Want to graduate from rookie, will you handle simple disc brake abnormalities?

Now disc brakes are basically the standard equipment of commercial models, and the performance of disc brakes is recognized by everyone, but hydraulic disc brakes

The mechanical structure is more sophisticated and complex

, a slight discomfort can also appear such and such problems, we can’t go to the store to find a problem


, which is cumbersome and costly.

If there is a problem, you must first understand and judge by yourself, know which problems can be solved by yourself, and which faults need to be called to the car shop in time. Today, I will take you to see some matters in the maintenance of hydraulic disc brakes.

First, the brakes are too tight

Newly purchased bicycles or cars with replacement disc brakes often have the problem of making the gap between the pieces too small, jerky and too tight, which is a normal condition and can be solved by scientific running-in.

The correct running-in method is:

Choose an outdoor flat and open road, cycle the bicycle to a speed of more than 20km/h, brake hard to the walking speed, that is, about 5km per hour, repeat 20 times; Then when riding the bicycle to a speed of about 30km/h, brake until the brakes die, repeat 10 times, and the run-in will end, and you will feel the braking effect getting better and better.

Second, the brake abnormal sound

The problem that causes abnormal brake noise is not complicated, mainly due to improper installation position or caliper mixed with sediment and foreign matter. We solve them sequentially by elimination.

Step 1,

Eliminate the position problem to confirm whether each part is installed correctly, first check whether the disc is located in the center of the two pieces, and adjust the left and right positions through the knob on the caliper; Then check whether the disc is deformed and deflected, and the slight deformation can remove the sheet or replace it with a new disc; Finally, check whether the wheel set is installed correctly, and if there is a deviation, the wheel set must be reassembled.

Adjust the caliper position via the knob

Step 1 is fine, and then proceed to step 2

, clean the caliper disc and replace the clip. First, we can remove the tablets, wipe them clean with water or a liquid mixed with alcohol, and then dry them with a paper towel; Secondly, check whether the tablets are stained with oil and replace them immediately if necessary.

The disc should be kept smooth and free of oil

Remove the slices and discs and wipe them clean

Third, the brake system is full pressure

Oil pressure disc brake saturation is too much oil injection in the oil circuit or suck in water vapor, especially DOT brake fluid has strong moisture absorption, over time, the pressure of the oil pipe that absorbs moisture continues to rise, resulting in smaller and smaller gaps and poor rebound, then it is easy to have poor wheel rotation, a brake lock, resulting in potential danger.

First of all

, we can take a new oil change, which is suitable for the vehicle has not ridden for a long time, and more than half a year after the last oil change, the oil quality has dropped significantly, when the brake and the disc will rub excessively, so the efficiency of replacing the new oil is better; Or, properly drain the oil, at the brake handle oil injection hole, unscrew the oil injection screw, then too much oil will naturally overflow, wipe the oil flowing out with a paper towel to tighten the screw, if the wheel still cannot rotate smoothly, you can repeat this step until the wheel rotates smoothly.

Fourth, the brake lacks oil mixture

Due to the damage of the oil circuit, the disc brake will lack oil or mix with air, which will lead to soft handle and weak brakes, then we need to exhaust air and replenish oil. At present, except for Shimano hydraulic disc brakes, which use mineral oil brake fluid, most other brands use DOT oil. Mineral oil and DOT oil after moisture absorption boiling point are low (such as DOT4 dry boiling point 230 degrees, wet boiling point 155 degrees, DOT 5.1 dry boiling point 270 degrees, wet boiling point 190 degrees, the so-called wet boiling point is the boiling point after mixing moisture, the more water content, the lower the boiling point), resulting in frequent braking under the oil circuit heating and boiling after damage to the oil pipe, especially the oil pipe connected to the caliper, more easy to leak oil and mixed with air.

At this time, we can use oil replenishment to solve the problem

, unscrew the oil injection screw, if there is air will naturally be in the top of the oil circuit, then you can use a needle syringe to inject the corresponding oil and fill it. If mineral oil disc brakes are used, you can choose discs with better heat dissipation to avoid boiling oil leakage.

Mineral oil disc brakes rely entirely on discs for heat dissipation

The above solutions to common small problems of hydraulic disc brakes, I hope to help you, if you have more questions or problems about hydraulic disc brakes, it is recommended to consult the local car shop, so as not to cause adverse consequences without trespassing.

Hydraulic disc brakes are becoming more common

Can you rule out simple exceptions?

When you use disc brakes,

What problems have you encountered, how have they been solved!

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