Master Cylinder Disassembly/Assembly

Exploded View Of Compact 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.

Fluid Level Sensor Switch:

Unlocking Switch Tabs:

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.

Removing/Installing Reservoir Spring Pins:

NOTE: In order to remove the proportioner valve caps it may be necessary to remove the reservoir assembly.

Reservoir Assembly
- Clamp flange on master cylinder in a vise, then drive out spring pins using 1/8 inch punch.
- Remove reservoir by pulling straight up, away from cylinder body. Remove O-rings.
- Inspect reservoir for cracks or deformation and replace if found.

Proportioner Valve Cap Assemblies:

Proportioner Valve Assemblies
- Remove proportioner valve cap assemblies.
- Remove "0" rings.
- Remove springs.
- Remove proportioner valve pistons.

CAUTION: Use needle nose pliers with care not to scratch or otherwise damage piston stems.

- Remove proportioner valve seals from pistons.
- Inspect proportioner valve pistons for corrosion, or deformation and replace if found.

CAUTION: Do not damage piston or cylinder wall.

5. Depress primary piston and remove retainer.
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. 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 O-rings, then install into reservoir grooves. Ensure O-rings are properly seated.

Installing Reservoir:

2. Install reservoir onto master cylinder body by pressing straight down, then drive in spring pins to retain reservoir.
3. Install new lubricated seals and spring retainer on secondary piston.
4. Install spring and secondary piston assembly into cylinder.
5. Install lubricated primary piston. Depress primary piston into cylinder, then install retainer.
6. Install fluid level switch and proportioner valve assembly, if equipped.

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 Assemblies
- Clean all parts in clean, denatured alcohol and dry with unlubricated compressed air.
- Lubricate new "0" rings and proportioner valve seals with silicone grease supplied in repair kit. Also lubricate stem of proportioner valve pistons.
- Install new seals on proportioner valve pistons with seal lips facing upward toward cap assembly.
- Install proportioner valve pistons and seals in master cylinder body.
- Install springs in master cylinder body.
- Install new "0" rings in grooves in proportioner valve cap assemblies.
- Install proportioner valve caps in master cylinder body and torque to 27 Nm (20 lbs. ft.).
- Install reservoir assembly, if removed.

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