BICYCLE HYDRAULIC BRAKES, BLEEDING THEM
Hydraulic brakes on a bicycle require constant care and maintenance. In order to ride a bike as safely as possible, the braking system must function properly. And for the hydraulic brake to provide maximum safety, it must be properly bled. Bleeding hydraulic disc brakes is a serious and responsible job, so you need to approach it responsibly.
HYDRAULIC BIKE BRAKES: ALL THE PROS AND CONS
Hydraulic brakes on a bicycle act like their mechanical counterparts (disc and rim brakes). The principle of operation differs only in that the mechanical brakes are actuated using a cable, and the hydraulic ones operate using a special hydraulic line.
With the help of this hydraulic line, the brake levers and the brake mechanism itself are connected, which can be either a mechanical disc or V-brake pads.
The fact is that the hydraulic line is filled with oil or pressurized brake fluid. The hose has a cylinder at each end. When the brake lever is pressed, through the brake cylinder, the force is transmitted to the brake line and acts on the second cylinder from the other end of the brake line.
This cylinder acts on the rim or disc brakes, depending on which brakes you use. If your hose is filled with brake fluid, remember that this fluid contains poisonous substances and will corrode paintwork. For this reason, brake fluid is often replaced with oil.
Pros and cons of hydraulic brakes.
The main advantage, thanks to which the owners of hydraulic brakes use them, is very precise braking, precise and fast response.
If you use mechanical brakes for a long time, then they will either wear off the pads or break the cables. If you use hydraulic brakes, then these problems will not concern you.
In a brake system of this type, the main thing is that the tube with the brake fluid or oil does not bend, but if the tube is damaged, then the brakes may completely cease to perform their functions.
Because the hydraulic braking system provides the cyclist with a better brake feel and responsiveness to the brake lever, hydraulics are often fitted to powerful bicycles.
For example, bicycles designed for freeride or trial riding. Bicycles of this class are used for extreme riding, in which the responsiveness of the bicycle brake system to the actions of the cyclist is one of the most important points.
Among the shortcomings, it is worth noting the complexity of repair. For example, if you punctured the hydraulic system somewhere far outside the city, then this is a significant problem, the elimination of which is very, very problematic.
If this situation happens during any competition, then most likely you will be in last place. Also, the disadvantages include the fact that it will be quite problematic to install the trunk with the hydraulic system installed, because the hydraulic system interferes with the trunk.
Also, there are some problems with removing and putting the wheels on the bike. you should perform these actions very carefully, as you can damage the hydraulic system, but here, of course, there is little good.
BLEEDING HYDRAULIC BRAKES ON A BIKE
Bleeding hydraulic brakes on a bicycle has nothing to do with discs and pads, so we remove them. In this case, the main work is done with cylinders and tubes. So let’s get started.
- First, you need to unscrew the main cylinder and fix it in an upright position.
- After that, we remove the top cover on the master cylinder. There is a membrane under the cover. There is brake fluid under the diaphragm. It is worth noting that you need to use exactly the fluid that is poured into your brake system. If another fluid enters the brake system, there is a risk of brake failure. But more importantly, damage to the entire brake system can occur, and it is not cheap to repair it. The bleeding of each hydraulic brake system is individual. You can use your own methods, however, you need to be extremely careful here and be sure to check the brakes before leaving. Consider a shimano brake system. To pump it, use a special tool attached to the main cylinder body. The liquid is collected in its bottle. It looks like a container with a tube, which is adapted to the hydraulic system.
- Fill the syringe with liquid. Again, the liquid should not be of any other type. To bleed the brake system, you need to fill the syringe as much as possible. There should be no air bubbles in the syringe, because it is to get rid of them that pumping is done.
- The next step is to inject fluid with a typewriter. During this operation, the valve sometimes jumps out of the body, for this reason, you need to use a special gasket or something else to prevent the valves from coming out of the machine body. You need to bring the liquid to the very end of the tube and put the tube over the inlet nipple. Now we open the inlet nipple with a key, after which, without haste, we can perform the fluid supply. When pumping fluid through the system, it is important that there is no leakage. Brake fluid can corrode paint. Mineral-based fluid is harmless; when using a different composition, it is better to protect the frame with something. When pumping fluid, tap the tubes with a wrench or other tool to help air escape from the main cylinder body. You need to stop feeding liquid in advance.
- After closing the inlet nipple, remove the tube. Check for valves in the machine body. The position of the fluid should be flush with the top edge in the main cylinder body. There must be no air. If necessary, the diaphragm in the master cylinder must be free of dirt.
