Notice the locking bleeder hose that allows one person to safely change brake fluid.

One of the regular maintenance items for hydraulic disc brakes is the periodic brake fluid change, which is supposed to be done every two years. When changing the fluid, it is essential to loosen the bleeder plug on the brake caliper to bleed air from the brake hose and inside the caliper, but care must be taken to prevent the hose attached to the plug from coming loose. An effective solution for this task is an air bleeder hose with a lock that can be securely fastened to the plug tip.

Whether or not air is allowed in the path when changing brake fluid

Disc brake fluid is characterized by a high boiling point that does not boil even at the high temperatures generated during braking. On the other hand, the fluid is highly hygroscopic, and even a small percentage of moisture can cause the boiling point to drop by 50°C or more, which can lead to vapour lock (fluid boils and bubbles are generated, causing the brakes to fail), so replacement is necessary. The brake fluid replacement process, which is generally performed every two years, consists of either injecting new fluid into the master cylinder, brake hoses, and calipers with the old fluid remaining in them, or removing and cleaning them before injecting fluid into them. If the fluid is changed regularly, the former method is fine. However, if the fluid has not been changed for a long period of time and has turned brown, it is better to disassemble and clean the master cylinder and calipers, since there is often sludge-like dirt inside the master cylinder and calipers. When injecting new fluid after disassembling and cleaning, the time and effort required to bleed air in the path must be taken into consideration. Whether the fluid is pumped in from the master cylinder side by repeatedly operating the brake lever or pedal, or from the caliper bleeder plug using a syringe, the final air bleeding operation is required to exhaust any air remaining in the master cylinder, caliper, banjo bolts, etc. Of course, air bleeding is also necessary when replacing the old fluid with new fluid from the master cylinder while adding new fluid while the old fluid remains in the route. However, assuming that the old fluid does not have air bites, the risk of air mixing with the new fluid when it is added without interruption is extremely small. From the standpoint of work efficiency, it is better to "add and replace" fluid without draining it before contamination accumulates inside the master cylinder and calipers, even if the fluid visible from the inspection window is clear. However, this does not apply when replacing fluid with replacement of parts due to damage to the master cylinder cup seal or caliper piston seal.

If the fluid & air bleed hose is disconnected from the bleeder plug, it's a big deal.

When replacing brake fluid, whether it is a refill or full replacement, the fluid and air are drained from the caliper's bleeder plug while replacing the fluid. At this time, fluid leakage from the bleeder plug is a source of trouble. The standard method is to insert a silicone hose into the tip of the bleeder plug and tie it off at the base with a cable tie to prevent it from coming loose, but it may come loose by some chance. In the air bleed operation, the fluid mixed with air is drained vigorously by loosening the plug slightly while holding the lever and applying pressure, but if the hose is caught in the force and disconnected, fluid will be sprayed. If the fluid is caught by the force of the pressure, the hose can be dislodged and the fluid can be injected. The fluid that damages the paint must be immediately rinsed out with water, but it can splash into unexpected places, so careful checking is essential if fluid is sprayed. The bleeder plug and hose must be securely connected to prevent this from happening, but problems can occur when "it's not supposed to ......".

A convenient item that locks using the nub at the tip of the plug.

To ensure that the bleeder plug and air bleeder hose are securely plugged in, it is important to select a hose with an inside diameter that matches the plug tip size, and the bleeder hose set sold by tool store Straight features a locking adapter at the plug attachment point. The bleeder hose set sold by tool shop Straight features a locking adapter at the plug attachment point. The lock, which can be opened and closed by pinching it with the fingers, rests on the neck at the end of the bleeder plug, and together with the seal built into the adapter, it keeps the bleeder plug under proper tension and will not come off. A similar rubber adapter that fits over the plug is also available, but this one has a physical lock that prevents it from coming off unexpectedly, which is a big advantage.

With the one-way valve, fluid can be changed without opening and closing the bleeder plug.

In addition, a one-way valve is also incorporated in the middle of this hose. Fluid that passes through the one-way valve does not return to the bleeder plug side, so there is no need to open and close the bleeder plug in response to brake lever or pedal operation. Generally, assistance is required to bleed air from the front brake left caliper, but with the one-way valve, a one-person operation is possible, and the brake fluid in the automobile can be changed by one person. While there is an advantage in being able to bleed air while the bleeder plug is loose, the use of a one-way valve raises the concern that attention to the bleeder plug may be neglected during fluid replacement and bleed air. In such a case, the plug adapter with a locking mechanism is the best solution. In fact, it is precisely when using one-way valves that it is essential to have a means of preventing the hose from disconnecting from the bleeder plug. [/caption

Go to  (6)