Recently, I’ve heard a lot of small partners react that the brake of light bee x makes a strange noise, which can’t be solved. So I’m writing this article to let you know the causes and solutions of the abnormal noise.
The first thing to say is why only the light bee X version has abnormal noises, while the standard version rarely has abnormal noises?
Here is the difference between the two versions of the brake pad. The normal version is made of resin, which is silent, but prone to heat exhaustion, and the strength is relatively small.
The light bee X version uses a metal brake pad, relatively powerful, heat exhaustion, and durable. The disadvantage is that it is easy to make abnormal noise. This is because metal makes the metal particles in the disc more prone to high-frequency screams when they rub with the disc.
The metal brake pad itself determines its own screaming attribute, but engineers have long thought of it, so many other substances are added to the metal to make sheet to improve braking effect and solve screaming. Therefore, the metal to make sheet can be very quiet!
Since it can be very quiet, why is my still screaming?
This pollutant is not only oil, but also sand and other foreign matters! Oil stains come from various sources, such as the oil on the chain, which is thrown onto the discs, the brakes are leaking, and there will even be a little thin oil stain on the road, which is usually invisible, but when it rains, there will be a layer on the road.
The oil film and the thrown rainwater contain a small amount of oil pollution, so oil pollution is the first source of investigation.
As for the gravel, it is off-road, occasionally passing through gravel roads, etc., occasionally splashing small particles of sand, caught on the pad, resulting in the disc and the pad contact area is too small, or the pressure at a certain point is too large.
The most obvious symptom is that the disc is ground into a deeper groove. At this time, the entire brake system becomes a turntable, the disc is the record, and the sand in the brake pad is the stylus of the turntable. As long as the brake is applied, abnormal noise will be emitted.
Check whether the mounting screws of the disc are installed in place (the original bike has not been dismantled, this will almost never happen), check whether the caliper is installed correctly, whether the caliper and the disc are in a straight line, whether the caliper fixing screw is tight, and the shaft.
This situation is generally manifested as when the car is braking, the whole car is feeling high-frequency vibration, and the hand feels a little numb.
3. Poor running in
Wrong running-in will cause the brake pad to engrave incorrect braking marks on the disc. These marks are like a record, which will record the abnormal noise.
When the mark becomes deeper and deeper, it will cause abnormal noise. It is also the problem of many new bikes that start to make abnormal noise after riding for a few kilometers, so it is especially important to master the correct running-in method!
For the brake pad, there will be abnormal noise when it is used to finish grinding, which is used to remind the driver that the brake may be abnormal and needs to be inspected and maintained in time. For such abnormal noise, it can be directly exchanged.
Understand the above four points, it is easy to solve the problem of abnormal noise. The following is the focus of the article, how to solve the problem of abnormal noise!
Step 1 disassembly
Remove the front wheel,
first remove the locking screw (red), and then remove the shaft (yellow).
After removing the front wheel, you can directly remove the screws of the disc. Here, a T25 torx wrench is used. Note that you should try to use a T shape instead of an L shape.
To use it, you should use a long tip, press down and twist it firmly, otherwise it is easy to slip.
We saw a lot of tunnels of different depths on the disc that was removed. These are the traces of sand and stone, and it is also one of the culprits of abnormal noise!
Now remove the brake pad, first loosen the caliper fixing screw and remove the caliper.
Remove the limit buckle (red) and remove the fixing screw (yellow) of the backing plate.
Push the brake pad from top to bottom to remove it.
Observing the brake pad, it was found that there were many deep scratches on it. Part of these scratches came from the metal pad itself, and some came from sand and gravel.
The second step is cleaning and polishing
For cleaning, we use strong oil-soluble agents, you can choose by yourself. Please wear gloves when cleaning to avoid direct skin contact with strong oil-soluble agents. Strong oil-soluble agents are corrosive!
Spray the oil-dissolving agent, wait for a while, you can see that the cleaning agent turns black, indicating that the oily impurities are dissolved, and then clean it thoroughly.
Note here that you must thoroughly wash your hands first, and avoid touching the disc and the brake pad with your hands, which may cause secondary pollution.
Please hold the cleaned disc like this, never hold the outer ring directly with your hands!
After wiping the water with a paper towel, you can start sanding.
At this time, if you have a power tool, just use the power tool to polish it, if not, use 200 grit sandpaper to polish it, just polish the outer ring of the disc!
There is no skill in polishing, as long as the original grooves and tunnels are polished away. Pay attention to electric sanding, please wear a mask to prevent metal particles from being inhaled into the lungs.
After polishing, the original grooves are gone, pay attention, both sides must be polished!
Use the same method to polish the brake pad, pay attention, do not over-grind the pad, otherwise it will affect the service life!
Finally, check that the thickness of the brake pad should be greater than 3mm (the new is 4mm).
The thickness of the disc is greater than 1.75mm, below this limit, it is recommended to replace it. After checking, you can start to restore the installation.
Follow the steps of dismantling before, and put it back step by step in reverse!
There are a few special points here!
Tighten the disc screws first, but do not use torque. After all the screws are installed, gradually increase the torque, and tighten the screws in order (green) instead of orderly (red). ), directly tighten!
Install the wheels first, and then install the calipers. The wheels first torque the shaft, and then install the 4 fixing screws!
When installing the caliper, do not directly tighten the fixing screws. First, install roughly in place, squeeze the brake lever, let the piston and the disc automatically match the gap, and finally pinch the brakes and fix the caliper screws. After fixing, the disc may be slightly rubbed. Disc phenomenon, and then manually fine-tune! Make sure that there are gaps on the left and right sides of the pad, do not rub the disc, and keep the disc and the pad parallel.
If there is a small part of grinding but other places are not grinding, it means that the disc is slightly deformed. Use a disc corrector to correct it slowly. Remember not to be too impatient. In this process, work slowly and carefully!
Since then, all installation is complete!
Earlier I compared the disc to a record, to make the pad a stylus, then at the beginning of the break-in, we use the brake lightly, which will guide the disc and make the film smoother. At this time, if foreign matter enters, For example, sand will cause a deep groove to be ground, and this groove is one of the culprits of abnormal noise! It is precise because of this that the above polishing steps are needed!
So how to properly break in the brakes?
The correct way to run in is to make a quick emergency stop and brake vigorously under the premise of safety.
At this time, the brake will not scream (it may scream at first, don’t worry, it will disappear soon), Until the brake makes a rustling sound, the brake gradually becomes very powerful, indicating that the running in is very good.
Generally speaking, 1-2 kilometers is enough to complete the entire running-in process. At this time, abnormal noise should have said goodbye to you!