Useful Tips

Fluid replacement in the clutch hydraulic actuator is a guarantee of safety


Only special brake fluid is poured into the clutch release hydraulic drive system (TU MXP 1608-47, TU 35-KhP-430-62 or TU 35-KhK-482-64).

Do not mix brake fluids of different grades and add at least the smallest amount of mineral oils, glycerin, gasoline, kerosene or their mixtures, which cause swelling, and then complete destruction of the rubber parts and, as a result, the failure of the system. The use of ethylene glycol is also unacceptable due to the corrosion of metal parts caused by it.

In the absence of a special brake fluid, you can use a mixture of 50% (by weight) castor oil and 50% butyl alcohol. It is allowed to replace butyl alcohol with isobutyl or ethyl alcohol. It must be borne in mind that ethanol evaporates more easily than butyl alcohol, and the composition of the mixture will change (especially in hot weather).

When changing to a different type of working fluid, it is necessary to remove the previous one and thoroughly flush the entire clutch hydraulic drive system with alcohol or new brake fluid. Brake fluid is poured into the housing of the feed tank 3, without removing the strainer 2 from it, in order to avoid the ingress of impurities into the system. The brake fluid level should be 10-15 mm below the upper edge of the tank.

It must be remembered that the brake fluid leaves spots on the painted surface of the car body, so you need to fill the system carefully, avoiding the ingress of fluid on the body.

It is very simple to monitor the liquid level in the feed tank, as the tank is made of translucent plastic.

Fill the hydraulic clutch release system with brake fluid and remove air from it in the following order:

  1. Fill the tank with fluid through a strainer to a normal level. For faster filling of the tank, it is recommended to slightly raise the strainer.
  2. Remove dust and dirt from the air exhaust valve on the working cylinder and, removing the rubber protective cap 2 from the valve head, put a rubber hose (supplied with the car) on the valve head. Immerse the free end of the hose in brake fluid poured into a clean glass vessel with a capacity of at least 0.5 l, which should be filled to half its height.
  3. Sharply depress the clutch pedal with your foot 4-5 times in succession (with an interval between pressures of 1-2 sec), and then, leaving the pedal depressed, unscrew the air release valve by 1/2 to 1 turn. Under the pressure created in the system, part of the liquid and the air contained in it will escape through the hose into the vessel with the liquid (air from the hose will exit in the form of bubbles).
  4. After the fluid has stopped flowing out of the hose, screw the air exhaust valve to the full.
  5. Repeat steps 3 and 4 until the holes have completely ceased to release air from a hose immersed in a vessel with liquid (this will require up to 75-80 pedal pressures).

In the process of performing the operation of removing air from the hydraulic drive system, brake fluid is added to the feed tank, preventing the level in it from falling more than 2/3 of the normal value. Insufficient height of the liquid column above the bypass and compensation openings in the main cylinder body can lead to aspiration of atmospheric air into the cylinder (and into the system).

After the air bubbles exit the hose, keep the pedal depressed and tighten the air bleed valve until it stops and only then remove the hose from its head. Next, put a protective cap on the valve head, add liquid to the tank to a normal level and replace the tank cap.

After pumping is completed, wipe the surfaces of the parts of the hydraulic clutch with a cloth.

To completely fill the clutch hydraulic drive system, 150 g of brake fluid is required.

The brake fluid released into the vessel when pumping the system can only be used to refuel it after it has settled (for at least 24 hours) and air has completely been removed from it, then it must be filtered.

The quality of the system bleeding should be judged by the total stroke of the piston rod of the clutch slave cylinder when the clutch pedal is pressed all the way into the rubber floor mat.

With a fully pumped system, the stroke of the piston rod, as indicated above, must be at least 10 mm. With a smaller rod movement, if the system is operational and the full clutch pedal stroke is at least 150 mm, pumping should be continued, as mentioned above, until the air is completely removed from the system and a normal piston stroke is obtained.

Properly pumped clutch hydraulic system should ensure shock-free first gear in the gearbox.

If, when the clutch pedal is depressed, the first gear is shocked, make sure that the free end of the outer end of the clutch release fork is correctly set and the clutch mechanism is in good working order.

Why is brake fluid needed?

While depressing the brake pedal, the cylinder is compressed by filling it with fluid. She, in turn, is fed under high pressure to the caliper. As a result, the speed of the car drops, the movement slows down.

