Bleeding hydraulic brakes
I’ll show you how to bleed hydraulic brakes using the Tektro Auriga Comp brakes as an example.
At first it may seem like a difficult process, but in reality it is not, you just need to prepare well 🙂 What will be useful to us for this? mineral oil with a viscosity of 10W. (50ml, if on front and back) I used 50ml Shimano oil on tap in ChilinGrilin for 100 rubles, but you can take others with the same viscosity. I had enough 12ml for the front brakes. If you change the oil for another, then do not forget to drain the old one completely. Do not forget that only mineral oil is poured into the Tektro and Shimano brakes, and in the rest of the DOT! Tubes (the diameter is such that it adheres well to the calliper fitting). The easiest way to get a drip kit is from a pharmacy. In January 2010 I took it for 6.50 rubles. Or 30-40cm flexible tubes with a diameter of about 2.5-3.5mm. syringe 5-12 ml. The larger it is, the more convenient it will be in the process, so as not to jump and collect the keys all the time (an asterisk T8, adjustable, but preferably an open-end 7, possibly a 7-end hex, 3 and 5 hex) a jar for draining. It is desirable to keep it clean and dry. If you bleed an empty brake, the piston plug oil can be reused. I used a bent piece of iron, did it for 30 minutes, if anyone needs it and suits, I can borrow it. Someone inserts 5 ruble coins, someone inserts batteries and much more rubbish, in general, improvisation of a newspaper and a rag is possible here.
We will need approximately such a set
Let’s start with preparation. We will spread the newspapers, we do not regret them, because if something goes wrong (let’s say a tube breaks off the fitting), then everything within a radius of a meter will be splattered, you can reach the ceiling, if pressure builds up, it will take a long time to get out.
We unscrew the calliper with a 5 hexagon, unscrew the pad screw with a 3 hexagon, remove the pads and the spring. This is in order not to flood them with oil and not damage them, some pump them without removing the cars, but this is fraught with damage to the rotor, the pads themselves and the crooked position of the pistons. We put a tube on the calliper fitting, insert a plug between the pistons.
Now we need to fix the brake lever in a horizontal position. I did this on the steering wheel itself, I just moved the handle to the other side and turned the tank up (I have it adjustable). I put the bike up against the wall and put up a couple of stools to keep it from falling. he stood perpendicular to the floor. We unscrew the cover of the expansion tank using a screwdriver with a nozzle. an asterisk T8. We do this carefully so that we do not have to repair the entire handle later. After the first unscrewing, it is advised to replace the native screws with new ones for a “minus” screwdriver with the same length and M3 thread. This will allow you not to steam next time, that they may not get out.
We return to the calliper and the straw. We lower the other end into a jar or make a special bottle for this (a bottle, into the cork of which we insert the end of the tube and make another hole to let air out of the bottle). In general, it doesn’t matter where to drain, the main thing is not on the floor 🙂
After that, we unscrew the union, as I said, preferably with a 7 open-end wrench. I no longer had oil in the brakes (I had them after repair), it was not scary to unscrew it with a socket wrench, removing the tube from the fitting. If you have oil in the system and you cannot turn it off with an open-end wrench, then before that you should screw the tank down (otherwise you will have an oily fountain from the tank), lift the calliper above the tank, gently unscrew the fitting slightly with a socket wrench, put on the tube and put the jar under the other end. after which you can lower the calliper down and unscrew the expansion tank cap again;)
If you need to pour out all the oil from the brakes, then you need to lower the calliper as low as possible and turn so that both holes with a hydraulic line and a tube on the fitting are as low as possible. This will help drain the old oil out of the piston system completely. We pump it out by pressing the brake lever until the oil stops coming out and only air comes out.
Then we put the oil into the syringe (if you have oil in some tall and narrow jar, you can put an extra 10 cm of tubes on the syringe for the convenience of drawing oil). We transfer the calliper to a standing position (so that the fitting is perpendicular to the floor). We fill the entire expansion tank with oil from a syringe.
