Bleeding the Brakes on a 1989 Kawasaki EX500A
Shop parts for a 1989 Kawasaki EX500A Motorcycle.
Start by Understanding the EX500A's Brake Layout
The 1989 EX500A uses hydraulic disc brakes at both ends. A hand lever on the right bar pressurizes the front caliper, and a foot pedal on the right side works the rear caliper through its own master cylinder and line. Two separate circuits, one shared service routine — so this job walks you through the front and then the rear. This machine predates anti-lock and linked braking completely, which is good news in the garage: there is no ABS pump to trap air and no combined-brake sequence to respect. What you have is a master cylinder, a hose, and a caliper at each end, and the entire goal is to push fresh fluid through until nothing but clean, bubble-free fluid comes out.
If your bike has been modified with a second front caliper, treat each caliper as its own bleed point and work through them one at a time rather than trying to do both at once.
Why and When to Bleed the EX500A's Brakes
Brake fluid is hygroscopic, meaning it pulls moisture out of the air over time, even through sealed rubber components. Moisture does two bad things: it lowers the fluid's boiling point, so hard repeated braking can boil the fluid and give you a lever that goes soft or long exactly when you need it most, and it corrodes the internals of the master cylinder and caliper. On a bike this age, the fluid has often gone years without attention.
Bleed the system if the lever or pedal feels spongy, if the lever now travels closer to the grip than it used to, if the fluid in the reservoir looks dark, cloudy, or gritty, or if you have just replaced a line, serviced a caliper, or had the master cylinder apart. Many riders also simply refresh the fluid on a regular interval as preventive maintenance, and on a 1989 machine that habit is worth keeping.
Tools and Supplies to Have Ready
- Fresh brake fluid of the type printed on the master cylinder reservoir cap, from a sealed container — once a container is opened, it starts absorbing moisture, so use new stock
- A box-end wrench that fits the bleeder valve snugly
- 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 means of rinsing spills
- 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 makes the job much easier when you are working alone, since you no longer need a helper to work the lever while you open and close the valve.
Setting Up Before You Open Anything
Get the bike held securely upright on a stand so it cannot tip while you are leaning on the lever. For the front circuit, turn the handlebars until the reservoir on the bar sits level — a tilted reservoir will spill. Drape rags over the tank or bodywork, the instrument cluster, and anything painted or plastic below the reservoir, because brake fluid attacks paint and clear plastic on contact. If a drop lands where it shouldn't, wipe it up immediately and rinse the area with water rather than waiting until you finish.
The Bleeding Procedure, Step by Step
- Wipe the reservoir cap and surrounding area clean so grit cannot fall in, then remove the cap and the rubber diaphragm.
- Use the syringe or baster to draw most of the old fluid out of the reservoir. Do not pump the lever with the reservoir empty, and do not let the level drop far enough to uncover the port at the bottom.
- Refill with fresh fluid to a sensible working level, leaving room to top off as you go.
- Push the clear tubing onto the bleeder nipple and route the other end into the catch bottle, with the bottle positioned so the tube's end stays submerged.
- Squeeze the lever and hold it firm. For the rear, press and hold the pedal.
- Open the bleeder about a quarter turn. Fluid and any trapped air will push out through the tube. You will feel the lever or pedal travel toward the end of its stroke.
- 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. Check the reservoir level every few cycles and top it off. Never let it run dry, or you will pump air into the line and start over.
- Keep going until the fluid coming through the tube is clean and free of bubbles, and the lever or pedal feels firm rather than spongy.
- Move to the other circuit and repeat the whole sequence with its own reservoir, bleeder, and lever or pedal.
As a general practice, start with the caliper farthest from its master cylinder and finish with the closest, and if there are two front calipers, bleed one completely before starting the second.
Finishing Up and Checking for Leaks
Close the bleeder snugly with the box-end wrench — firm enough that it will not weep, but never so tight that you crush the seat or strip the caliper threads. Pull the tubing off and wipe the nipple clean. Fill the reservoir to the level marking, work the diaphragm back into place, and refit the cap. Clean up any fluid residue around the reservoir, bleeder, and banjo fittings, then look closely for weeping at the bleeder and at the hose fittings after you have worked the lever a few times.
Testing Before You Ride
Hold steady pressure on the lever and on the pedal. Each should feel firm and consistent, and neither should slowly sink toward the end of its travel while you hold it. Spin each wheel by hand to confirm the brake is not dragging. Then, in a safe open area at low speed, apply the front and rear brakes separately and together before riding normally.
When to Stop and Take It to a Shop
If the lever will not firm up after several honest attempts, if it only firms up when you pump it, if bubbles keep appearing no matter how long you bleed, or if you find fluid weeping from the master cylinder or caliper, stop and have the system inspected. A lever that never comes back to a solid feel usually means air is entering somewhere you cannot see, and that is a job for someone with the right parts and experience.
Related Shopping Categories
Shop Brake Fluid for a 1989 Kawasaki EX500A Motorcycle.
Shop Brake Lines for a 1989 Kawasaki EX500A Motorcycle.
Shop Brake Pads for a 1989 Kawasaki EX500A Motorcycle.
Shop Stands for a 1989 Kawasaki EX500A Motorcycle.
Shop Brake Tools for a 1989 Kawasaki EX500A 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.