Often during maintenance, car owners may be told that it is necessary to replace the clutch brake fluid. You can do this yourself, which will allow you to save money on the services of service stations. The brake system must be checked at least twice a year.

The life of the brake fluid is for the most part strictly limited and regulated by the manufacturer. It is desirable to change it twice a year in the spring. During the replacement, it is advisable not to neglect banal safety rules.

Clutch Brake Fluid Requirements

Excluding the basic requirements - viscosity and boiling point - brake fluids must comply with some other:

No negative effect on rubber parts. Between the hydraulic pistons and the cylinders are rubber cuffs. The tightness of these compounds increases, provided that the rubber increases in volume under the influence of brake fluid by no more than 10%. After pouring the composition, such parts should not lose strength, ductility, deform.

Lubrication of friction pairs. The level of wear of pistons, surfaces of brake cylinders and lip seals depends on the lubricating properties of the composition.

Resistance to temperature changes. In the range from -40 ° C to + 100 ° C, the brake fluids of the clutch must maintain operational properties, not delaminate, and not settle on the nodes and parts.

The replacement of the composition should be carried out on average once every 2-4 years, and the frequency depends on the state of the brake system and the car as a whole. Simply put, the older the vehicle, the more often it is advisable to change the brake fluid. If the composition changes color before the deadline, then it is immediately changed.

We recommend to watch this video about the clutch pumping:

Brake fluid change

To replace the clutch composition of the car, you will need a second person, a key for 10 and several items:

A syringe or a rubber bulb.

Capacity in which the spent brake fluid from the clutch and hydraulic drive will merge.

A vinyl tube with a diameter of 4-5 mm can be taken from a dropper.

Fresh brake fluid. At least a liter and a half.

An overpass or inspection hole is not necessary, but desirable, as it greatly facilitates and simplifies the replacement process.

The brake fluid in the clutch and hydraulic drive of the car is replaced as follows:

With a key of 10, the spent auto-fluid merges from the system. The likelihood that air will enter the clutch or hydraulic actuator is high, so they are not completely emptied. Fresh liquid is poured into a special tank of the car to the level indicated on the body.

A new hose is attached to the bleeding hole, and a container is located at the bottom, into which the spent liquid will merge.

The second person must press the brake pedal several times until it fails, after which it is detained in this state. During this time, it is necessary to unscrew the bleed nipple and let out the liquid. After the pedal completely rests on the floor, the fitting returns to its place, and the brake is released.

The whole process is repeated at least ten times with each wheel until a fresh liquid begins to flow when draining. It is easy to distinguish it - in light color. The fitting is twisted, the tank is filled with fresh composition.

Pumping with other calipers is carried out according to a similar pattern in a certain order: first, right rear, then left rear, right front and left front caliper.

Fluid replacement video:

Possible malfunctions and deterioration of the clutch and brake system after replacing the TG

Modern types of brake compounds can be mixed, but there are strict limitations. This rule applies only to those auto-fluids that correspond to the same characteristics. However, it is worth considering the fact that products from different manufacturers can have not only a different formulation of manufacture, but also a different basis. For this reason, it is not necessary to allow mixing of fluids, since after replacing them, the brake system may fail.

Changing the shade is one of the main signs of the need to replace the composition. It does not indicate the presence of detergents, which is applicable to motor oils, but rather contamination with dust particles and wear products. If you do not change the clutch fluid in the hydraulic drive for a very long time, then irreversible changes can begin in it, for example, an increase in viscosity. All this can cause jamming of the brake cylinders, brake failure and clutch failure. Varnish deposits may appear on internal parts and components of the system. It is advisable to change the darkened liquid immediately, without waiting for the end of the operational period.

The fluid must be replaced not only in a timely manner, but also correctly. During pumping of the brake system, the old fluid is replaced with a new one without any admixture of air bubbles. For the implementation of this procedure, a volume of composition that is 1.5 times the volume of the tank is sufficient. If air has entered the system, the brake pedal will be activated from the second or third time. Pumping is carried out until the pedal becomes stiff and stops at the same point.

It is advisable to use brake fluid only that recommended by the car manufacturer. By purchasing this composition, it is necessary to accurately verify all specifications and characteristics.

The key to the durability and performance of the brake system is timely fluid replacement. If a used car is purchased, it is best to replace it immediately and pump the entire system according to the regulations established by the manufacturer.