SECTION 4B
MASTER CYLINDER
SPECIFICATIONS
Fastener Tightening Specifications
Application | N•m | Lb-Ft | Lb-In |
Brake Lines | 16 | 12 | - |
Master Cylinder Attaching Nuts | 18 | 13 | - |
Proportioning Valves | 40 | 30 | - |
Bleeder Valves | 6 | - | 53 |
MAINTENANCE AND REPAIR
ON-VEHICLE SERVICE
Master Cylinder Assembly
Removal Procedure
- Disconnect the electrical connector from the reservoir.
- For vehicles with the ABS braking system, disconnectthe brake lines from the master cylinder body.
- For vehicles with the non-ABS braking system, disconnectthe brake lines from the proportioning valves.
- For vehicles with the manual transaxle, disconnectthe clip to the clutch hose connection at the mastercylinder.
- Plug the opening to the brake lines to prevent fluidloss and contamination.
- Remove the attaching nuts from the power booster.
- Remove the master cylinder assembly.
- Remove the seal from the booster housing. Discardthe seal.
- Drain the brake fluid.
Installation Procedure
- Install the master cylinder assembly with the new attachingnuts.
- Install the new seal to the booster housing.
Tighten
Tighten the master cylinder attaching nuts to 18 N•m(13 lb-ft)..
- For vehicles with the ABS braking system (asshown), connect the brake lines to the cylinder body.
- For vehicles with the non-ABS braking system, connectthe brake lines to the proportioning valves.
Tighten
Tighten the brake lines to 16 N•m (12 lb-ft).
- For vehicles with the manual transaxle, connect theclip to the clutch hose connection at the master cylinder.
- Connect the electrical connector on the reservoir.
- Add brake fluid.
- Check for leaks and recheck the fluid level.
- Bleed the brake system. Refer to Section 4A, HydraulicBrakes.
Brake Fluid Reservoir
Removal Procedure
Important : Remove the reservoir only when replacing adamaged or a leaking reservoir.
- Disconnect the electrical connector from the reservoir.
- For vehicles with the manual transaxle, disconnectthe clip to the clutch hose connection at the mastercylinder.
- Gently pry upward with a screwdriver to release thereservoir.
- Tilt the reservoir and pull it upward in order to removeit.
- Remove the reservoir seals from the master cylinderbody.
Installation Procedure
- Lubricate the new seals with clean brake fluid. Installthe seals into the cylinder body.
- Install the reservoir on the master cylinder body. (TheABS system is shown.)
- For vehicles with the manual transaxle, connect theclip to the clutch hose connection at the master cylinder.
- Add brake fluid.
- Raise and suitably support the vehicle.
- Bleed the braking system. Refer to Section 4A, Hydraulic Brakesor Section 4F, Antilock Brake System.Bleed the clutch master cylinder. Refer to Section 5C, Clutch.
- Lower the vehicle.
- Connect the reservoir electrical connector.
Prorortilning Valve
Removal Procedure
- Disconnect the brake lines from the proportioningvalves.
- Remove the valves from the master cylinder body.
Installation Procedure
Important : Since these valves are adjusted in pairs tothe correct control range, they must be replaced in pairs.
- Install the proportioning valves to the cylinder body.
Tighten
Tighten the proportioning valves to 40 N•m (30 lb-ft).
- Connect the brake lines to the valves.
Tighten
Tighten the brake lines to 16 N•m (12 lb-ft).
- Raise and suitably support the vehicle.
- Bleed the braking system. Refer to Section 4A, Hydraulic Brakesor Section 4F, Antilock Brake System.
- Lower the vehicle.
UNIT REPAIR
Master Cylinder Overhaul
Disassembly Procedure
- Remove the master cylinder. Refer to "Master Cylinder Assembly" in this section.
- Remove the brake fluid reservoir. Refer to "Brake Fluid Reservoir" in this section.
- Remove the seal ring from the cylinder bore.
Notice : When removing the retaining ring, avoid damagingthe piston or the cylinder wall.
Important : A welding rod or its equivalent can be usedin a compensating port to keep the piston pressed down.
- Remove and discard the retaining ring from the cylinderbody using a suitable screwdriver. (The non-ABSmaster cylinder body is shown.)
- Remove the primary piston. (The ABS master cylinderbody is shown.)
- Carefully remove the secondary piston assembly andthe spring from the master cylinder bore.
Assembly Procedure
Notice : Do not use abrasives in the master cylinderbore. Abrasives can damage the bore.
Important : Rubber parts and retaining rings must bediscarded and replaced with new parts
- Clean all parts with denatured alcohol or clean brakefluid. Dry the parts with compressed air.
- Inspect the master cylinder bore for scoring or corrosion.If scoring or corrosion is evident, replace themaster cylinder body.
- Lubricate the master cylinder bore with clean brakefluid. (The non-ABS master cylinder is shown.)
- Carefully insert the secondary piston assembly boreuntil the secondary piston contacts the base of thecylinder body. Use a wood or a plastic drift, if necessary.
- Insert the primary piston.
- Press the pistons into the cylinder bore using awooden or a plastic drift.
Notice : When installing the new retaining ring, take carenot to damage the cylinder bore.
- Insert the new retaining ring into the groove in thecylinder bore. (The non-ABS cylinder body isshown.) Remove the welding rod.
- Move the pistons backward and forward after installationto check for free movement.
- Lubricate the seal ring and insert the seal on theshaft into the cylinder bore. The open side must faceoutward until the seal rests on the piston.
- Install the brake fluid reservoir to the master cylinder.Refer to "Brake Fluid Reservoir" in this section.
- Install the master cylinder assembly. Refer to Master Cylinder Assemblyin this section
- Raise and suitably support the vehicle.
- Bleed the braking system. Refer to Section 4A, Hydraulic Brakesor Section 4F, Antilock Brake System.
- Lower the vehicle.
GENERAL DESCRIPTIONAND SYSTEM OPERATION
Master Cylinder
The master cylinder is designed for use in a diagonalsplitsystem. One front and one diagonally opposite rearbrake are served by the primary piston. The oppositefront and rear brakes are served by the secondary piston.The master cylinder incorporates the functions ofthe standard dual master cylinder, plus a low fluid levelindicator and the proportioning valves in the non-antilockbraking system. The proportioning valves limit the outletpressure to the rear brakes after a predetermined mastercylinder pressure has been reached.
Notice : Do not use lubricated shop air on brake parts,as this may damage rubber components.
Important : - Replace all the components included in the repair kitsused to service this master cylinder.
- Lubricate rubber parts with clean brake fluid to easeassembly.
- if any hydraulic component is removed or disconnected,it may be necessary to bleed all or part of thebrake system.
- The torque values specified are for dry, unlubricatedfasteners.
- Perform all service operations on a clean bench, freefrom all traces of mineral oil.
Proportioning Valves
The proportioning valves limit the outlet pressure to therear brakes on the non-antilock braking system after apredetermined master cylinder pressure has beenreached. This is used when less rear apply force isneeded to obtain optimum braking and is usually foundon disc/drum brake configurations. On ABS-equippedvehicles, refer to
Section 4F, Antilock Brake System.Fluid Level Sensor
The master cylinder is equipped with a fluid level sensor.This sensor will activate the BRAKE light if a low fluidlevel condition is detected. Once the fluid level is corrected,the BRAKE light will go out.