- Now, you need to put the membrane on top and close the lid. Clean the steering system of brake fluid residues with brake disc cleaner, if required. The clipper must also be cleaned. You can use technical napkins, from which there are no lint. It is better not to use an old rag, small particles, fluff from it, can get on the brakes, which can cause leakage or pollution.
Wash your hands before installing pads in the brake hydraulic system. You have been pumping the brake system and your hands are probably in the remaining brake fluid. You don’t want to get the pads dirty when you install them in the brake system.
You need to work with the brakes with well-washed hands, because oil, grease, brake fluid can stain the pads, and you will have to buy new ones. And it costs a lot of money.
I would like to note that if the speed of the bike is high enough, then the hydraulic brakes must be used extremely carefully.
How to set up hydraulic brakes on a bike. Adjusting the brakes on a bicycle
Adjusting the brakes on a bicycle should be carried out regularly. such maintenance will guarantee the safe operation of the vehicle. There are two main types of brakes on modern bicycles. rim and disc brakes, but disc brakes can be mechanical or hydraulic. The type of brake system installed on a particular bike will determine the process of their maintenance.
How to check and adjust the brakes
There are clear instructions for checking and adjusting the brake system of a bicycle. If you adhere to it, then the whole process will take little time and will be effective.
Procedure for checking and adjusting the brake system of a bicycle:
- Dry brake test. It is necessary to raise the front wheel and, having unwound it, press the left brake lever. If the wheel comes to a sudden stop during this test, the braking system is in order and no maintenance is required. It is worth considering one nuance. if the brake lever touches the steering wheel, then you just need to pull the cable. The operation of the rear wheel brake system is checked in the same manner. To tension the cable, you need to use curly bolts. just tighten them a little and, if only minor adjustments are required, this will correct the situation. It often happens that such a minimum adjustment does not work. in this case, we look where the end of the cable is on the bike (it is always longer than necessary in advance), unscrew the bolt that holds it. It remains only to tighten part of the cable with pliers and tighten the bolt, applying the possible force.
- Checking the brake pads. After the brake levers have been tested, the condition of the brake pads should be carefully examined. However, the order of action can be changed. first work with the pads, and then with the handles.
The brake system setting is different for rim and disc types, since different rotating mechanisms and pads are used.
Adjusting the rim brakes
Mountain bikes use a v-brake braking system. using this as an example, we will consider the principles of tuning, since it is also available on other bicycles with rim brakes. The difference can only consist in a different arrangement of bolts and screws that will need to be tightened / tightened.
Note: it is important to observe three main rules:
- the pads should be parallel to the rim;
- the gap between the rim and the block should not be more or less than 1 mm;
- the pads should be symmetrical in relation to each other.
How to achieve these guidelines when adjusting rim brakes on a bicycle:
- You need to find a hex nut. it fixes the pads. To loosen it and set the brake pads in the desired position, you will need to press the brake lever and watch how the shoe touches the rim. By releasing the brake lever, the shoe can be set to the desired position. it moves up, down and at an angle.
- The distance between the shoe and the rim of the wheel should not be more than 1 mm, although in some models of bicycles there are also 2-3 mm. exact information about a specific vehicle can be obtained either from the instructions for it or on the Internet for technical characteristics. It should be noted that braking of the wheel should occur even with the minimum pressing of the brake lever. That is, if the wheel stops only when the brake lever is fully pressed “all the way”, then this is incorrect.
After carrying out all the specified work, it is imperative to check the operation of the brake system. First, this is done at idle speed. lift the front wheel up, spin it up and press the handle sharply, then do the same with the rear wheel. The next step is to check the operation of the brake system “in action”. get on the bike and ride 3-5 meters, braking sharply. If the bike has stopped even with a minimal pressure on the brake lever, then the system has been serviced correctly.
Setting up disc brakes
As a rule, adjustment of disc brakes consists in periodically tightening the cable. But often you have to replace the pads, however, on disc brakes they wear out longer than on rim brakes. First you need to find out which specific disc brakes are installed on the bike. brake pad adjustments for hydraulic and mechanical systems will differ.
Experts recommend taking note of the following points:
- If there are hydraulic disc brakes on the bike, then replacing the pads may not be necessary. they are able to do it on their own. But one caveat should be taken into account. if the hydraulic system is closed, then you will have to adjust the pads in manual mode. for this, special valves are provided.
- If you have to adjust disc mechanical brakes, then you will need to pull the cable according to the above instructions and check the location of the pads. the distance between them and the disc should be within 0.2-0.4 mm.