How to quickly bleed the brakes without using up all the oil and nerves?
We press the brake lever and hold it in the clamped position until it stops. 2. Clamp the tube extending from the fitting. (You can do this with your fingers, or you can leave the IV clip on). 3. Let go of the brake handle. We see how atmospheric pressure pumps oil from the reservoir into the system. 4. Unclench the tube extending from the fitting. 5. Add oil to the tank. (it is possible not every time, but after every second repetition of 1-4 points, the main thing is to prevent the tank from emptying, which will lead to air ingress and we will have to do everything from the beginning again).
The oil is quite liquid, if you don’t do this, you can pump the brake for a very, very long time 🙂
We repeat these actions, tapping the hydraulic line so that all the air goes out as quickly as possible. With such simple actions, we pump oil into the hydraulic line until clean new oil comes out of the fitting without large air bubbles.
When we see that the bubbles are no longer coming, we clamp the tube and tighten the fitting (the main thing is not to be too zealous here, because the calliper is fragile). Then we can remove the tube from the fitting and put on the cap.
Next, it remains for us to fill the tank with oil, you can do this not to the brim, leave 1mm to the edge, insert the rubber gasket, close the lid and tighten the screws.
After that, it remains for us to pull out the piston plug, wipe everything from the remaining oil (it is better to wash and dry it), return the pads to their place, hang and adjust. The main thing until the moment everything returns to its place, it is better not to press the brake lever, so as not to forcefully return the pistons back. If, for some reason, they nevertheless pressed, then you can dilute with an ordinary knife or flat screwdriver, inserting between them and slightly turning.
Bicycle disc brakes
Disc brakes are designed to brake a bicycle by converting kinetic energy into thermal energy by rubbing the pads against the brake disc. As mentioned earlier, bicycle disc brakes are mechanical and hydraulic. Their principle of operation is the same, but there are slight differences in design.
Disc Mechanical Bicycle Brakes
Disc mechanics is the following design.
- Brake handle. Mounted on the handlebars (attached with a clamp) of the bicycle and is designed to transfer the force of pressing the hand to the brake pads.
- Cable adjuster with lock nut. The cable adjuster is designed to change the tension force of the cable of mechanical disc brakes. Locknut. for fixing the regulator.
- Brake lever adjuster. Allows you to adjust the distance from the brake lever to the handlebars, thereby making it possible to set a comfortable position directly under the length of the cyclist’s fingers.
- Cable shirt. Serves to protect the cable from damage and dirt.
- Cable. Required to transmit the movement of the brake lever to the brake caliper.
- Cable holder. The place where the cable is attached and clamped with a fixing bolt.
- Caliper. A mechanism that activates the brake pads when the cable is pulled.
- Brake pads. They are metal platforms with an organic or metallized substance applied to them. Inserted into the caliper.
- Adapter. Serves as a kind of layer between the caliper and the bike frame.
- Rotor (brake disc). Mounted on the wheel hub.
Check the condition of the brake line for leaks
This item is exclusively for hydraulics. Before adjusting the hydraulic disc brakes of the bicycle, inspect the brake hose for damage (it is advisable to replace it, even if the damage is minor), and also check that there are no oil / brake fluid leaks at the joints of the hydraulic line with the caliper and the master cylinder. Another place where the brake fluid can poison is the rod going from the brake lever to the piston (if the cuffs are leaky). Well, after removing the brake pads, check the absence of leaks on the caliper.
Remove dirt and oil from brake pads and rotor
During cycling, over time, dirt and oil accumulate on the rotor and brake pads, which impair the braking performance of disc mechanics or hydraulics. Therefore, before adjusting the disc brakes, remove it from these surfaces. For this, you can use fine sandpaper. Remove the rotor from the wheel and clean the surface on both sides in a circular motion. We perform the same operation with pads (of course, on the one hand). Do not be too zealous, it is enough to remove a thin layer. After you have completed this procedure, try not to touch the pads and rotor with your hands or oily objects.
