Bleeding the Brakes on a 2014 Honda Grom

Shop parts for a 2014 Honda Grom Motorcycle.

How the Grom's Brakes Are Set Up

The 2014 Grom stops with hydraulic disc brakes at both ends. The front lever drives a master cylinder mounted at the handlebar, and the rear pedal drives a separate master cylinder down at the frame, each feeding its own caliper. Neither circuit is linked to the other, and this model year does not use an anti-lock brake unit, so there is no pump or modulator in the plumbing to complicate the job. That is genuinely good news for a home mechanic: two independent circuits, each bled on its own, with no required sequence between them.

The one thing that makes the Grom a little less forgiving than a full-size bike is reservoir volume. Both master cylinders hold a small amount of fluid, so the level drops quickly as you work. If you pump the lever or pedal without glancing at the reservoir, you will pull air into the system and turn a twenty-minute job into an afternoon of chasing bubbles. Keep your eyes on the fluid level at every step.

When a Bleed Is Actually Needed

Brakes talk to you before they fail. A lever that feels soft or spongy, a lever that now comes noticeably closer to the grip than it used to, or a pedal with a vague, springy feel all point to air somewhere in the circuit. Pop the reservoir cap and look at the fluid: fresh brake fluid is clear and pale, while fluid that has been in service for a couple of seasons turns dark, cloudy, or tea-colored.

Any job that opened the hydraulic system also demands a bleed afterward — new brake lines, a caliper rebuild, a master cylinder service, or a line that was disconnected for any reason. Beyond symptoms, brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. That moisture lowers the fluid's boiling point, and boiled fluid creates gas bubbles that make the lever go soft exactly when you are asking the most of the brakes. Many riders simply refresh the fluid on a regular interval as preventive maintenance rather than waiting for a problem to show up.

Tools and Supplies to Collect First

  • Fresh brake fluid of the type printed on the master cylinder reservoir cap, from a sealed container that has not been sitting open
  • A box-end wrench that fits the bleeder valve snugly — a box-end grips better than an open-end and is less likely to round the hex
  • A length of clear tubing that fits tightly over the bleeder nipple
  • A small catch bottle for the old fluid
  • Rags or shop towels, plus a spray bottle of water
  • A syringe or turkey baster for pulling old fluid out of the reservoir
  • The correct driver for the reservoir cap screws

A one-way check-valve bleeder or a vacuum bleeder is not required, but either one makes the job much easier to do solo, since you no longer need to coordinate the lever and the bleeder valve at the same time.

Setting Up Before You Open Anything

Get the Grom upright and stable on a stand so it cannot tip while you are leaning on the lever. For the front circuit, turn the handlebars until the reservoir sits level — a tilted reservoir will spill fluid the moment the cap comes off. Drape rags over the tank area, the plastics, the instrument cluster, and anything else below the reservoir, because brake fluid attacks paint and plastic on contact. If a drop does land on a painted surface, wipe it up immediately and rinse the area with water rather than waiting until you finish.

Bleeding the Front Brake

  1. Remove the reservoir cap screws, lift off the cap, and set the diaphragm aside on a clean rag.
  2. Draw most of the old fluid out of the reservoir with the syringe, but leave a shallow layer at the bottom so you do not introduce air through the master cylinder port.
  3. Top the reservoir with fresh fluid from the sealed container.
  4. Push the clear tubing onto the bleeder valve and route the other end into the catch bottle, with the bottle positioned so the tubing runs upward before it drops — that keeps an air pocket from running back down.
  5. Fit the box-end wrench onto the bleeder.
  6. Squeeze the front lever slowly and hold it against the grip.
  7. Open the bleeder about a quarter turn. Fluid and any trapped air will push out through the tubing. Watch the tube, not the lever.
  8. Close the bleeder before you release the lever. Releasing with the valve open draws air back in through the bleeder threads.
  9. Release the lever, then check the reservoir and top it off. Repeat the squeeze, open, close, release cycle, topping off every few pumps.
  10. Keep going until the fluid coming through the tubing is clean and free of bubbles, then finish with the bleeder closed and the lever held.

If your bike is fitted with more than one front caliper, bleed each caliper separately, starting with the one farthest from the master cylinder in terms of hydraulic path.

Bleeding the Rear Brake

  1. Check that the rear reservoir sits level with the bike upright, then open it and pull out most of the old fluid.
  2. Refill with fresh fluid and set the diaphragm aside where it stays clean.
  3. Attach the tubing and catch bottle to the rear caliper bleeder and fit the wrench.
  4. Press the pedal down and hold it.
  5. Crack the bleeder a quarter turn, let the fluid and air escape, then close it fully before letting the pedal return.
  6. Top off the reservoir and repeat until the fluid runs clean and bubble-free.

The rear circuit on the Grom holds very little fluid, so expect to refill the reservoir more often than you would on a larger bike.

Finishing the Job

With the lever and pedal released, snug the bleeder valve down firmly — tight enough that it will not weep, but not so tight that you crush the seat or round the hex. Fill the reservoir to the level marking on the body, reinstall the diaphragm so it sits flat, and refit the cap. Wipe down the caliper, the bleeder, and the master cylinder, then look closely at the bleeder and at the banjo fittings on the lines for any sign of weeping. A dry paper towel pressed against each joint will show a leak you might miss by eye.

Testing Before You Ride

Pull the front lever and press the rear pedal. Both should feel firm and consistent, and neither should creep slowly toward the grip or the floor while you hold steady pressure. Spin each wheel by hand to confirm the brakes are not dragging. Then, in a safe open area, test the brakes at low speed before riding normally. If anything feels soft at that point, stop and bleed again rather than hoping it settles in.

When to Hand It Off to a Shop

If the lever will not firm up after several honest bleeding attempts, if it only firms up after repeated pumping, or if bubbles keep appearing no matter how long you work, something else is wrong — a failing master cylinder seal, a pinhole in a line, or a caliper that is drawing air. Fluid weeping from the master cylinder or caliper is the same signal. On a bike with an anti-lock unit, air that has entered the pump itself usually needs a dealer-level procedure to clear, so if the reservoir ever ran dry or a line was disconnected at the modulator, let a shop handle it. Brakes are not the system to gamble on.

Related Shopping Categories

Shop Brake Fluid for a 2014 Honda Grom Motorcycle.

Shop Brake Lines for a 2014 Honda Grom Motorcycle.

Shop Brake Pads for a 2014 Honda Grom Motorcycle.

Shop Stands for a 2014 Honda Grom Motorcycle.

Shop Brake Tools for a 2014 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.