- In order to adjust the pads with disc mechanical brakes, you need to use special bolts. by tightening them, you can see how the pad moves. You need to be especially careful when setting the distance between the pad and the disc. 0.3 mm is too small, it’s easy to make a mistake.
Be sure to check the operation of the brake system in action after the work is done. ride your bike for a few meters and try to brake. If the cable is too tight, or the pads are too close to the disc, then too sharp braking will occur. this is a “surprise” in which the cyclist begins to move forward, but without his vehicle. Therefore, when driving for a test, you need to be extremely careful and careful, if necessary, the disc brake system is adjusted again taking into account previous errors.
How to adjust disc brakes on a bicycle: techniques for hydraulics and mechanics
Normally, the disc brake stops the wheel as quickly as possible, allowing the force to be dosed on the verge of blocking the rotor. Deviations appear after replacing the cable, pads and overhaul. However, the settings are violated during long-term use, as well as after removing the wheel, for example, to seal the bicycle camera at home. How to avoid the famous rotor shuffling, how to eliminate braking, and, in the end, how to restore the factory braking character. these and other questions are answered by the editorial staff of Autobann magazine.
Before adjusting: preparing for tuning
The decision to adjust disc brakes on a mountain or road bike will only be successful if brake diagnostics are included. By the way, the diagnostic measures for hydraulics and mechanics will be different. How hydraulic brakes on a bicycle differ from mechanical ones. we already had a conversation.
In short, in the hydraulic circuit, both pads push the fluid, acting on the caliper pistons, which results in clear modulation and easy handle travel. And in mechanics, only one friction lining is movable. It is brought to the disc by pulling the cable with the brake lever.
However, whatever the brake drive is, it is worth checking:
- Rotor for deformation. For 100% confidence in the flatness of the disc, it is better to unscrew it and put it on a flat surface. A rough estimate can be made while on the bike by rotating the wheel and estimating the distance to both pads through the slot in the caliper. Friction linings must be equidistant from the disc in any position.
- Brake pad wear and integrity. Remove the pads by removing the cotter pin and assess the residual thickness of the friction material. The surface in contact with the disc must be free of pits and dents.
- Cleanliness of pads and rotor. The presence of oil traces and accumulations of dirt on their working surfaces is not allowed. To clean them, you can use fine sandpaper (for example, “zero”) and rags soaked in any cleaner (acetone, ammonia.).
- Wheel hub location in frame / fork dropouts. The bushing should fit freely into the seat and abut against the counter surface of the frame or fork. Distortions in the installation cannot be avoided, but they should be minimal, practically invisible. Micron skewing is immediately audible on the brakes in the form of rotor shuffling. This is why disc brake adjustments are required after re-mounting the wheel.
It will not be superfluous to look at the state of the drive. With cable disc brakes, check the cable integrity. The end should not be unwoven, and the service life should not exceed 3 years. When replacing the cable, change the shirts. It is not necessary to lubricate it, but if you decide, then do it only with the help of a special lubricant that does not attract dust.
Nothing should leak on the hydraulics. Weaknesses are connections:
- Master cylinder. hydraulic line.
- Brake Lever. Master Cylinder.
- Brake caliper hose.M
These joints received a weak status due to the use of cuffs, which dry out over time and leak.
How to adjust disc mechanical brakes on a mountain bike
Mechanics are gradually becoming history. Now it can still be seen in the budget line of Russian Stels, Forward and Stern. Considering the price, there is no need to talk about the belonging of brake system parts to such global brands as Shimano and Sram. Usually this is some kind of noname kit that has a minimum of settings.
Another nail in the list of disadvantages of mechanical disc brakes is that they need adjustment more often. This is because one of the pads is motionless. As it is erased, the distance between it and the disc automatically increases. Meanwhile, fluctuations in the values of this clearance should be insignificant, otherwise the friction linings will wear unevenly, the quality of deceleration suffers.
Checking the readiness of the system for adjustment
So, first you need to make sure that:
- The adapter to which the caliper is attached is well secured to the frame or fork (bolts are tight).
- The already tested rotor is securely fixed with screws on the hub.
- The wheel is installed on the bike, the eccentric / nuts are tightened.
- The lamb for adjusting the cable tension is unscrewed no more than 1.5 turns (located next to the handle or caliper).
- The cable is fixed on the movable arm of the machine.
Working with a caliper
Adjusting mechanical disc brakes on a mountain bike is a two-step process: adjusting the caliper and adjusting the brake lever. To adjust the caliper means to set the pads symmetrically relative to the disc, while the gaps should be minimal.
