To cycle faster, you will most likely require a properly tuned and well-adjusted hydraulic disc. Furthermore, you can maneuver through unseen terrain and corners at incredible speed confidently, knowing you have a brake that is functional and will help you stop quickly. Therefore, it is essential to learn how to adjust Shimano hydraulic disc brake levers.
Unlike cable-actuate brakes, hydraulic disc brakes require minimal tinkering plus maintenance. Usually, hydraulic brakes operate by exerting pressure on the fluid and move to the caliper, which presses against the brake disc. With that said, here are a detailed guide on how to adjust hydraulic disc brake levers.
How To Adjust Shimano Hydraulic Disc Brake Levers In 5 Step
There are five steps involved in adjusting hydraulic disc brake levers, and they include;
- Shimano hydraulic disc brake lever operates using a hand lever, which is also known as a master piston. The piston pushes the brake fluid via sealed brake tubing into slave pistons, which is located at the caliper.
- When inspecting your hydraulic system, do not turning your bike upside down to prevent air from entering the brake lines.
- The Shimano hydraulic disc brake lever comes in two different caliper mounting systems. Furthermore, the body of the caliper might be bolted directly into the rotor mount of fork or frame.
- However, in some cases, the caliper body might be bolted to a bracket, whereas the bracket gets bolted into fork or frame. It is advisable to make use of thin washers when adjusting a caliper body that is directly bolted into the mounts.
- When adjusting the caliper body, place the banjo washer between the forks or frame mount. Afterward, install the washers and then secure them using the mounting bolt. Once you are done, assess the rotor to pad alignment, and if necessary, you might add or reduce washers.
2. How to carry out an adjustment
Aligning a caliper to a rotor is very important for the brake’s performance. The following is the proper alignment for Shimano hydraulic system;
- Always lose the mounting bolt completely for calipers that are mounted on brackets. Once this is done, the caliper will move sideways.
- To maintain pressure as well as secure the pads against the rotor, you need to lower the brake lever. Doing this will move the caliper, ensuring both the rotor and pads are aligned.
- Inspecting both the caliper and the brake pad piston is essential. By pushing the piston to the right and left, you will be able to align the piston to the center.
- To maintain the pressure on the rotor, it is recommended that you tighten the caliper by mounting the bolts.
- After releasing the lever, it is essential to check on the pad’s initial alignment. The pad should preferably clear the rotor without any rubbing. Nevertheless, there are a few instances when tight rubbing might occur, but this should not affect the performance. When your wheel slows down when turning, you should consider loosening the mounting bolt on the caliper to adjust and reposition the pads and caliper.
- When you lose a mounting bolt fully, you can perform fine-tuning on the alignment of the pad and ensuring the other bolt is tight. With this, you will be able to push the caliper, whereas turning the snug bolt.
3. Removing and replacing the brake pad
When replacing or removing a Shimano brake pad, check if the pads have unevenly worn; this will indicate the status of caliper alignment to the rotor. The following is the procedure of removing and replacing the Shimano brake pad;
- Always mount your bike on a stand and take out the wheels.
- Rotate the lever on a handlebar for the upper surface of the reservoir to be parallel to the ground.
- Wipe the lever as well as the reservoir cover. Take off the reservoir cover to get rid of the excess fluid in the reservoir.
- Remove the pad fixing bolt.
- Take out the pads by shoving them away from the hub axle.
- Using a mild solvent and a clean rag to clean the piston area.
- Push the piston into the caliper’s body with a plastic lever like the tire lever. Always push near the center piston and not the edge piston.
- Push the piston back into the caliper’s body once cleaned.
- Install the caliper and assess the alignment between the pad and bolt hole.
- Connect the pad and secure it using a bolt.
- After installing the pad, screw the reservoir cover in place.
- Install the wheels back and test them by squeezing the lever with force. If your lever feels soft, then bleeding will be required. However, when the pads are misaligned, you will have to reset it.
4. Replacing and bleeding of brake fluid
Removing the air trapped from calipers and lines is known as bleeding a hydraulic system. The Shimano hydraulic disc brake levers operate using mineral oil. However, you should not make use of an automotive D.O.T. brake fluid in the Shimano brake system. The following is the procedure of bleeding and replacing of brake fluid in the Shimano brake system;
- Mount your bike on a repair stand and take out the wheels.
