BIKE HYDRAULIC BRAKES, BLEEDING THEM
Hydraulic bike brakes 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.
BIKE HYDRAULIC 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 are using 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 stop performing their functions altogether.
Because the hydraulic braking system makes the cyclist feel the brake better and the brake lever responds more clearly, hydraulics are often fitted to high-performance 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 the repair. For example, if you pierced the hydraulic system somewhere far outside the city, then this is a significant problem, the elimination of which is very, very problematic.
Mountain Bike Maintenance: How to fix spongy disc brakes
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 carried out 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 driving. Consider a shimano brake system. To pump it, use a special tool attached to the body of the main cylinder. 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 escaping the body of the machine. It is necessary 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, slowly, we can carry out 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 cleaned 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 necessary. 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.
PRO TIP: Get Your Brake Levers Super Dialed! / Mechanic Mondays. EP2
Wash your hands before installing pads in the hydraulic brake system. You have been pumping the brake system and your hands, for sure, are in the remains of brake fluid. You don’t want to get the pads dirty when installing 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 want to note that if the speed of the bike is high enough, then you need to use the hydraulic brakes very carefully.
If we consider the hydraulic brake drive, then it is appropriate to note the possibility of using oil or a special fluid. Each of the options has both disadvantages and advantages, but so far there is no unequivocal opinion on this matter. The caliper can be monolithic, due to which the structure becomes light and rigid, and composite, characterized by a lower price, but more complexity in terms of maintenance.
The hydraulic disc brake is reliable but difficult to repair in the field. True, it fails in extremely rare cases. There are a number of problems associated with the fact that disc hydraulics have a very small gap between the pads, and in the presence of heavy dirt, they wear out much faster. However, in this case, the mechanics cannot boast of at least some advantage, since damaged pads cannot be adjusted on the go, and in the case of hydraulics, this is done automatically during wear.
Disc brakes are much more expensive than rim brakes, their load on the hub during braking is greatly increased, although this issue can be called controversial. It is not necessary to delve into this topic in more detail, it is better to talk about the manufacturers on the market of hydraulic brakes.
Troubleshooting and repair
To understand what exactly happened to the bike’s braking system, several experiments are needed. The first step is to remove the wheel on which this problem is noted. Next, you will need to make some effort to clean the brake machine from dirt, which is easiest to do with a toothbrush. The main task in this case is to remove the pads.
After opening access to the working pistons, you must press them in with a screwdriver, and then gently press the brake lever. Both pistons should move forward. If one of them is jammed, then you need to use a repair kit to eliminate the existing malfunction. The piston system should be carefully inspected for various leaks. If they are present, we can talk about a strong wear of the cylinder group. Now you need to replace the pistons or special O-rings on them. Finally, the entire hydraulic line must be carefully inspected. A good sign is the absence of kinks, dents and other types of damage on it. If available, it is worth replacing the entire hydraulic line.
Next, you need to put a cambric on the pumping bolt, and then immerse it in a container to collect the remaining liquid. After that, you need to unscrew the cover of the expansion tank and fill it with liquid to the maximum level. You should press the brake hand several times, but it is recommended to do this smoothly and slowly. It is required to press until tightness appears. Next, while holding the handle, unscrew the bleed bolt together with the cambric and add fluid to the expansion tank. It is recommended to carry out such a procedure until the handle has acquired the required level of rigidity. After that, you can screw on the expansion tank, and then remove all tools. Everything is ready, now the brakes are fully pumped.
Types of hydraulic disc brakes
The difference between a disc brake and a rim brake is that braking is carried out by clamping the disc, which is fixed on the hub rather rigidly with special pads fixed at the rear on the frame and at the front on the fork stays. The master cylinder has a different design, so the hydraulic brake can be one of the following types: single-piston, double-piston with floating or opposed pistons, multi-piston. The third variety is mainly used. You can meet models belonging to the first type, but due to certain shortcomings, they were almost completely replaced by the second and third types. Sophisticated multi-piston systems are used for downhill where power is more critical than simplicity.
Why do you need pumping?
If you press the brake lever, and it goes to the grip, that is, its stroke is too great, but the pads do not move or do not reach the brake disc, then you can draw conclusions about the need for bleeding. A similar situation is observed if the lever is too easy to move when pressed or fails altogether. When the handle is pressed sharply, and after the system is triggered, it does not return to its original position, it is also required to pump the hydraulic brakes onto the bike.
In these cases, the reason for the failure of the system was the air that was inside. First of all, you need to find the place through which the passage is carried out. It should be noted that this may be preceded by damage to the hydraulic fittings, weakening of the pumping union on the cylinder, boiling of the liquid, which is associated with overheating. When the entire system has been checked for fluid leaks, you can begin to repair it.
If you need to bleed the hydraulic brake, physics in this case says you need to do it on a horizontal flat surface. The pads must be spread apart so that they do not reach the disc. Next, you need to unscrew the master cylinder, and then fix it horizontally. For each system, the pumping features may differ, so you should use the instructions, in which everything is detailed.
Principle of operation
To understand how a hydraulic brake works, it is necessary to consider its design. To fill the hydraulic line, a special oil or brake fluid under low pressure is used. Pressing a special handle displaces fluid from the hydraulic system, as a result of which it exerts pressure on the working cylinder mounted on the fork or bike frame. As a result, the brake pads and piston are activated, which leads to the wheel blocking.
It’s pretty simple. The hydraulic brake diagram provides a visual representation of the operation of the entire system described. Working with such a device requires understanding that brake fluid is extremely toxic, which often causes severe poisoning. In addition, it can have a detrimental effect on plastic parts and paintwork.
Although there are so many types of braking systems out there, hydraulic brakes are now quite common on mid-range bikes. With the growth of their popularity, a noticeable drop in can be noted. Therefore, it is quite possible that you decide to convert your bike to a hydraulic brake system. There are many examples of this, but we will give only a few.
One of the manufacturers is Shimano. Hydraulic brakes of this brand are presented in several lines. The most recent was Deore. Its characteristic is stable operation of the master cylinder, handles that are comfortable and pleasant to use. The cyclist can get real pleasure from how the whole system works well and behaves obediently. The picture is slightly overshadowed by the rattling of the brake lever itself. The new collection is presented in two rotor mounting options: bolted and pinned. One set contains two types of pads. metallized and rubberized. The wear of the latter proceeds as quickly as possible. All in all this is a superior quality hydraulic brake that is well worth the money you spent on it, namely 50.
CLIM 8 CLARK`S brakes are characterized by the fact that buying a device for the price of a single-cylinder brake, you get a full-fledged multi-cylinder device. However, everyone knows that miracles do not happen, so the design of the pens is a little alarming here, but this parameter also finds its fans. But the hydraulic hoses received metal and Kevlar reinforcement.
The most interesting six-cylinder design is found in the caliper. This system is characterized by such a disadvantage as an increase in mass. In addition, during the installation process, it is required to fit the pads to the discs as carefully as possible.
How to set up hydraulic brakes on a bike
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 push 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 engagement 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 have to be readjusted.
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, 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.
Checking the readiness of the system for adjustment
- 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 mounted 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.
How to check and adjust the brakes
There are clear instructions for checking and adjusting the brake system of a bicycle. If you stick 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. Honor has one caveat. if the brake lever touches the steering wheel, then you just need to pull the cable. The operability of the rear wheel brake system is checked in the same manner. To tighten 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 setting of the brake system for rim and disc type is different, since different rotating mechanisms and pads are used.
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 align the pads symmetrically with respect 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 such a 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 rolling block 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.
Advice. 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 a wing and the position of the fixed shoe (in order to maintain symmetry about the rotor).
For your information. Caliper centering can be skipped if this operation was performed earlier and the wheel was not removed.
How to pull
Proceed in the reverse order of loosening the cable and you will get the desired result.
Centering the caliper in relation to the disc
Now on to the big deal: how do you adjust the brakes on your bike for the first time? We want the disc to fit exactly in the caliper. To achieve this, washers are installed between it and the frame. They come in different thicknesses, so the installation is carried out by the selection method. This is a time-consuming process because tightening the bolts pushes the caliper much harder against the frame than simply pressing it down by hand. Having substituted the washer, you constantly need to tighten tightly and watch how the caliper is located in relation to the disc.
However, hydraulic brakes on a bike are much easier to adjust. For this, there are adapters that are located between the rear triangle of the frame and the caliper.
You must first screw the adapter, and the caliper is already there. However, the bolts should not be tightened yet, they should just fix everything. After that, you need to clamp the brake lever and watch how the pads clamp the disc. When he presses, the caliper will go to his workplace.
For greater reliability, it is worth twitching the wheel a little so that everything is fully in place, and tightening the bolts. When everything is fixed, you need to bleed the brakes. This is done by sharply pressing the handle 15-30 times. This is done to ensure that the pads are in the ideal braking position.
If the pistons extend the pads unevenly
If one piston does not work freely, it is most likely clogged. In this case, it is worth removing the wheel, and then removing the pads from the caliper. You will need a clean metal plate with holes for the mounting pins.
Using it, move the serviceable piston and press the brake lever so that the clogged one can get out. After that, it is necessary to wipe it with a clean cloth and apply mineral oil (non-aggressive to rubber) on its surface. Then put the piston back, wiping off excess oil. often the rear brakes on the bike get dirty, probably due to the fact that there are more mechanical parts and a drive.
If the disc is bent
If the disc is bent, how do you adjust the brakes on the bike? It needs to be aligned. This can be done with a special tool, or you can use an adjustable wrench. It is necessary to determine the curvature zone and install an adjustable wrench in its middle part, having previously placed a piece of cloth so as not to scratch the surface. After that. bend in the required direction.
How do I adjust the brakes on my bike? Rear brakes on a bike
If the hydraulic brakes on the bike were installed for a long time and began to work worse, then it’s time to adjust them. First, we install the disc on the wheel hub, you need all the bolts to be evenly and carefully tightened.
When the brakes are not pressed, the pads rub against the disc
It so happens that everything seems to be adjusted, ideally installed, and when checked, it shifts a little, after which the pads touch the disc. How do you adjust the brakes on the bike in this case? Determine which of the pads is rubbing. After that, we loosen the bolts on the adapter and move it towards the friction side. We also look to make the block parallel to the rotor. And so by the selection method we achieve the perfect result.
When both the left and right pads cling to the disc, you need to adjust the hex on the brake lever. It must be unscrewed until the pads fit properly. It is designed for just such an adjustment. After all the settings, it is worth checking again how everything works.
If you need to change the brakes
Now let’s look at what to do in the event that we change the brakes for a bicycle. To put them on, the hydraulic line must be disconnected, because it will need to be pulled through the mounts. If the brake hose is attached to the frame, you do not need to disconnect.
We will consider a more complex option and know exactly what to do in this case. Disconnect the brake hose and thread it through the mounts. But before doing all this, you need to disconnect the pads to keep them clean. After all, working with oil is dirty, and you can accidentally stain the pads and disc.
Disconnect the hydraulic hose and see the cam that is inserted into it and the compression fitting (it looks like a ring on top). The cam is designed to prevent the plastic hose from contracting when the system is very hot. And the fitting holds it in place.
To extend the hose, the end must be cut off along with the cam and fitting. The cut must be clean and even. To do this, it is better to use a special cutter, with which you can quickly and efficiently carry out everything. If there is no such tool, then you can use a blade or knife and cut it carefully on a flat surface.
When the pistons cannot return to their original position?
The pistons may not return due to clogging, then you need to do the procedure described above. It could also be the brake lever, or dirt can get into it. Then you will need to disassemble and clean it. A more serious problem is when the brake oil system has leaked. If the leak is not strong, then it is worth changing the gaskets at the joints. In case of more complex breakdowns, it may be necessary to replace the brakes.
It so happens that the brake lever falls through. This can occur when air is trapped in the hose. Bleeding the brakes will help fix this. However, this can also be due to a breakdown in the hydraulics. Depending on the place of leakage, you need to replace the gaskets, the worst option is to replace the hydraulic line.
Service technology: brake adjustment on MTB type bike
The level of safety, to a greater extent determined by the state of the braking system, depends not only on the class of components used, but also on the frequency of inspection and the frequency of adjusting the unit. Despite the complexity of its design, the service is quite affordable for anyone interested in cycling.
Pro: How to Set Up Hydraulic Disc Brakes on Your Bicycle
The adjustment of disc brakes with a hydraulic drive is much easier to implement, in contrast to a disc-type retarding module using a cable as a force-transmitting element. The setting takes place in the following sequence:
- loosen the screws securing the caliper to the bracket;
- clamp the brake lever;
- make attempts to turn the wheel back and forth, thus centering the position of the caliper;
- tighten the screws securing the brake machine;
- in cases where the cylinders / pistons were serviced or a new machine is installed, it is necessary to bring the pads to the rotor to the working condition by sharply pressing the module control knob 15-20 times.
During the operation, problems and questions may arise how to adjust the brakes on a bicycle with hydraulic lines, expressed in the following:
- when rotating, the rotor touches one of the pads. it is necessary to slightly shift the caliper towards the rubbing pad;
- when rotating, the rotor touches both pads. it is necessary to remove them from the disc by slightly unscrewing the adjusting hexagon on the brake lever (it also determines the moment the pads engage with the disc);
- when the handle is pressed, the pistons move out unevenly. it is necessary to remove the module, push the piston that moves out in a timely manner using a plate or a screwdriver and, fixing it, carefully push out the jammed piston, pressing the brake lever, and clean it;
- the pistons do not return to their original position. it is necessary to clean the entire system;
- the brake lever fails. it is necessary to bleed the system (if there are bubbles) or replace the brake line (if there are leaks).
Intermediate: Setting up mechanical (cable) disc brakes on a bicycle
Before adjusting any disc brakes, check:
- the accuracy of the wheel axle setting in the dropouts (seats) and the clamping force of the hub in the frame / fork;
- uniform tightening of the brake disc (rotor) and the brake unit housing;
- deviation of the rotor shape from the vertical plane (if necessary, align the rotor with an adjustable wrench).
The technology, including how to adjust mechanical disc brakes on a bicycle, is as follows:
- disconnect the drive cable from the brake machine (caliper);
- loosen the two screws securing the caliper to the brake unit housing;
- extend the fixed block (located closer to the wheel spokes) using a bolt located on the inside of the caliper;
- press the caliper so that the static pad is in contact with the rotor;
- tighten the screws securing the caliper to the body of the brake unit (attention. the plane of the shoe should not move from the plane of the rotor);
- by rotating the corresponding screw, achieve a minimum clearance between the fixed block and the rotor;
- rotating the lever to which the cable is attached, make sure that in the clamped position the rotor does not twist, but bends evenly towards the static block (in case of non-observance of the requirement, repeat the caliper adjustment);
- install and fix the cable.
After the adjustment of the working unit of the disc brakes, the setting torque should be adjusted by rotating the adjusting drums near the brake lever and caliper.
For your information. On a properly adjusted deceleration unit, the central vertical section of the brake rotor should lie in the same plane with the caliper slot.
Types of brakes and features of their adjustment
On mountain bicycles, three types of brake modules have been used:
- rim (V-Brake);
- disk with a mechanical drive;
- disc with hydraulic drive.
As is the case with the derailleurs, it is advisable that the adjustment of the cable brakes on the bicycle is preceded by a detailed inspection of the control line elements. the cable and shirt. Before adjusting hydraulic disc brakes, it is recommended to inspect the hydraulic line for various damage and, if necessary, replace it with subsequent bleeding of the system.
The adjustment of all brake systems in some cases is preceded by the adjustment of the control handle (using the adjusting screws located in the product body). The purpose of the operation is to find the optimal resistance force and a safe location relative to the rudder.
Setting up a budget system: how to properly adjust V-brakes on a bicycle
- using a hexagon, the screw securing the shoe to the lever is loosened;
- the block is tightly pressed against the rim;
- the search for the optimal location of the shoe is carried out. its outer and inner edges should be coradial to the wheel circumference;
- the block is slightly pulled against the lever.
Debugging the location of the working plane of the shoe.
When adjusting the lever brakes on a bicycle, this transition is given special attention: it is necessary to ensure that the front edge of the pads touches the rim before the rear. To do this, under the rear edge of the shoe, fit some solid object with a thickness of 1-1.5 mm and press it against the rim. Then the fixing nut is finally tightened. Next, repeat the transition for the second lever.
Centering the position of the levers (selection of the force of the springs of the levers)
The challenge is to ensure that the pads are in contact with the rim at the same time. Regulating elements. screws located on the left and right levers, near the place where the latter fit on the fork. The cycle of preparation for commissioning includes the following transitions:
- install the cable guide in the tube holder on the arm;
- if the cable was disconnected, it must be fixed with the corresponding screw on the lever.
Operations on how to adjust the force of the brake springs on a bicycle are as follows:
- clamping the brake lever, the moment of contact of the pads with the rim is monitored;
- on the lever with the block that touched earlier, it is necessary to strengthen the spring by tightening the corresponding screw (you can loosen the spring on the second lever).
Setting the distance of the stationary arrangement of the pads from the wheel rim (selection of the optimal cable tension)
The task of the stage is to adjust the severity of the brake mechanism. The operation is performed in the following sequence:
- the adjusting drum turns almost all the way (you can leave 2-3 threads);
- by unscrewing the screw securing the cable to the brake lever, slightly tightening it and tightening the fixing bolt again, the optimal distance between the pads and the rim is found (1-2 mm);
- if it is necessary to slightly increase / decrease the severity of braking, it is enough to unscrew / wrap the drum.
The last brake setting on your bike (point 4) depends a lot on the correct shape of the rim. In the presence of a small figure eight, it is necessary to find the optimal position in which the pads will not wipe the rim. When driving over bumps or holes at high speed, check this setting as often as possible.
The solution to the problem “how to adjust double-wishbone rim brakes on a bicycle” is to find the optimal position of the pads relative to the rim (coradiality and successive touching first of the front edge, then the rear), setting the simultaneous adherence to the rim.
When adjusting disc brakes with mechanical and hydraulic drives, it is necessary to make sure that the pads are equidistant from the rotor and are located in planes parallel to the disc. On cable-operated disc brakes, make sure that the disc bends evenly towards the static pad.
The final stage of setting up any brake system is to regulate the sharpness of the module (the location of the setting moment depending on the position of the control handle).