When adjusting the caliper, it is important to follow the sequence of actions:
- Center the clipper. Loosen the bolts securing the caliper to the adapter and, moving the caliper, find its position in which the pads will be equidistant from the disc and completely parallel to it. After centering the machine, pull it to the adapter, observing the rule of uniform tightening: turn one bolt ¼ turn, then the other also ¼, and repeat the described procedure again with the first and second fasteners.
- Align the clearance between the fixed pad and the disc. Any grade of mechanical disc brake caliper has a bolt or adjusting wheel to move the fixed pad closer / away from the disc. Here the task is to use this adjustment in order to bring the block as close to the rotor as possible, while maintaining the clearance. The easiest way to do this is to move the friction pad close to the disc, but so that it does not bend it, and loosen the bolt a little to get a small gap.
- Adjust the clearance between the moving shoe and the rotor. On serious kits, a special adjustment is provided for this. a bolt that moves the block regardless of the tension of the cable. On cheap bikes, this setting is combined with the cable tension. The task is to set the same gap as between the fixed friction lining and the disc.
Council. Adjust the clearance so that the friction linings grip the disc tightly in the middle of the brake lever travel. To do this, you will need to adjust the tension of the cable using the wing and the position of the fixed shoe (in order to maintain symmetry about the rotor).
Note. Caliper centering can be skipped if this operation was performed earlier and the wheel was not removed.
Adjusting the brake lever travel
This adjustment allows you to adjust the position of the handle when the brake engages. There are no specific recommendations on this matter. Someone is more comfortable for the bike to brake at the slightest pressure on the handle, someone more like the presence of a small idle and a dead grip in the middle of the lever path.
This adjustment is carried out using a screw located in the brake lever housing. The final adjustment of the severity of the brake seizure is made by the cable tension thumbscrew.
Attention! After completing all adjustments, check that the pads are equidistant from the rotor. It is possible that the fixed friction lining will need to be adjusted.
Particular questions on mechanics. How to release the disc brake on a bicycle
It is enough to screw in the cable tension drum a certain number of turns. If its stroke is not enough, unscrew the nut securing the cable to the caliper and loosen its tension. Option “so-so”. unscrew the handle adjustment bolt.
Don’t forget about the fixed shoe. Moving away the movable friction lining with a cable, move the static one, so that symmetry with respect to the rotor is maintained.
How to pull
Proceed in the reverse order of loosening the cable and you will get the desired result.
How to make the brakes brake well
Use good quality pads and center the caliper against the rotor in a timely manner so that the disc bends as little as possible.
Adjusting hydraulic disc brakes on a bicycle with your own hands
The hydraulics are called self-adjusting. Where this status came from is unclear. The centering of the pads relative to the disc can also get lost here. And the shuffling of the rotor itself is one of the first complaints from owners of even new bikes.
In general, setting up hydraulic disc brakes on a bicycle is easier than using cable brakes. But drawing a parallel between adjusting the brake mechanism and cleaning the chain, we can say that working with the brakes is still more difficult than washing the chain at home.
The main goal is the same: to center the caliper, check if the pads are equidistant from the disc, adjust the handle stroke, if its design allows it. It is necessary to carry out the adjustment step by step:
- Loosen the bolts securing the caliper to the adapter.
- Clamp the brake lever to the stop and fix it in this position using the available means (wire, electrical tape.).
- Check the position of the rotor. It should be located exactly in the center of the caliper slot. If the disc is bent, then the pads are not equidistant from it. The required position of the friction linings and the rotor can be achieved by bending the disc in the opposite direction from the observed bending. Fluid will flow from one piston to the other and the pads will align.
- Tighten the caliper mounting bolts alternately. Use the 1/4 turn tightening technique found in the Mechanics Set-up Technique.
- Adjust the position of the handle using the screw on its body.
Adjusting the bike’s hydraulic brakes and replacing the pads
The principle of operation of hydraulic brakes on a bicycle is to transfer pressure through the hydraulic line from the brake master cylinder to the brake cylinder in the caliper, which in turn moves the pads. The brake fluid is not compressed, therefore such a system is more reliable and efficient than a mechanical one.
On the other hand, the hydraulic lines and the entire braking system require careful attention and constant maintenance, and therefore repairing and adjusting hydraulic brakes often seems to be a difficult task.
How to adjust everything yourself
Adjusting the hydraulic brakes may be necessary if you notice extraneous sounds while driving. squeaking or rustling. A simple test will help to make sure that the adjustment is necessary: lift the bicycle wheel and spin it. If the pads touch the brake disc, the wheel will quickly stop spinning.
