Brake Master Cylinder Reassembly

  • Clean all the parts in brake fluid and air dry; blow out all passages with compressed air.
  • Before reassembling, check that all the parts are free of dust and other foreign particles.
  • Replace parts with new ones whenever specified to do so.
  • Use only genuine DOT 3 or DOT 4 Honda Brake Fluid. Non-Honda brake fluid can cause corrosion and shorten the life of the system.
  • Do not mix different brands of brake fluid as they may no be compatible.
  • Replace the master cylinder if the bore is damaged or worn. Do not hone or attempt to refinish the bore.
  • Coat the piston cups, pressure cup and master cylinder bore with clean brake fluid.
  • Use recommended greases in the master cylinder seal set.
  • The illustrations show LHD/ABS type.

1.Install the reservoir seal in the groove of the reservoir cap.

2.Install the strainer, assembled reservoir cap on the reservoir tank.


3.Coat the cups (A) of a new primary piston (B) with clean brake fluid, then install the primary piston into the master cylinder.

NOTE: Check that the valve stem (C) moves smoothly by lightly pushing it through the slot in the piston.


4.Coat the cup (A) of a new secondary piston (B) with clean brake fluid, and apply the silicone grease to the piston surface (C).


5.Apply the rubber grease to a new piston guide (A), an O-ring (B) and a secondary cup (C).


6.Install the primary piston (A), secondary piston (B) and piston guide (C) into the master cylinder. Make sure the direction of piston guide.

NOTE: Install the primary piston so the slot (D) in the piston aligns with the stop pin hole in the master cylinder.


7.Align the slot (A) in the primary piston with the stop pin hole (B) by pushing the secondary piston in, and install the stop pin (C).


8.Apply the rubber grease to the surface of the new reservoir grommets (D), then install the grommets and reservoir union (E) to the master cylinder.

9.Install the new snap ring (A) while pushing in the secondary piston (B). Be careful not to scratched damage on the piston surface with the snap ring edges.


10.Install the reservoir (A) and the reservoir tank hose (B) to the reservoir union (C).

  • Align the ‘‘[utri]'' mark (D) on the reservoir and reservoir union with the paint mark (E) on the hose.
  • Position the direction of the clamp (F).


11.Apply the silicone grease to a new rod seal, and install the seal onto the master cylinder.