Overhaul

BRAKE MASTER CYLINDER

Disassembly and Assembly


COMPONENTS












DISASSEMBLY


CAUTION:
While working, cover primary piston rod with cloth to prevent it from being damaged.





1.Secure flange of cylinder body in vise as shown.

CAUTION:
- Use copper plate or cloth to cover flange when securing in vise.
- When securing master cylinder assembly in a vise, be sure not to over-tighten.





2.Using a pin-punch [commercial service tool: diameter approx. 4
mm (0.16 in)], remove pin from reservoir tank.
3.Remove master cylinder assembly from vise.
4.Remove reservoir tank and grommet from cylinder body.





5.While pushing primary piston, remove piston stopper through secondary tank boss hole in the cylinder body.










6.Remove snap ring while pushing primary piston.

CAUTION:
Be careful not to pop out piston.
7.Holding rod of primary piston, remove primary piston assembly, plate and guide assembly by pulling straight to prevent piston cup from being caught by the inner wall of cylinder.
8.Remove plate and guide assembly from primary piston.

CAUTION:
Be careful not to damage rod from the inner wall of plate.





9.Tap flange using a soft block such as wood, and carefully pull secondary piston assembly straight out to prevent cylinder inner wall from being damaged.

INSPECTION AFTER DISASSEMBLY

Cylinder Body
- Check the inner wall of cylinder for damage, wear, corrosion, and pin holes. Replace cylinder body if necessary.

ASSEMBLY


CAUTION:
- Never use mineral oils such as kerosene or gasoline during the cleaning and assembly processes.
- Make sure that there is no foreign material such as dirt and dust on the inner wall of cylinder, piston, and piston cup. Be careful not to damage parts with a service tool when assembling.
- Do not drop parts. If a part is dropped, do not use it.





1.Apply brake fluid to the inner wall of cylinder body, primary piston assembly and secondary piston assembly.
2.Insert secondary piston and primary piston assembly into cylinder body in this order.

CAUTION:
- Pay attention to the orientation of piston cup, and insert straight to prevent cup from being caught by the inner wall of cylinder.
- Always replace inner kit as a set.





3.Set the slit of secondary piston towards the piston stopper mounting hole of cylinder body while pushing in the primary piston. Then install the piston stopper through the slit of secondary piston.





4.Insert plate and guide assembly into cylinder body.

CAUTION:
- Be careful not to damage rod of primary piston.
- Pay attention to the orientation of guide assembly.
- Do not drop O-ring.
- Be careful the guide and/or plate are not inserted at an angle to cylinder inner wall.





5.Be careful not to damage rod of primary piston with the cloth.
Then insert snap ring to cylinder body while pushing primary piston.

CAUTION:
Make sure that snap ring is securely engaged in cylinder body inner diameter groove.
6.Apply brake fluid to a grommet, and press it into reservoir tank to install.





7.Install reservoir tank to cylinder body.

CAUTION:
Pay attention to the orientation of reservoir tank. Make sure reservoir tank is fully seated on master cylinder.





8.Secure flange of cylinder body in vise as shown.

CAUTION:
- Use copper plate or cloth to cover flange for securing in the vise.
- When securing master cylinder assembly in a vise, be sure not to over-tighten.
- Be sure to secure the flange part with the brake tube installation side of cylinder body facing up (chamfered pin insert hole of cylinder body facing up).





9.Using a pin punch [commercial service tool: diameter approx. 4
mm (0.16 in)], insert the reservoir tank pin into the pin hole.