The relative position of the pads and the rotor must be very accurate, because this affects the brake performance. To check the position of the disc in the typewriter and the position of the pads, place a white sheet under them and, if necessary, direct a bright light on it. against such a background it is easier to notice deviations.
Adjust the hydraulic brake as follows: 1. Loosen the caliper mounting bolts as much as possible so that it can move freely to the sides.
Squeeze the brake lever so that the pads are fully pressed against the rotor.
Check the position of the pad valves. they should be symmetrical, at the same distance from the rotor. Move the caliper slightly to the left or right if necessary.
Without releasing the brake lever, tighten the caliper mounting bolts.
Release the handle and check the brakes. Ideally, the pads should be at a minimum distance from the brake disc, but not touching it.
If you notice that one pad is located closer to the disc than the other, but the rotor itself is perfectly centered in the machine, do the following (preferably two people): press the disc against the more protruding pad and apply a little brake. Due to the fact that one valve works more than the other, they will align and the problem will be eliminated.
The final touch is to set the position of the brake lever relative to the steering wheel. Sitting in the saddle, check if you feel comfortable using the brake lever and if you can quickly press it in an emergency. If the knob is too far for you, tighten the adjusting hex a little more. this will bring the knob closer, but at the same time the pads will move closer to the rotor. The main thing here is not to overdo it and not make the stroke of the pads too small.
Video demonstrating the entire adjustment process:
Replacing brake pads
Poor operation of hydraulic disc brakes can be due to the following reasons:
- damage or contamination of the hydraulic line or ingress of air into it;
- complete abrasion of the brake pads;
- dirty pads or disc.
In the first case, replacement of the hydraulic line or bleeding of the hydraulic brake is required, with the second and third cases it is easier to understand.
First, take a close look at the brake pads. All manufacturers prescribe their minimum thickness, at which the braking performance does not decrease. By the way, uneven wear of the left and right pads indicates that the rotor is not centered relative to the caliper.
As the pads wear out, the valves move closer to the rotor, so before installing new pads, you should slightly push them apart and re-adjust their position. The entire replacement procedure consists of the following sequence of steps: 1. Place the bike on a repair stand and remove the wheel.
Remove the retaining ring and unscrew the fixing bolt.
Pull out the old pads away from the hub axle. Remember the location of the return spring between the pads. it releases them after the end of braking.
Thoroughly clean the valve surfaces and the inside of the caliper. Use a lint-free technical cloth and a mild cleaner such as isopropyl alcohol.
Using a plastic lever, such as a tube changer, press both valves into the caliper. To install the valve correctly, you need to press on its center, not on the edge.
Install a return spring between the new pads and insert them into the machine.
Tighten the fixing bolt and install the retaining ring.
Clean the brake disc and replace the wheel. Check the correct position of the rotor, pads and the functionality of the entire system.
New pads may require a period of “adaptation”, so at first the updated brakes should be used carefully.
it should be said that all work should be done with clean hands. Also, to keep the brakes less dirty, you should close them when lubricating the chain. With a comprehensive bicycle service, the brake system is repaired last.
How to set up hydraulic disc brakes
You may not have read our article on tuning mechanical disc brakes, which is understandable if you have hydraulics. Still, we recommend that you look into it, there is interesting information about the types of brake attachments and adapters.
Now let’s get down to customization! Today’s test subjects will be the Saint M810 brakes, which have a PM (Post Mount) mount. Now the vast majority of brakes on the market have this type of mount, IS brakes are only found if you are buying antiques. One of the nice things about hydraulic disc brakes is that they are much easier to set up than mechanical brakes when the brake rotor is not bent. This is due to the fact that both pads press the disc from both sides at the same time.
Prepare a 5mm Allen tool. Secure the bike in a bike rack or simply flip it over (remember to put cardboard or some old cloth under the handlebars and saddle if you are flipping).
Spin the wheel and listen to the disc, it should rotate freely without touching the pads. If the disc touches the pad, check which one. To do this, look at the gap between the disc and the pad.
If the disc is not curved and constantly rubs against one of the pads, then unscrew the 2 caliper mounting bolts.
Pressing the brake lever several times with one hand, leave it in the clamped position, and with the other hand, gently tighten the caliper mounting bolts.
Make sure your disc is not rubbing against the pad anywhere. Finally tighten the caliper mounting bolts. Profit!
