Bleeding the Brakes on a 2019 Honda Monkey ABS

Shop parts for a 2019 Honda Monkey ABS Motorcycle.

The Monkey may be small, but its brake hardware is modern: the 2019 ABS model runs hydraulic disc brakes at both the front and rear wheels, backed by an anti-lock braking unit. That means both ends of the bike use fluid, both ends can collect air and moisture, and both ends deserve attention when the lever or pedal starts to feel vague. This guide walks you through a full fluid refresh and air purge at home, using hand tools and a little patience.

Understanding the Monkey's Brake Layout

On the 2019 Monkey ABS, the front brake lever operates the front caliper and the rear brake pedal operates the rear caliper — the system is not linked, so each end is bled independently. The ABS modulator sits inline in the hydraulic circuit. For routine maintenance, that does not change your approach: you still bleed at the caliper bleeder valves, pushing fresh fluid down from the master cylinder reservoirs and out through the calipers. What ABS does change is the consequence of a mistake. If the reservoir runs dry and air is drawn into the modulator, or if the ABS unit or its lines have been disconnected, the air can be trapped somewhere a hand bleed will not reach. That situation calls for a dealer or a shop with the appropriate diagnostic equipment.

When a Bleed Is Actually Due

Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. As water content rises, the fluid's boiling point drops, and hard, repeated braking can generate enough heat to boil it — producing vapor, a soft lever, and a very long stop. That is why many riders refresh fluid on a schedule even when nothing feels wrong. On top of the calendar, watch for a lever that pulls closer to the grip than it used to, a pedal with a spongy or inconsistent feel, fluid in the reservoir that looks dark or cloudy rather than clear, and any recent work that opened the system: new lines, caliper service, or master cylinder repairs.

Tools and Supplies to Have on the Bench

  • Fresh brake fluid of the type printed on the master cylinder reservoir cap, from a sealed container — opened fluid absorbs moisture, so do not use a bottle that has been sitting around
  • A box-end wrench that fits the bleeder valve snugly
  • Clear tubing that slips tightly over the bleeder nipple
  • A small catch bottle for the old fluid
  • Rags or shop towels, plus a syringe or turkey baster for pulling old fluid out of the reservoir
  • The correct driver for the reservoir cap screws
  • Optional: a one-way check-valve bleeder or a vacuum bleeder, both of which make a solo job easier

Setting Up a Safe, Clean Workspace

Get the Monkey upright and stable on a stand so it cannot tip while you are working the lever. Turn the handlebar until the front reservoir sits level, since a tilted reservoir will spill as soon as the cap comes off. Brake fluid attacks paint and many plastics on contact, so drape rags over the tank area, the instrument cluster, and any bodywork below the reservoirs. If a drop does land on a painted surface, wipe it immediately and rinse the area with water rather than rubbing it in.

Bleeding the Front Brake, Step by Step

  1. Remove the reservoir cap and diaphragm, then use the syringe or baster to draw most of the old fluid out. Leave a little in the bottom so you do not push air into the master cylinder.
  2. Top the reservoir up with fresh fluid from the sealed container.
  3. Push the clear tubing onto the front bleeder valve and route the other end into the catch bottle, with the bottle positioned so the tube's end stays submerged.
  4. Squeeze the front lever smoothly and hold it against the grip.
  5. Open the bleeder about a quarter turn. Fluid and any trapped air will push out through the tube. Watch the tube, not the reservoir, while the bleeder is open.
  6. Close the bleeder before you release the lever. Releasing with the valve open pulls air back into the caliper.
  7. Release the lever, then check the reservoir and top it off. Repeat the squeeze–open–close–release cycle until the fluid coming through the tube runs clean and free of bubbles.
  8. Keep the reservoir at least half full throughout. If it ever runs dry, you have just introduced air upstream and will need to start over.

Bleeding the Rear Brake

  1. Confirm the rear reservoir is level and top it off with fresh fluid.
  2. Fit the tubing over the rear bleeder valve and into the catch bottle.
  3. Press and hold the brake pedal down.
  4. Open the bleeder a quarter turn to release fluid and air, then close it fully before letting the pedal return.
  5. Repeat, topping off the reservoir between cycles, until the fluid runs clear and bubble-free.

If your bike has more than one caliper on an axle, work through them one at a time rather than trying to bleed both at once. As a general habit, start with the caliper farthest from its master cylinder and finish with the closest.

Finishing the Job Correctly

Once clean fluid is flowing at both ends, close each bleeder snugly — firm enough to seal, without cranking on it hard enough to damage the seat. Fill each reservoir to the level marking on the body, reinstall the diaphragm and cap, and wipe down every surface you touched. Then inspect the bleeder valves and the banjo fittings at the master cylinders and calipers for weeping or dampness. A leak here will undo the whole job.

Testing Before You Ride

With the bike still on the stand, squeeze the front lever and press the rear pedal. Both should feel firm and consistent, and neither should slowly sink while you hold steady pressure. Spin each wheel by hand to confirm the brakes are not dragging. Then, in a safe open area at low speed, apply each brake individually and confirm it bites predictably before you ride normally.

When to Hand It to a Shop

If the lever will not firm up after several full bleeding cycles, if it only firms after repeated pumping, if bubbles keep appearing no matter how long you bleed, or if you see fluid at the master cylinder or caliper, stop and have the bike inspected. The same applies if the reservoir ran dry, if the ABS unit or its lines were disturbed, or if you simply are not confident the modulator is free of air — on an ABS-equipped Monkey, that last scenario is a shop job, not a garage one.

Related Shopping Categories

Shop Brake Fluid for a 2019 Honda Monkey ABS Motorcycle.

Shop Brake Lines for a 2019 Honda Monkey ABS Motorcycle.

Shop Brake Pads for a 2019 Honda Monkey ABS Motorcycle.

Shop Stands for a 2019 Honda Monkey ABS Motorcycle.

Shop Brake Tools for a 2019 Honda Monkey ABS Motorcycle.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.