

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

Assembly

NOTE: Clean all parts not included in repair kit with denatured alcohol then dry with compressed air.

1. Lubricate new reservoir grommets, then install into reservoir grooves. Ensure grommets are properly seated.

Installing Reservoir:

2. Thoroughly lubricate reservoir bayonets with clean brake fluid.
3. Install reservoir onto master cylinder body using rocking motion.
4. Install new lubricated seals and spring retainer on secondary piston.
5. Install spring and secondary piston assembly into cylinder.
6. Install lubricated primary piston. Depress primary piston into cylinder, then install retainer.
7. Install fluid level sensor switch and proportioners.

Fluid Level Sensor Switch
- Install fluid level sensor switch until locking tabs snap in place.
- Install electrical connector to fluid level sensor switch.

Proportioner Valve Assembly
- Lubricate new 0-rings and external proportioner valve threads with clean brake fluid.
- Install new 0-rings on proportioner valve assemblies.
- Install proportioners into master cylinder body and torque to 33 Nm (24 ft.-lbs.).

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