Honda Acty — Brakes
Front disc, rear drum, brake fluid specification, master cylinder, and full bleed procedure.
System Overview
Master Cylinder
The brake master cylinder is located under the driver's seat, mounted against the firewall. To access it, tip the driver's seat forward — it pivots at the front hinge. The reservoir cap is visible on top. Inspect the fluid level and condition at every oil change. Fluid that has darkened significantly or that has visible moisture contamination should be flushed and replaced.
Front Disc Brakes
The front brakes are single-piston sliding-caliper disc brakes. Pad replacement follows standard automotive procedure: remove the caliper bolts, slide the caliper off the rotor, compress the piston, install new pads, and reassemble. Do not allow the caliper to hang by the brake line — support it with a wire hook or set it on a flat surface.
Inspect rotor thickness and surface condition whenever the pads are replaced. Grooved or heat-cracked rotors should be replaced rather than resurfaced — the rotors are inexpensive and thin-wall resurfacing leaves little safety margin.
Rear Drum Brakes
The rear drums are straightforward leading/trailing shoe drums. Shoe replacement requires removing the rear wheels, pulling the drums, and carefully noting the orientation of the existing shoe springs before disassembly — photograph everything before you start. Adjustment is via a self-adjusting mechanism inside the drum; manually back off the adjuster to allow the drum to slide over new, taller shoes.
Brake Fluid
| Brand | Part Number | Notes / Info |
|---|---|---|
| Honda | DOT 3 | OEM spec — use DOT 3 or DOT 4 |
| Prestone | AS800Y | DOT 3 brake fluid — widely available |
| ATE | DOT 4 | Higher dry boiling point — suitable upgrade |
Brake fluid is hygroscopic — it absorbs moisture from the air over time, which lowers its boiling point and accelerates internal corrosion. Flush the entire system with fresh fluid every two years regardless of appearance.
Bleeding Procedure
Bleed brakes in the following order, starting farthest from the master cylinder and working closer:
- Right Rear (RR) — farthest from master cylinder, bleed first
- Left Rear (LR)
- Right Front (RF)
- Left Front (LF) — closest to master cylinder, bleed last
Two-Person Bleed Method
- Fill the master cylinder reservoir to the MAX line. Keep it topped up throughout the procedure to avoid introducing air.
- Attach a clear hose to the first bleed nipple and submerge the other end in a jar with a small amount of clean brake fluid.
- Have an assistant press and hold the brake pedal firmly.
- Open the bleed nipple approximately one-quarter turn. Fluid (and any bubbles) will flow into the jar.
- Close the nipple before the assistant releases the pedal — releasing the pedal with the nipple open draws air back into the system.
- Repeat until fluid flowing out is clear and bubble-free, then move to the next wheel.
- Check and top up the reservoir frequently during the process.
One-Person Bleed (Pressure or Vacuum Bleeder)
A pressure bleeder attached to the reservoir or a vacuum bleeder at each nipple allows a single person to bleed brakes without an assistant. Follow the tool manufacturer's instructions, but maintain the same bleed order: RR, LR, RF, LF.