If you are unable to adjust the brakes, as the rotor constantly strikes against one or the other pads, then it is quite possible that you have a curved rotor. There is a special key to align it:
If there is no wrench, you can try using a minimally tightened adjustable wrench. Adjust the adjustable wrench so that the disc fits exactly between the lips of the wrench.
Using the caliper as a bend detector, look in which direction the rotor is deflected and drive into the rotor at this point by slightly bending it in the opposite direction. You should not be zealous and in a hurry, accuracy is important here.
It is also possible for you to clean and lubricate the pistons if they do not come out evenly. To do this, remove the caliper, remove the pads from it and press the brake lever several times. Be careful and watch how much the pistons are out. You only need 2-3 millimeters on each so that you can drip some brake fluid or mineral oil from their end. Attention! Use only the fluid that is in your brakes! In our case, this is mineral oil.
After the pistons are lubricated, return them to their original position by gently pressing on them with a plastic “spatula” for rubber bead.
How to change the brakes on a bike
The design of the bicycle has been improved over a long period. Particular attention was paid to the creation of a braking system that must be reliable and effective in use.
Disc brakes are a common design with a combination of control levers, drive and brake pads. Timely maintenance can significantly extend the service life of the brake system, eliminate the possibility of damage.
Advantages and Disadvantages of Disc Brakes
Many people think that disc braking is a progressive step in the bicycle industry. The design is similar to that installed on a car. The use of discs eliminates the likelihood of rim wear.
Other benefits include the following:
- Eight rim does not affect the efficiency of the braking system.
- It is possible to use the system in harsh conditions.
- Clear modulation.
- Longer service life.
- Disc design does a good job with a lot of dirt.
- Modulation stable, no periodic maintenance required.
In many cases, the structure can last for several seasons, but even with careful treatment and inactive riding, maintenance will be required.
The disadvantages of the design include the following:
- The entire system and individual components are expensive.
- The design cannot be called universal in application.
- Most of the options are not DIY repair.
- Heavy enough weight.
When do you need to change disc brake pads??
It is important to choose the right moment when you need to replace the pads.
Among the features, we note the following:
- Most versions can last no more than 15 thousand kilometers.
- Expensive structures serve about 30 thousand kilometers due to the use of special alloys.
The above information defines what is important to keep track of mileage.
The wear rate depends on the following points:
- Riding style. Difficult ascents and descents negatively affect the life of the braking system.
- External influence. Shocks and other impacts can cause defects that reduce the service life.
- Incorrect adjustment of the device also negatively affects the condition of the pads.
Replacing disc brake pads
The ability to periodically repair and maintain brake discs can significantly save.
Due to this, you can also:
- Eliminate the possibility of system damage.
- Reduces the risks of active skiing.
The mechanical braking system is very widespread.
It has the following features:
- The force from the handle is transmitted by means of a cable. This element is made using stainless steel, which is characterized by increased resistance to high humidity.
- From time to time, the cable should be pulled up. This is due to the fact that natural stretching of the metal occurs under the influence of the applied force.
- The brake pads are located in the caliper. A similar assembly is also made of stainless steel.
- A return spring is installed that returns the pad to the reverse position.
The adjustment is carried out by twisting the cable. The braking surface must be clean, otherwise the braking performance will be reduced.
The hydraulic system is much more complex.
It consists of the following elements:
- Tank with special fluid.
- Hydraulic line. It is represented by a special tube with increased tightness. Air intrusion causes reduced efficiency.
- Drive cylinder.
- The brake piston, which creates pressure.
The procedure for changing the pads is quite simple. The instructions for carrying out the work are as follows:
- The caliper is removable, which simplifies the task.
- You need to carefully straighten all fasteners: retaining rings, wiring, small adjusting bolts.
- The next step is to remove the old pads and install new ones.
- Next, the pads are fastened, after which everything is installed in the old place and the reliability of the fastening is checked.
How to extend the life of your brake pads?
Many people are looking for information on how to extend the life of brake pads, due to which the speed is reduced.
The duration of operation can be extended as follows:
- The surface is thoroughly cleaned at the time of operation.
- Mechanical defects must not be allowed.
- Use only original products.
Compliance with the recommendations allows you to reduce costs. Good systems will last for a long period, it all depends on the correct maintenance and design features.
The design features of the disc-type brake system determine the proper reliability when operating in a variety of conditions.
Vibrators do not lose popularity. Ease of maintenance, cheap consumables and unpretentious operation. an excellent option for those who use the bike primarily for moving, without extreme and overloading.
