Bleeding the Front Brake on Your 1990 Kawasaki EX500A
Shop parts for a 1990 Kawasaki EX500A Motorcycle.
Know Your Bike's Brake Layout First
The 1990 Kawasaki EX500A stops on a single hydraulic disc up front, fed by a handlebar-mounted master cylinder and worked by the right-hand lever. Out back, the EX500A uses a mechanical drum brake driven by cable and rod linkage. There is no fluid, no bleeder valve, and no hydraulic circuit at the rear wheel, so nothing there needs bleeding — it is adjusted, not bled. Everything in this article applies to the front system only: one reservoir, one caliper, one bleeder. If your bike has been modified with a second front caliper, treat each caliper as its own job and bleed them one at a time.
When Bleeding Is Worth Your Time
Brake fluid is hygroscopic, meaning it pulls moisture out of the air over the months and years. 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 at exactly the wrong moment, and it corrodes the internals of the master cylinder and caliper. That is why many riders refresh the fluid on a schedule even when the brake feels fine.
Bleed right away if the lever feels spongy, if it now comes noticeably closer to the grip than it used to, if the fluid in the reservoir looks dark or cloudy, or if you have just opened the hydraulic system — new brake line, caliper rebuild, master cylinder work, or a reservoir that ran dry. Any of those events lets air in, and air compresses where fluid does not.
Tools and Supplies to Gather
- Fresh brake fluid of the type printed on the master cylinder reservoir cap, from a sealed container.
- 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 or jar 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 makes this a much easier one-person job, but the manual method below works fine with patience.
Setting Up Before You Open Anything
Get the bike upright and stable on a stand so the front end is not going to shift while you are leaning on the lever. Turn the handlebars until the front reservoir sits level — on the EX500A that usually means turning them slightly to the left — because an unlevel reservoir spills fluid the moment you crack the cap.
Then cover everything. Brake fluid eats paint, clear coat, plastic, and instrument lenses on contact. Drape rags over the tank, the fairing or headlight area, the gauges, and the front fender. If a drop does land on a painted surface, wipe it up immediately and rinse the area with water rather than waiting until you are done.
The Bleeding Procedure, Step by Step
- 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 at the bottom that you are not pulling air into the master cylinder port.
- Refill the reservoir with fresh fluid from the sealed container, up near the full mark.
- Push the clear tubing onto the bleeder valve on the front caliper and route the other end into the catch bottle, with the bottle sitting lower than the caliper and the tube forming a gentle loop.
- Squeeze the front lever slowly and hold it against the grip. Slow, full strokes move fluid without aerating it.
- With the lever held, open the bleeder about a quarter turn with the box-end wrench. Fluid and air will push out through the tube. Watch the tube, not the reservoir.
- Close the bleeder snugly before you release the lever. Releasing with the bleeder open sucks air straight back into the caliper, which is the single most common way this job goes wrong.
- Release the lever, 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 draw air into the master cylinder.
- Continue until the fluid coming through the tube is clean and bright and you see no bubbles at all, even on a slow, deliberate stroke.
If your bike has two front calipers, bleed the one farthest from the master cylinder first, then the closer one, using the same sequence for each.
Finishing Up and Checking for Leaks
Close the bleeder snugly — firm, not gorilla-tight, since overtightening can damage the seat. Pull the tube off and wipe the caliper clean. Fill the reservoir to the level marking, reinstall the diaphragm and cap, and wipe down any fluid that escaped. Then look closely at the bleeder and at the banjo fitting where the line meets the caliper and master cylinder for any weeping or wetness. A dry paper towel pressed against each joint tells you quickly whether anything is seeping.
Testing Before You Ride
Squeeze the lever hard and hold it. It should feel firm and consistent, and it should not slowly creep toward the grip under steady pressure — a lever that sinks means fluid is bypassing somewhere or air is still in the system. Spin the front wheel and confirm it turns freely with no drag and no rubbing sound. Then, in a safe, empty area at low speed, apply the brake gently and then firmly before you ride normally. Check the rear drum's adjustment at the same time, since it is doing its share of the stopping.
When to Stop and Take It to a Shop
If the lever will not firm up after several full rounds of bleeding, if it only feels good right after you pump it, if bubbles keep appearing no matter how long you go, or if you find fluid weeping from the master cylinder or caliper, stop and have the system inspected. Those symptoms point to a failing master cylinder seal, a damaged line, or a caliper issue that bleeding will not fix. Hand the job to a professional as well if the reservoir ran completely dry and you cannot get a firm lever back, or if you are simply not confident in what you are feeling through the lever — brakes are not the place to guess.
Related Shopping Categories
Shop Brake Fluid for a 1990 Kawasaki EX500A Motorcycle.
Shop Brake Lines for a 1990 Kawasaki EX500A Motorcycle.
Shop Brake Pads for a 1990 Kawasaki EX500A Motorcycle.
Shop Stands for a 1990 Kawasaki EX500A Motorcycle.
Shop Brake Tools for a 1990 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.
