How to Bleed and Replace Brake Fluid on a 2017 Kymco MXU 270

Shop parts for a 2017 Kymco MXU 270 ATV.

This MotoSport service guide explains a safe, effective method to flush and replace the brake fluid on a 2017 Kymco MXU 270. Follow these steps carefully to maintain braking performance and prevent contamination or damage to brake components.

What you need

  • Manufacturer-specified brake fluid (check the reservoir cap for DOT rating; DOT3 or DOT4 are common)
  • Clear tubing and a catch bottle
  • Brake bleeding wrench or appropriately sized open-end wrench
  • Hand vacuum pump with bleed adapter or a bench/pressure bleeder (vacuum pump recommended for one-person jobs)
  • Large syringe or fluid-transfer pump
  • Clean rags, gloves, and eye protection
  • Brake cleaner and fine brush or cloth for cleaning around fittings
  • Jack or ramps and stands to access wheels safely

Safety first

  • Work on a level surface with the ignition off and key removed.
  • Avoid skin and paint contact with brake fluid — it damages paint and irritates skin. Rinse spills immediately.
  • Never reuse old fluid. Dispose of used fluid according to local hazardous-waste rules.

Model notes for the 2017 Kymco MXU 270

  • The MXU 270 uses a simple hydraulic braking system without advanced ABS electronics, which makes standard manual bleeding straightforward.
  • Reservoirs on ATVs can be small; keep the master cylinder reservoir topped during bleeding to avoid introducing air.
  • Terrain and heavy-duty trail use accelerate fluid contamination. MotoSport recommends inspecting brake fluid annually and replacing every 12 to 24 months depending on use and moisture exposure.
  • Caliper mounting hardware and banjo bolts on Kymco models can seize from corrosion. Clean and apply proper anti-seize where specified; if bolts are tight, apply penetrating oil and allow time before loosening.

Preparation

  1. Park the ATV, set the parking brake, and secure on stands so wheels are free if needed.
  2. Clean around the master cylinder reservoir cap to prevent dirt entering the system.
  3. Remove the cap and the diaphragm/cover. Note any rubber filter element orientation so you can reinstall correctly.
  4. Use a syringe to remove most old fluid from the reservoir so you can add fresh fluid without overfilling during the flush.

Bleeding sequence

MotoSport recommends starting with the caliper furthest from the master cylinder and finishing with the nearest. For most MXU layouts that means:

  • Right rear (farthest)
  • Left rear
  • Right front
  • Left front (nearest)

Bleeding procedure – vacuum or syringe method

  1. Top off the reservoir with fresh fluid. Keep the cap loose on the reservoir to avoid pressure build-up.
  2. Fit clear tubing onto the caliper bleed nipple and place the other end into your catch bottle partially filled with fresh fluid to avoid drawing air back in.
  3. Crack the bleed nipple about a quarter turn with your wrench.
  4. Attach your vacuum pump to the tubing and draw fluid while a helper slowly squeezes the brake lever/pedal. If you are single-handed, use a small lever pump or repeat squeeze-and-hold with the vacuum.
  5. Continue until the fluid runs clear with no air bubbles. While bleeding, keep the reservoir topped to prevent air ingestion.
  6. Tighten the bleed nipple while the lever is held firm (for two-person method) or immediately after stopping vacuum draw (for vacuum method). Confirm no leaks.
  7. Wipe the caliper and nipple clean, then move to the next caliper following the same steps.

Alternative — two-person squeeze method

  1. One person sits on the ATV and pumps the brake lever several times, then holds it against firm pressure.
  2. The second person opens the bleed nipple to let fluid/air out, then closes it before the lever is released. Repeat until clear fluid appears and no bubbles are present.
  3. Always close the bleed nipple before the lever is released to avoid drawing air back in.

Finishing

  • Top the reservoir to the proper level, reinstall the diaphragm and cap, and clean any spilled fluid.
  • Test brake lever/pedal firmness with the ATV still supported. If the lever feels spongy, repeat bleeding until solid feel and no air is present.
  • Lower the ATV and perform a slow, controlled road or trail test to confirm braking performance before normal use.

Tips & common issues

  • Never mix different DOT ratings unless permitted by the master cylinder cap; when in doubt, purge and use fresh fluid of the correct DOT rating.
  • If caliper pistons do not move freely or return slowly, remove calipers for inspection and rebuild or replace seals as needed.
  • Stuck or rounded bleed nipples may require extraction and replacement; keep a spare set on hand if you service brakes frequently.
  • Corrosion on banjo bolts or copper washers can cause leaks; replace crush washers whenever you open the hydraulic line.

MotoSport recommends performing this service in a clean area and keeping a log of brake-fluid changes as part of your MXU 270 maintenance record.

Related Shopping Categories

Shop Brake Fluid for a 2017 Kymco MXU 270 ATV.

Shop Brake Bleeders for a 2017 Kymco MXU 270 ATV.

Shop Brake Pads for a 2017 Kymco MXU 270 ATV.

Shop Brake Lines for a 2017 Kymco MXU 270 ATV.

Shop Brake Tools for a 2017 Kymco MXU 270 ATV.

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.