- To avoid brake fluid contamination, remove the brake pads.
- Install the brake block instead of pads. You might consider using the Shimano brake block Y8CL18000
- Afterward, rotate your bike for the tubing to have an upward slope from the brake caliper to the reservoir. Furthermore, rotate the lever on the handlebar until the upper surface of the reservoir to be parallel to the ground.
- Fasten a bleed tubing at the end of the bleed nipple found in the caliper. You might consider using a plastic bag in collecting excess fluid at the tubing end.
- Clear all the dirt from the lever while wiping around the reservoir tank. Moreover, at the cap of the reservoir tank unthread the screws.
- Take off the reservoir bladder as well as the cap and fill it to the top.
- At the caliper body, loosen the bleed nipple.
- The fluid level might go down when bubbles appear in the reservoir tank as you repeatedly operate the lever. However, you should continue filling the reservoir tank with fluid. To get rid of the air trapped in the reservoir, make use of a non-metallic lever to collect the brake line.
- Keep the reservoir full of fluid, and as the oil starts to pour out of a bleed tube, you should close the bleed nipple located in the caliper body.
- The lever should be firm and stiff when pulled. However, in case there is any resistance, you should open the screw and carry on operating on the handle and then pump the oil into the system.
- As the resistance of the lever stiffens, close the bleeding nipple and hold on to the lever to main the pressure.
- Use a small adjustable wrench or 7mm wrench in loosening the bleed nipple to open up the system. Once opened, check for any air bubble present in the system
- You should then briefly open the system to get rid of the air bubbles.
- As you add fluid to release, the lever and assess the reservoir tank.
- Once you are done with bleeding, disconnect the hose from a bleed pipe.
5. Resetting the brake pads
The following are the steps you need to consider when resetting Shimano brake pads;
- Mount your bike on a repair stand and take out the wheels.
- Get rid of the pad retention screw and pads. Consequently, use a mild solvent like isopropyl and a fresh rag to clean both the piston faces as well as the interior of the caliper body.
- Make use of a plastic lever like a tire lever to push every piston into a caliper body. Assess whether the piston is moving due to excess fluid in the system.
- Install the pads.
- A floating shim should then be installed. Shimano, part number Y8CL1200, is the most recommended.
- Squeeze the lever recurrently to center align the caliper.
- You should never squeeze the lever when installing the wheel.
- When the center aligning the pads to the rotor, you should use washers. Afterward, secure the mounting using bolts.
- Assess the alignment by squeezing the lever.
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How do you adjust Shimano mechanical disc brakes?
Between the brake pads and disc, the brake motor adjusts the clearances. You should ensure that they are within the range of 0.2mm to 0.5mm. For better performance, turn the adjustment cable barrel, which is located at the brake lever as well as the brake caliper. Adjust both the outside and inside parts simultaneously.
Keep in mind that other than braking, the contact between pads and disc rotor might result when operating. Furthermore, you might not obtain sufficient braking when clearance is high on one side.
When should I replace Shimano brake?
When the braking surface and rotor has a small development, it is a clear indication that you should change your brakes. However, you can measure its thickness before changing, using a micrometer or a digital caliper.
When a rotor is poorly bent, it is recommended you change the brake because rotors tend to bend when they become too hot or damaged during a crash. Nonetheless, in other cases, the bend is not visible, but you can realize it when a part rubs against the brake pads as you turn the wheel.
How do you bleed SRAM hydraulic disc brake?
When dealing with brake fluid, it is highly advisable to protect your hand. When bleeding, the SRAM hydraulic disc brake use two syringes with fresh D.O. T 5 brake fluid. The first syringe should be half full, while the second syringe should be a quarter full. Also, you need to block air from entering while filling the syringe with fluid.
Remove the pads and insert the bleed block safely. Once this is done, take out the caliper bleed port screw and screw in the half-full syringe. Afterward, expose the lever bleed port as you remove the screw and fit the other needle, push the fluid into the system.
When the air gets in the hydraulic brake system, it might lead to poor performance by the brakes. This is because the air in the brake often causes inconsistent system pressure when hot. Moreover, when braking hard, air bubbles might expand, making the lever to pump out. Therefore, you should always get rid of the air present in the braking system by bleeding.
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Last Updated: June 8, 2022