Bleeding the Brakes on a 2023 Honda Grom: A Step-by-Step Guide
Shop parts for a 2023 Honda Grom Motorcycle.
The 2023 Honda Grom uses hydraulic disc brakes at both ends, so both the front lever and the rear pedal push fluid through a sealed system to squeeze the calipers. That is good news for stopping power, and it also means both circuits need periodic attention. Honda offers the Grom in a standard version and an ABS version, so check your own bike before you start — if the front fender or the area near the caliper carries an ABS sensor ring and a wheel-speed sensor, you have the ABS model, and that changes a couple of the cautions below. Everything else about the job is the same on either version.
When a Grom Needs Its Brakes Bled
Air is the enemy here. Any air bubble trapped in the line compresses under pressure instead of moving fluid, and the result is a lever or pedal that feels soft, vague, or that travels closer to the grip or the footpeg than it used to. If your front lever can be pulled nearly to the bar, or the rear pedal sinks under steady pressure, you have air somewhere.
Fluid condition matters just as much. Brake fluid is hygroscopic, meaning it pulls moisture out of the air over time. Moisture lowers the fluid's boiling point, and on a long descent or a hard stop the fluid can boil and create gas inside the system — brake fade, right when you need the brakes most. Dark, cloudy, or discolored fluid in the reservoir is a clear signal to flush. Many riders simply refresh the fluid on a regular interval as preventive maintenance, and you should always bleed after any work that opened the hydraulic system: new lines, a caliper rebuild, or master cylinder service.
What to Gather Before You Start
- Fresh brake fluid of the type printed on your Grom's master cylinder reservoir cap, poured from a sealed container. Do not substitute a different type, and do not use a bottle that has been open and sitting on a shelf.
- A box-end wrench that fits the bleeder valve snugly. A box-end grips all the flats and is far less likely to round the bleeder than an open-end wrench.
- A length of clear tubing that fits tightly over the bleeder nipple, plus a small catch bottle to hang it in.
- Rags or shop towels, and a syringe or turkey baster for pulling old fluid out of the reservoir.
- The correct driver for the reservoir cap screws.
- Optional but helpful: a one-way check-valve bleeder or a vacuum bleeder, either of which makes a solo job much easier.
Setting Up Safely
Get the Grom upright and stable on a stand so it cannot tip while you are working the lever. For the front circuit, turn the handlebar until the reservoir on the master cylinder sits level — a tilted reservoir will spill the moment you open the cap. Drape rags over the tank area, the plastics, the instrument cluster, and anything painted below the reservoir. Brake fluid attacks paint and many plastics on contact, so treat every drip as urgent: wipe it immediately and rinse the area with water.
Work through one circuit at a time. Start with the front, finish it completely, then move to the rear.
The Bleeding Procedure
- Remove the reservoir cap and diaphragm. Use the syringe or baster to draw most of the old fluid out of the reservoir, but stop before the bottom — never let the reservoir run dry, or you will pump air straight into the line.
- Top the reservoir up with fresh fluid from your sealed container.
- Push the clear tubing onto the bleeder valve and route the other end into the catch bottle, with the bottle positioned so the tube's end stays submerged.
- Squeeze the front lever and hold it firm. For the rear, press and hold the pedal.
- With the lever or pedal held, 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.
- Close the bleeder before you release the lever or pedal. Releasing first draws air back in through the open valve — this is the single most common mistake in the whole job.
- Release, then repeat: squeeze, hold, open, close, release. Keep an eye on the reservoir and top it off every few cycles so it never drops low enough to suck air.
- Continue until the fluid coming through the tube is clean, bright, and free of bubbles, and the lever or pedal feels firm.
- Move to the rear caliper and repeat the same sequence with the pedal. If your bike has more than one caliper on a circuit, bleed them one at a time, starting with the caliper farthest from the master cylinder and working toward the closest.
Finishing the Job
Close the bleeder snugly — firm and sealed, but not cranked down with force, since overtightening can damage the seat. Pull the tubing off and wipe the valve clean. Fill the reservoir to the level marking on the body, reinstall the diaphragm and cap, and wipe away any fluid that found its way onto the bike. Then look closely at the bleeder valves and the banjo fittings at the master cylinder and caliper for weeping or wetness. A dry fitting after a few firm lever pulls is what you want to see.
Testing Before You Ride
With the bike still on the stand, spin each wheel by hand and confirm the brakes are not dragging. Then check feel: the lever and pedal should be firm and consistent, and should hold pressure without slowly sinking. If the lever firms up only after several pumps, there is still air in the system. Take the Grom to an empty lot and test at low speed first, gradually building up, before riding normally.
Troubleshooting and When to Stop
If the lever will not firm up after several full bleeding cycles, if bubbles keep appearing no matter how long you work, or if you find fluid leaking at the master cylinder or a caliper, stop and diagnose rather than continuing to pump fluid through. On the ABS version of the 2023 Grom, a normal bleed at the caliper valves is fine for routine fluid refreshment. But if the reservoir ever ran dry, or if the ABS unit or its lines were disconnected, air may have entered the ABS modulator itself — that typically needs a dealer-level procedure or diagnostic tool, and the bike should go to a shop. The same advice applies if you are simply not confident in what you are seeing. Brakes are not the place to guess, and a professional bleed costs far less than a failed stop.
Related Shopping Categories
Shop Brake Fluid for a 2023 Honda Grom Motorcycle.
Shop Brake Lines for a 2023 Honda Grom Motorcycle.
Shop Brake Pads for a 2023 Honda Grom Motorcycle.
Shop Stands for a 2023 Honda Grom Motorcycle.
Shop Brake Tools for a 2023 Honda Grom 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.
