How To Bleed 2024 Honda Grom ABS Motorcycle Brakes

Bleeding the Brakes on a 2024 Honda Grom ABS

What the 2024 Grom ABS Brake Layout Means for Bleeding

The 2024 Honda Grom ABS uses hydraulic disc brakes at both ends, and the ABS designation confirms that an anti-lock braking system is part of the package. For a routine fluid refresh or air removal, you are working with two separate hydraulic circuits: a front system operated by the hand lever and a rear system operated by the foot pedal. Each circuit has its own reservoir and caliper bleeder, so each must be bled on its own. The ABS hardware does not change the basic caliper-bleeding steps for normal maintenance, but it does add an important boundary. If the reservoir has run dry, if the ABS unit or its lines have been disconnected, or if you suspect air has moved into the ABS unit itself, a simple bleed at the calipers may not be enough. That kind of air usually needs dealer-level equipment or a diagnostic procedure, so it is the point to stop and let a shop handle the job. This Grom uses a single front caliper, so there is one front bleed point; the rear brake is bled at its own caliper.

When These Brakes Need Bleeding

A soft or spongy lever is the classic sign that air is in the front circuit, and a rear pedal that feels vague or travels farther than it used to points to the same problem at the rear. A lever that pulls closer to the grip than it once did, or a pedal that slowly sinks while you hold steady pressure, also means the system needs attention. Dark, cloudy, or contaminated fluid in either reservoir is another reason to bleed. So is any recent work that opened the hydraulic system, such as new brake lines, caliper service, or master cylinder work.

Even when the brakes feel normal, brake fluid absorbs moisture over time. That moisture lowers the fluid’s boiling point, which can lead to brake fade under hard or repeated use. Many riders refresh the fluid on a regular schedule for that reason alone. On a small street bike like the Grom ABS, firm and predictable brakes matter, so do not wait for a lever to feel bad before inspecting the fluid.

Tools and Supplies to Gather

• Fresh brake fluid of the type marked on the master cylinder reservoir cap, from a sealed container
• A box-end wrench that fits the bleeder valve snugly
• Clear tubing that fits tightly over the bleeder valve
• A small catch bottle for the old fluid
• Rags or shop towels, plus water for rinsing spills
• A syringe or turkey baster for removing old fluid from the reservoir
• The correct screwdriver or driver for the reservoir cap screws

A one-way check-valve bleeder or a vacuum bleeder can make the job easier when you are working alone, but the manual lever-and-bleeder method works fine if you take your time. Keep the catch bottle below the caliper so gravity helps, and make sure the clear tubing is long enough to route away from painted parts.

Preparation Before You Open the Reservoir

Support the Grom securely upright on a stand so it cannot tip while you are pressing the lever or pedal. Turn the handlebars so the front reservoir sits level before you remove the cap; a level reservoir keeps fluid from spilling out as soon as the cover comes off. Cover the painted surfaces, plastic panels, and the instrument area with rags. Most brake fluid damages paint and plastic on contact, so treat every drip as urgent. If a spill happens, wipe it up immediately and rinse the area with water.

Work in a well-ventilated area and keep the fluid container capped when you are not pouring. Do not shake the fresh fluid bottle; you do not want to introduce bubbles before the fluid even reaches the reservoir.

Bleeding the Front and Rear Circuits

1. Set up at the front reservoir first. Remove the cap and diaphragm, then use the syringe or baster to pull most of the old fluid out of the reservoir. Do not let the reservoir run dry at any point.
2. Refill the reservoir with fresh fluid of the type marked on the cap, leaving room for the diaphragm and cap to go back on later.
3. Push the clear tubing onto the front caliper bleeder and route the other end into the catch bottle. Make sure the tubing fits snugly so air cannot be drawn in around it.
4. Fit the box-end wrench onto the bleeder. Squeeze the front lever and hold it firm against the grip.
5. Open the bleeder about a quarter turn. Fluid and any trapped air will move down the tube. Close the bleeder before you release the lever. Releasing the lever with the bleeder open can pull air back into the caliper.
6. Repeat the squeeze, hold, open, close, and release sequence. Check the reservoir often and top it off so it never gets low enough to draw air into the master cylinder.
7. Continue until the fluid coming through the clear tube is clean, fresh-looking, and free of bubbles. Then close the bleeder snugly without overtightening it.
8. Move to the rear circuit and repeat the same process using the rear reservoir and the foot pedal. Press and hold the pedal, open the rear bleeder, close it before releasing the pedal, and keep the rear reservoir topped off.
9. On any bike with two front calipers, you would bleed each front caliper in turn, generally starting with the caliper farthest from the master cylinder. This Grom has a single front caliper, so you only need to service that one front bleed point.

Finishing and Leak Checks

When both circuits are bled, top each reservoir to the correct level marking. Reinstall the diaphragm and cap carefully so the rubber seal sits flat and does not pinch. Wipe away any fluid around the reservoir, bleeder valves, and banjo fittings, then rinse any painted or plastic area that may have been touched. Check for leaks at the bleeder valves and at the banjo fittings by holding pressure on the lever and pedal and watching for weeping or wetness. A bleeder that is snug but not overtightened should stay dry; if it seeps, stop and correct it before riding.

Testing Before You Ride

The front lever and rear pedal should feel firm and consistent, not spongy, and they should not slowly sink while you hold steady pressure. Spin each wheel by hand to confirm the brakes are not dragging. With the bike upright and the area clear, test the brakes at low speed before riding normally. If anything feels different from before the bleed, do not ride the bike until you find out why.

Troubleshooting and When to See a Shop

If the lever will not firm up after several bleeding attempts, if it firms only after pumping, or if bubbles keep appearing no matter how long you bleed, stop and reassess. Persistent air often means the reservoir ran low, a fitting is drawing air, or fluid is escaping somewhere. Fluid leaking from the master cylinder or caliper is another reason to stop. Because this is a 2024 Grom ABS, any suspicion that air entered the ABS unit — especially after a dry reservoir or disconnected lines — should send the bike to a shop rather than into a longer home bleed session. A firm, clean, leak-free system is the only acceptable result before you ride.

Related Shopping Categories

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Shop Brake Tools for a 2024 Honda Grom 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.