Disc brake system does not change the play amount of the lever or pedal even if the brake pads are worn. The reason why the caliper piston gradually moves out. A caliper piston as such will get dirty easily by brake dust, rainwater, and etc. That's why cleaning the caliper piston is very important when replacing brake pads. Clean the caliper piston regularly for making it last longer.
1. The dirt of the brake piston makes damage the piston seal.
2. For the brake piston cleaning, use brake cleaner or a neutral detergent.
3. Improve the piston movement by metal and rubber lubricant splay
1. The dirt of the brake piston makes damage the piston seal.
The disc brake system is a structure in which the brake piston pushed out by the brake fluid moves the brake pad to pinch the rotor. The brake piston that protrudes from the brake caliper keeps its position, so there is no increase in the play amount of the lever, but the amount of exposure of the piston outer circumference increases as the pad wears off. Then, the powder of the pad scattered by the wear and the rainwater and dust that jumped up during the running will adhere to the side of the piston.
The surface of the steel caliper piston is plated, but it may cause rust if dirt remains on for a long time. Also, when replacing the worn brake pads, push back the ejected piston inside the caliper, but if you push the dirty piston back with the pad powder or dust, it may damage the rubber caliper seal set on the caliper. In order to avoid such trouble, it is important to clean the dirty caliper piston.
・On the piston side, brake dust and sand dust will adhere.
・Leaving the dirt for a long time may cause rust
・When changing the pad, if the piston is pushed back while it is still dirty the caliper seal may be damaged.
2. For the brake piston cleaning, use brake cleaner or a neutral detergent.
The dirt on the caliper piston is caused by burned by the heat of braking when the brake is applied, so when using a parts cleaner, the fast-drying type that stays in the cleaning part for a long time is recommended instead of the highly volatile quick-drying.
Besides, if there is a circumstance where the water of the bucket can be used, it is effective to clean each caliper with a neutral detergent in the kitchen. The degreasing power and surface active ingredients of neutral detergents are strong. To penetrate the dirt that stuck to the piston, most of it will remove by brushing.
To remove the dirt, a soft brush made of a plastic material such as a toothbrush or nylon brush is an absolute requirement. Metal wire brushes that can damage the plating are NG.
Not only the visible part from the front, but also the dirt on the caliper side must be removed well. For dirt on the backside, it is also effective to polish it with thinly cut waste clothes around the piston and rub it in the manner of dry cloth friction. Depending on the shape of the caliper, the entire circumference of the piston may not be cleaned by any method, but avoid pushing back the dirty piston.
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・The part cleaner is recommended by a medium-speed drying type. It is also effective to wash each caliper with neutral detergent for the kitchen.
・When removing dirt, use a soft brush such as a toothbrush or nylon brush.
・Never use a metal wire brush because it can scratch the surface.
・Clean not only the front side but also the caliper side
3. Improve the piston movement by metal and rubber lubricant spray
After cleaning the dirt on the caliper piston, apply lubrication spray for finishing.
The lubrication spray used here is a special chemical that can be used on the contact surface of metal and rubber, and do not use anti-rust lubricants that may alter rubber seals. The special chemical improves the slippage of the rubber seal, and it is useful for preventing rust by putting moderate oil to the piston surface, but the excessive application may cause dirt and dust.
If it is sticky after spraying, wipe it off with waste cloth. In addition to changing the pad, the "squeeze out" which improves the operability by cleaning the pistons and spraying lubricating chemicals, is effective not only for pad replacement but also for regular maintenance of disc brakes. The movement of the piston becomes smooth, and the effect that can be expected to the response of braking operation and better lever touch has been improved.
Since the brake is an important safety part, if you are not confident in your work, It would be better to consult a professional technician or go to a motorcycle shop to check the current situation.
・Lubricating spray for piston uses special chemicals that can be used for metal and rubber
・By performing regular maintenance other than the time of pad replacement, it will improve the pistons' operability and lever touch.
・Applying excessive lubricating spray, dirt and dust will adhere to the caliper piston.
Cleaning the caliper pistons is important.
Simply wash the dirty caliper piston with a neutral detergent to restore function and the life of the caliper seal will last longer. However, half-hearted work can also cause trouble, so do enough simulation and preparation before going to apply. If you are not confident, refrain from taking action, it is better to consult an expert or go to a motorcycle shop.