The principle of operation is simple. when pressed, the brake lever pulls the cable (G), which moves the brake levers (I), pressing the pads (J) attached to them against the wheel rim. When the handle is released, the levers return to their original position, installed on them by springs. In this article we will analyze how to set up and adjust rim brakes:
Checking the condition of the brakes
First of all, we “unfasten” the brake, as shown in the photo.
Check how the cable (G) moves in the shirt (A) by pressing and releasing the brake lever and pulling the cable back with your finger. the movement should be free, without delay. If the cable pulls hard, it may be damaged, the shirt or cable guide (C), or dirt has accumulated inside the jacket or cable guide. They must be removed and cleaned or replaced.
Check the condition of the pads (J). Grooves for the drain of dirt should be visible on them (the block should not be smooth). Worn pads without grooves must be replaced. Check that the pads are complete with washers and that they are correctly installed.
Observe the order of washers when installing new pads.
The brake levers (I) must rotate freely in their seats and spring apart after compression. If the movement is difficult, the brake during operation may get stuck in the closed position and rub the pad on the rim. In this case, you can remove the levers from the seats, clean and lubricate the contact points and reinstall.
When installing, make sure that the protruding pin on the arm fits into the hole in the frame, and that the hole on the left and right arm is the same.
Adjust the position of the pads
“Fasten” the brake by squeezing the levers and placing the cable guide (C) in the stop (D). Loosen the shoe fixing bolt (K) with a hexagon. We press the lever with the block to the rim and set the block so that it:
- adhered to the rim with the entire surface
- did not touch the tire
- parallel to the rim
In this position, the block must be fixed by tightening the bolt. When tightening the bolt, the shoe may move and must be corrected. It will be easier if you find an assistant who will grip and hold the brake lever while you tighten the bolt.
If your brakes squeal, try the following.
Before tightening the bolt, place a folded sheet of paper under the rear (in the direction of travel) of the shoe, then tighten the bolt. So the pads will be smoother to press against the rim during braking (first by the front, then by the rear) and will not “creak”.
We do similar operations with the second block.
We set the levers symmetrically
For the left and right shoes to wear evenly, they must be at the same distance from the rim. Adjustable by spring tension on the brake levers. To equalize the force that returns the left and right brake levers to their original position, use the adjusting bolts located at the base of the levers.
By twisting the bolt clockwise, we tighten the spring, unscrewing it. weaken it. By pressing and releasing the brake, we check the uniformity of the removal of the pads from the rim. Tighten the bolts on the left and right sides until the pads move the same distance when the brake lever is released.
Adjusting the position of the brake lever and the tension of the cable
To bring the brake lever closer to the steering wheel (for example, so that you don’t have to stretch your fingers too much), tighten the bolt on the brake lever.
In this case, keep in mind that you should not bring the handle too close to the steering wheel. It should not touch the grip when fully clamped.
When the position of the brake lever is set, it remains to adjust the cable tension. The task is to bring the pads as close to the rim as possible, leaving a distance of 2-3 millimeters between the pad and the rim.
To do this, you can tighten the cable in two ways:
For a rough adjustment, if the cable is very weakly tensioned, and the pads are far from the rim: loosen the bolt fixing the cable in the brake lever, tighten the cable, tighten the bolt.
While loosening the bolt, hold the lever and cable so that the cable does not “run away” and do not have to re-thread it into the seat.
for fine tuning, we use the adjusting screw at the point where the shirt comes out with a cable from the brake lever.
To make the screw spin freely, loosen the lock nut by unscrewing it counterclockwise. Turning the screw clockwise, we release the cable tension (the pads move away from the rim), unscrewing it counterclockwise, we increase the tension (the pads are closer to the rim). When the pads are in the desired position, tighten the lock nut.
That’s all! Checking how everything works. If necessary, re-adjust the springs of the levers (item 3).
Both avid cyclists and novice amateurs have to deal with the need to replace the brake pads on bicycle transport. And practice shows that the more you pedal, the more often you should change the brake pads.
It is the bicycle brakes that are responsible for regulating the driving speed of a two-wheeled vehicle and, in particular, for slowing down the speed of movement, as well as stopping. They can be of several types:
- pedal (or drum);
- and roller.
The most common ones used in most modern bicycle models are disc brakes and rim brakes.
The operating principle of rim brakes is extremely simple. On the bicycle handlebar there is a brake lever, from which a special cable (or a hydraulic line is laid) is pulled to the brake pads located on both sides of the bicycle wheel rim. When the handle is pressed, the rim is compressed by the pads, after which the wheel rotation slows down and comes to naught.
