Bleeding the Brakes on Your 2025 Ducati Monster 937 Plus
Shop parts for a 2025 Ducati Monster 937 Plus Motorcycle.
The 2025 Ducati Monster 937 Plus runs a fully hydraulic disc brake setup at both ends, and it is backed by an ABS unit as part of the bike’s standard electronics package. That means both the front lever and the rear pedal push fluid through lines that pass through the ABS modulator before reaching the calipers. For routine maintenance—flushing old fluid and purging air that entered at the caliper or master cylinder—a normal bleed at the caliper bleeders is all that is required. This guide walks you through that job from start to finish, with the caveats that matter for an ABS-equipped Monster.
When a Bleed Is Due
Brake fluid is hygroscopic, meaning it pulls moisture out of the air over time. Even on a sealed system, that moisture lowers the fluid’s boiling point, and a boiling fluid creates vapor that behaves exactly like air in the lines. On a heavy street bike like the Monster 937 Plus, that shows up as a lever that goes soft or long during hard, repeated braking. Many riders simply refresh the fluid on a regular interval rather than waiting for a symptom.
Beyond scheduled maintenance, bleed the brakes any time the lever or pedal feels spongy, the lever creeps closer to the grip than it used to, the fluid in the reservoir looks dark or cloudy, or you have opened the hydraulic system for any reason—new lines, caliper service, or master cylinder work. A lever that firms up only after several quick pumps is a classic sign that air is trapped somewhere in the circuit.
Tools and Supplies to Gather
- Fresh brake fluid of the type printed on the master cylinder reservoir cap, from a sealed container. Do not substitute a different fluid type.
- A box-end wrench that fits the bleeder valve snugly—test the fit before you start.
- Clear tubing sized to fit tightly over the bleeder nipple, plus a 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, which makes a solo job much easier.
Setting Up Safely
Get the Monster 937 Plus supported securely and upright 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—an angled reservoir will spill. Before you open anything, drape rags over the tank, the plastics, the instrument cluster, and any painted surface near the reservoir and calipers. Brake fluid attacks paint and plastic on contact, so wipe up any drip immediately and rinse the area with water if a spill happens.
Work in a well-ventilated space and keep the fluid container capped whenever you are not pouring from it, since fresh fluid starts absorbing moisture the moment it meets air.
Step-by-Step 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 leave enough in the bottom that you do not expose the port and pull air into the master cylinder.
- Top the reservoir up with fresh fluid from the 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 against the grip. For the rear, press and hold the pedal.
- With the lever or pedal held, open the bleeder about a quarter turn with the box-end wrench. Fluid and any trapped air will push out through the tube.
- Close the bleeder before you release the lever or pedal. Releasing with the bleeder open draws air back into the caliper—this is the single most common mistake in the job.
- Release the lever or pedal slowly, then repeat the squeeze-hold-open-close cycle. Watch the tube: you are looking for a steady stream with no bubbles, and a color change from dark old fluid to clean new fluid.
- Check the reservoir level every few cycles and top it off. Never let it run low enough to draw air in at the master cylinder.
- If your bike has two front calipers, bleed each one in turn, finishing the second caliper with a final pass. As a general practice, start with the caliper farthest from the master cylinder in terms of hydraulic path, then move to the closer one.
- Repeat the same sequence at the rear caliper if you are flushing the rear circuit as well.
Finishing the Job
When clean, bubble-free fluid is coming through and the lever feels firm, close the bleeder and tighten it snugly with the box-end wrench—firm, not forced. Overtightening can damage the seat. Fill the reservoir to the level marking on the body, reinstall the diaphragm and cap, and wipe down every surface you touched. Inspect the bleeder and the banjo fittings at the caliper and master cylinder for weeping, and check the reservoir seam for seepage after you have worked the lever a few times.
Testing Before You Ride
With the bike still supported, spin each wheel by hand to confirm the brakes are not dragging. Then, with the bike on the ground, pump the lever and pedal and hold steady pressure for several seconds. Both should feel firm and consistent and should not slowly sink. Take the bike to a quiet, low-speed area and test the brakes gently before riding normally.
Troubleshooting and When to Visit a Shop
If the lever will not firm up after several full bleeding passes, if it only firms after pumping, or if bubbles keep appearing no matter how long you bleed, stop and reassess. Persistent air usually means a fitting is drawing air in, or the master cylinder is bypassing internally. Fluid weeping from the master cylinder or caliper also points to a seal issue that bleeding will not fix.
One ABS-specific caution: if the reservoir ever ran dry, or if the ABS unit or its lines were disconnected, air may have entered the modulator itself. A standard caliper bleed will not necessarily clear that, and the system may need a dealer-level procedure or diagnostic tool to cycle the pump. In that case, or if you are simply not confident in the result, hand the bike to a qualified technician—brakes are not the place to accept a maybe.
Related Shopping Categories
Shop Brake Fluid for a 2025 Ducati Monster 937 Plus Motorcycle.
Shop Brake Lines for a 2025 Ducati Monster 937 Plus Motorcycle.
Shop Brake Pads for a 2025 Ducati Monster 937 Plus Motorcycle.
Shop Stands for a 2025 Ducati Monster 937 Plus Motorcycle.
Shop Brake Tools for a 2025 Ducati Monster 937 Plus 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.