How to adjust hydraulic disc brakes
Although hydraulic brakes are called self-adjusting brakes, it is sometimes possible to notice a rustle or squeak that they emit during the braking process. In this case, adjust the disc hydraulics of the bike. Also, a similar procedure is necessary on a new bike if the brakes were set incorrectly from the factory.
- Slightly unscrew the bolts that fix the caliper to the adapter.
- We clamp the brake lever and fix it with electrical tape, rope or other improvised material.
- We make sure that the rotor is clearly in the middle of the caliper slot, and the brake pads are extended equally on both sides. If this is not the case, then you can set its position by slightly pressing on the rotor from the desired side. Due to pressure, the brake fluid will be evenly redistributed between the pistons.
- After that, we tighten the mounting bolts and remove the electrical tape from the brake lever.
After you have adjusted the hydraulic disc brakes, turn the wheel and check for friction. If you observe intermittent shuffling, then this is a signal that your rotor is slightly bent. To eliminate this malfunction, it is necessary to determine the place of friction, and on which side of the pads the rotor clings. Then rotate the rubbing area 180 degrees from the caliper and gently push in the opposite direction. This should be done very carefully in several passes, with each of which add force until friction completely disappears.
Setting up hydraulic disc brakes is shown in the video below.
First of all, you need to prepare the tools, place the bike vertically and secure it in special supports-racks.
Second phase. Adjusting the brake pads
What needs to be ensured when adjusting the brake pads? Their high-quality fit to the rim. This requires the correct setting of their position relative to the rim and setting the clearance in the inoperative position. The distance between the shoe and the rim must be 1 mm. But! If you have soft pads installed, the distance between the front and rear of the pads relative to the rim should differ by 1-1.5 mm. To set the correct clearance in such a case, a wedge-spacer must be used.
- First, we release the pad fastening nut so that it becomes movable.
- We install a wedge-spacer between the shoe and the rim if you have soft-type pads, if the pads are with a metal base, then we place them parallel to the rim.
- Rotate the pads so that they are parallel to the top of the tire. They must not protrude beyond the rim or touch the tire.
- Using washers, we fix the position and clamp the fastening nut.
This stage is completed. go to the next.
First stage. Adjusting the position of the brake levers on the steering wheel
Oddly enough, the first thing that needs to be adjusted is the position of the brake lever on the steering wheel. Further adjustment of the entire brake system will depend on its position. To do this, loosen the handle securing screw for a few turns and set it to a comfortable position. the brake lever should be pressed by the second phalanges of the fingers. Adjust the main position (distance to the handle) of the brake lever to a position convenient for you using the adjustment screw.
Types of brakes and the need to adjust them
Brakes are the main accessories for a bicycle and they are divided into two types depending on their effect. The first and most common type is rim, the principle of their operation is a mechanical effect on the wheel rim to reduce speed and rotation and stop. The second, not the most common type, is disk. Depending on the type of force transmission from the brake lever to the brake mechanism, the brakes are divided into mechanical and hydraulic. The following are guidelines for adjusting mechanical brakes.
The need for adjustment and adjustment
The brake is the main means of preventing accidents while driving, their reliability and correct adjustment ensure the safety of the vehicle and the passenger.
Tools and consumables
Bleeding hydraulic brakes is carried out in different ways, but there is the simplest one. For this process you will need:
- Transparent tube.
- 2 syringes. it is better to choose a volume of 200 ml.
- Allen key for loosening the bolt.
- Oil or brake fluid, depending on the system model. Shimano uses a special mineral oil.
- A rag for removing dirt that has appeared during operation.
The choice of brake fluid depends on the type of hydraulics. It is categorically impossible to fill in an unsuitable composition or mix different ones, this will lead to damage to the brake.
How to adjust everything yourself
It may be necessary to adjust the hydraulic brakes if you notice extraneous sounds while driving. creaking or rustling. A simple test will help to make sure that the adjustment is necessary: lift the wheel of the bicycle 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 performance of the brake. 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.
How to Adjust Tektro Brakes REACH Adjustment on all E-Bikes even Juiced BikesJUNK Scorpion BIKES
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 to make the stroke of the pads too small.
Replacing the brake pads
Poor operation of hydraulic disc brakes may 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 deal with.
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, the 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 move 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 wheel hub axle. Remember the location of the return spring between the pads. it releases them after the end of braking.
Thoroughly clean the surface of the valves 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 bike service, the brake system is repaired last.
Setting up hydraulic brakes on a bike
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 nuance should be taken into account. if the hydraulic system is closed, then you will have to adjust the pads manually. for this, special valves are provided.
- If you have to adjust disc mechanical brakes, 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 is easy to make a mistake.
After carrying out the work, be sure to check the operation of the brake system in action. ride your bike for a few meters and try to brake. If the cable was overtightened, 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 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 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.
Take the survey
Construction cylinders vary in size. Those that are installed in the handle are smaller than the workers acting on the pads. Thanks to this feature, the cyclist does not need to spend a lot of effort pressing the handle.
Hydraulic brakes are prized for the following benefits:
- quick response of the system in response to the squeeze of the handle;
- braking force is regulated by pressing force;
- hydraulics are several times more reliable than mechanical brakes;
- endurance of the mechanism, proven over the years.
- high cost compared to mechanical brakes;
- complex maintenance. the repair of equipment implies accurate knowledge of the design device, as well as the skills for disassembling and then installing hydraulic brakes on a bicycle.
It is necessary to carefully monitor the condition of the brake hoses, they are very vulnerable. Their functionality may be reduced due to poor quality brake fluid.
Choosing the right hydraulic brakes for your bike requires you to be guided by your riding style. According to the number of pistons in the master cylinder, they are divided into one, two and multi-piston. Hydraulic brakes are available with disc and rim brakes. Most often they are installed together. For the operation of the mechanism, a special liquid or oil is used. The best brakes come from Shimano.
Despite the advantages of the system and the absence of the need for frequent maintenance of hydraulics on a bicycle, this structure is not protected from damage. There are several ways to identify a system failure:
- the brake handle is loose or becomes less elastic. when pressed, proper braking does not occur;
- the brakes work by themselves. spontaneous deceleration of the bike while driving.
In the first case, the cause may be o-rings that have become unusable. Then they need to be replaced. In the second case, it is possible that air has entered the hydraulics on the bicycle, due to which there is pressure on the brake fluid and the brakes are applied. This can happen for various reasons: the bike falls, the amount of oil, liquid is not enough, the circuit is open. Water ingress can also cause failure of the main piston. If the hose has been damaged, install a new one.
If malfunctions of the brake system are found, then it is time to pump fluid in it.
Hydraulic brake device
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.
Setting and adjusting brakes on a bicycle. disc and rim, mechanical and hydraulic.
Before moving on to the main question of how to adjust the brakes on a bicycle, we will single out several types of them: disc, hydraulic, rim. Thanks to the large assortment on the market, every cyclist will be able to choose exactly what they like best. Any of the options presented equally fulfill the tasks assigned to them, namely, knocking down high speed. The difference between them is only in the contact surface. If discs are bought for damping high speeds, then for other types they buy brakes that are in direct contact with the rim itself. These braking elements can be of different sizes, on which the contact area itself depends. As a rule, the larger it is, the better the wheel speed reduction is achieved.
Hydraulic Disc Brake Installation and Setup
The main features of disc brakes:
Adjust disc brakes as follows:
- check whether the cable responsible for the operation of the disc brake is in place, because sometimes it may be out of place and this is the reason for a difficult ride;
- see if the wheel is correctly placed in the frame itself;
- tighten all the bolts securing the brake to the rear or front fork;
- check the tightening of the screws on the wheel hub;
- set up movable and static pads;
- we loosen the bolts holding the brake machine with pads;
- squeeze the brake handle (if you don’t have someone to help, then fix the handle on the handlebars with a rope);
- after that, the pads should fit under the disc;
- tighten the screws.
Adjusting mechanical disc brakes on a bicycle.
Disc brakes are becoming popular today, and the craze for them began about 4 years ago. The point is not at all about reliability, but about the fact that their presence on the bike gives the impression of a racing motorcycle or emphasizes the coolness of the owner of such a bike.
Adjusting and adjusting hydraulic brakes on a bicycle.
You can use a sheet of white paper to adjust the disc brakes. It requires you to put it behind the disc and this will make it possible to adjust the gap between the rubber main pad and the disc itself. As a tool, you can take 4 mm and 5 mm hexagons, a ruler, a Phillips screwdriver. We do all the initial steps, as indicated in the example with mechanical disc brakes, and turn the screws until you feel that they no longer lend themselves to clamping. On all bicycles using this braking system, the discs are slightly bent and friction will be heard while riding. This can be avoided with an adjustable wrench, that is, they need to slightly bend the base of the disc in order to achieve absolute evenness. But after riding the bike for a long time, they deform again. We check the location of the adapter itself and tighten the bolts again. If the machine itself is slightly offset to the side, then it is necessary to loosen them and substitute a white sheet of paper. We estimate the gap between the pads and the disc and tighten the bolts back.
How to bleed hydraulic brakes on a bicycle. video.
- pumping the disc brake system begins with untwisting the master cylinder, and after installing it in a horizontal position;
- remove the cover from the cylinder itself (in most cases, screws with cross-shaped grooves are used for fastening);
- we run the brake fluid on a mineral basis through the system;
- make sure there are no air balls;
- we install the device with liquid in the inlet nipple (exclude it from getting on the paint of the bicycle, as the composition may contain components that corrode it);
Adjusting and adjusting rim brakes v brake on a bicycle.
In the overwhelming majority of cases, v brake is installed on budget bicycles, walking and children’s bicycles. These are rim brakes with acceptable power and modulation. no wheel locks occur. Before starting work, you must provide yourself with the following tools: a 5 mm and 3 mm hexagon, a screwdriver, and pliers.
How to adjust hydraulic disc brakes (bicycles)
- unfasten the brakes themselves;
- the main requirement is to put the wheel in a level position;
- return everything to its original position;
- tighten the cable with a hexagon and pliers;
- if the handle stroke is large, then it is required to tighten the cable even more and strengthen the brakes themselves;
- check the speed of the wheel. the course must be free. It happens when thorns are heard, then in this case it is worth adjusting the spokes themselves;
- if one brake surface v brake is closer to the rim than the other, take a screwdriver and loosen or tighten the forcing shoe screws.
Above, brief instructions were presented for those who like to consolidate their knowledge not only with the help of video, but also in text format. Bicycle brakes, types, settings. are present in this article. Each brake system is accompanied by an introductory instruction, especially complex types. the hydraulic version. For them, there are restrictions in the selection of fluid and if you do not follow the advice, then neglect and pouring anything in will lead to injury and nervous stress. If you do not want to visit a traumatologist, follow the rules. Any type of brake will wear out over time and must be replaced. Practice shows that disk modifications are less vulnerable, which can last a long time. If they are incorrectly adjusted, the clamping index between the front and rear brakes will be different. Some will say that the reason is in the length of the cable, since the front part is half the length of the back. If the cable is not completely closed, then try to lubricate it. The fact is that inside the rubber hose there is a steel tube, which is responsible for the smooth and free sliding of the cable. Over time, it rusts, and this leads to ruptures and unweaving, and in order to avoid such a nuance, it is advisable to apply a few drops of machine oil or grease to it.