There are two types of rim brakes, which in turn are subdivided into several subtypes:
- Mechanical brakes including:
- vector (V-brake or “vibrake”) with V-shaped attachment of the levers to the brake pads;
- tick-borne (“crabs”) with U-shaped levers;
- and cantilever (obsolete predecessors of V-brakes).
- Hydraulic brakes, in which the applied force is transmitted from the handle to the pads by the brake fluid through a specially laid hydraulic line.
Rim brakes have a number of obvious advantages over other types of bicycle brakes:
- Low loads on bushings and spokes.
- Less braking heat.
- Easy setup even in the field.
- Low weight of the actual brake.
- Not a high price at all.
Replacing rim brake pads on a bicycle
Over time, rim brake pads (like any other bike part) fail. And any self-respecting bike enthusiast, not to mention professionals, should be able to replace them. over, this is easy to do with v-brakes. The main thing is to do everything slowly, clearly observing the technological stages in the required sequence:
- Open the brake. bring its levers together and remove the iron tip of the “shirt” from the groove formed (the cable comes out of it).
- Remove old pads, remembering in which sequence the fasteners were used.
- Install new pads, sequentially collecting all fastening pads and washers.
It’s even easier when it comes to cartridge pads! Only the rubber gaskets should be replaced. remove the locking pin, remove the old one and put a new gasket, and then fix it with the same (or new) split pin.
Care must be taken when changing v-brake pads as they can be left or right (the markings are directly on the pads). Then they should never be confused.
In addition, it is not enough just to change the pads, you also need to adjust them. And before that, check the brake cable for wear or breakage. He must be absolutely intact and easily move around in a “shirt”. It is also necessary to check the shape of the wheels so that there are no “eights”.
The brake pads must be correctly pressed against the wheel rim. And the pressure can be adjusted (adjusted) with the shoe fasteners. It is not difficult to get the desired angle if you hold down the brake and loosen the nut on each of the pads.
The v-brake cartridge pads should be located strictly horizontally, touching their entire surface to the rim, but not touching the tire. And when the required position is reached, you should fix it with a shoe nut. Regarding conventional brake pads, the rear of the pads must first come into contact with the rim horizontally.
During the tuning process, you must also ensure that the brake levers come together equally. Position adjustment is possible with a Phillips spring tension screw. If the lever barely moves, then the screw should be tightened, and when the lever moves too easily, unscrew.
Instructions for setting up the V-brake system. in the video review :. Disc brakes
A bicycle disc brake is a combination of a steel disc (rotor) located on a hub with a caliper. a device that actually clamp the disc with the brake pads. From the brake lever on the handlebar, the force is transmitted to the brake by a cable (mechanical disc brake type) or through a hydraulic line (hydraulic disc brakes).
Bicycle disc brakes have their advantages too. They:
- less clogging when driving;
- can work without problems while driving on snow or mud;
- as smoothly as possible (in contrast to rims) adjust the braking force;
- do not react to slightly curved wheel geometry (small “eights” are not a hindrance for them);
- do not affect the wear of the rim;
- and do not require expensive maintenance.
Many bicycle disc brakes have only one moveable brake pad. The second is fixed statically relative to the frame structure. This greatly simplifies and reduces the cost of the caliper. But, however, as the cyclist wears out, he will have to tighten the brake pad, which is stationary.
Brake discs are standard sizes. These are 140, 160, 180, 185, 203 or 220 millimeters.
Replacing pads in disc bike brakes
There is a step-by-step guide to replacing worn-out disc brake pads:
- First you need to remove the caliper and clean it if necessary.
- Then remove the retaining ring or wiring so that the bolt does not unscrew.
- Remove the boot (twist-on or snap-on, depending on the model). And if the bolt is dirty, then it must also be cleaned.
- Remove old bicycle brake pads. Sometimes they can be easily removed, and in some models they need to be pryed off-tucked a little, freeing them from the L-shaped protruding grip.
- Install new (organic or semi-metallic) pads. They should slide along the rotor, and the spring should not break out of its place.
- Put the bolt, and then the caliper. To check, you must press the brake lever several times well. And make sure that the pads have settled correctly and correctly press the rotor.
Disc brake pads should be replaced if:
- decreased braking force;
- a brake “squeal” is heard;
- or an unpleasant grinding noise is heard when the brake lever is pressed.
It is not safe to ride a bicycle with worn disc brake pads. In addition, the rotor (the steel brake disc itself) may fail. And this will already require a serious bike repair.
You will see step-by-step instructions for replacing brake pads on a bicycle with disc brakes in this video review: