Purpose, malfunctions and repair of the VAZ 2101 clutch master cylinder

If we simplify the formulation of the actions performed by the clutch drive, it will sound like this - the transmission of torque from the motor to the corresponding gearbox shaft with the ability to disable and then softly engage after switching to the desired gear. Nowadays, designers have not yet come up with anything more effective for achieving this goal than a hydraulic clutch drive. The diagram and principle of operation of the described device is simple: a depressed pedal acts on the clutch cylinder rod, which, accordingly, using hydraulic fluid located in the tank through tubes, activates, through the working cylinder, the fork and the release bearing.

Failure of the clutch drive occurs for several reasons, one of which may be a faulty clutch master cylinder; in order to repair it, it is advisable to understand its structure, signs indicating the inoperability of the mechanism, methods of repair, and if repair is not possible, then how to make it replacement.

Clutch master cylinder VAZ 2101

Stable operation of the clutch master cylinder (MCC) has a direct impact on the functioning of the gearbox and its service life, as well as the smoothness of gear shifting. If the hydraulic drive breaks down, control of the gearbox becomes impossible, as does further operation of the vehicle.

What is it for?

The main function of the GCS is to briefly disconnect the power unit from the gearbox when changing gears. When you press the pedal, pressure is created in the system, which acts on the clutch fork rod. The latter drives the release bearing, controlling the clutch.

How it works

The main components of the node are:

• outer cuff;
• sealing collar;
• union;
• stock;
• return spring;
• frame;
• case for protection.

The GCS housing contains a return spring, cuffs, working and floating pistons

Principle of operation

The hydraulic clutch consists of two cylinders - the main and the working (GC and RC). The operating principle of the hydraulic drive is based on the following:

1. Liquid enters the GC through a hose from the tank.
2. When the clutch pedal is acted upon, the force is transmitted to the rod by a pusher.
3. The piston in the main center moves out, which leads to the valve closing and compression of the liquid.
4. After the fluid is compressed in the cylinder, it enters the hydraulic system through a fitting and is supplied to the DC.
5. The slave cylinder drives the fork, which moves the clutch with the release bearing forward.
6. The bearing presses on the friction spring of the pressure plate, releasing the driven disk, after which the clutch disengages.
7. After the pedal is released, the cylinder piston returns to its original position under the influence of the spring.

The pedal moves the pusher, which, in turn, moves the piston and creates pressure in the hydraulic drive system

Where is

The GCS on the VAZ 2101 is installed under the hood near the vacuum brake booster and the master cylinder of the brake system. There are also reservoirs near the clutch cylinder: one for the braking system, the other for the hydraulic clutch.

The GCS on the VAZ 2101 is located in the engine compartment near the vacuum brake booster and the master cylinder of the brake system

When is replacement needed?

The cylinder elements wear out over time, which leads to interruptions in the operation of the mechanism. Repair or replacement of the main circulation system is necessary when the following symptoms appear:

• airiness of the system;
• leakage of working fluid;
• wear of cylinder components.

The presence of air in the hydraulic drive system disrupts the performance of the system, making its operation impossible. Air can enter the hydraulic drive through microcracks in the sealing elements of the cylinder or in the connecting hoses. If, when checking the system, a constant lack of fluid in the expansion tank is discovered, you need to inspect the entire clutch mechanism, since fluid can leave not only the master cylinder. If the amount of fluid in the hydraulic drive system is insufficient, the required pressure to move the clutch fork will not be able to be generated. This problem will manifest itself in the inability to separate the engine and gearbox when pressing the clutch pedal. If the leak is caused by wear of the connecting hoses, then replacing them does not raise any special issues. If the problem is related to the GCS itself, then the product will have to be dismantled, disassembled and the cause found out, or simply replaced with a new part.

Partial renovation

Repairing the clutch master cylinder using a repair kit

The first signs of a malfunction should serve as a reason to diagnose the clutch master cylinder and the entire system as a whole. Timely measures taken will allow you to avoid replacing the entire assembly by eliminating the malfunction by replacing worn parts. Repair of the clutch master cylinder is carried out using a repair kit, which includes the following parts:

1. Protective cap.
2. Retaining ring.
3. Piston.
4. Return spring.
5. Piston cuffs.

Cylinder repair work with installation of a repair kit is carried out in the following order:

1. Removing and disassembling the cylinder.
2. Flushing with brake fluid (other solvents are prohibited).
3. Inspect the cylinder for scoring, condition of the mirror and rod. Minor corrosion and scuffing can be removed with fine-grained sandpaper. Although damage of this type indicates a violation of the gap between the cylinder and the piston.
4. Replacement of worn parts provided in the repair kit.
5. Before assembling the cylinder, all parts are lubricated with brake fluid, and grease is applied to the spherical surface of the piston in contact with the pusher.
6. Assembly and installation of the clutch master cylinder.
7. Bleeding the system.

Which one is better to put

On the VAZ 2101 it is necessary to install a hydraulic clutch designed for the VAZ 2101–07. Cylinders designed to work in UAZ, GAZ and AZLK vehicles are not suitable for installation on a “penny” car. The situation is similar with imported analogues. It will be quite problematic to introduce a GVC from any foreign car, which is due to different mounting of the unit, different threads and tube configuration. However, a hydraulic drive from a VAZ 2121 or from a Niva-Chevrolet is suitable for the “classic”.

Manufacturer's choice

Today there are many companies that manufacture clutch master cylinders. However, when choosing and purchasing the unit in question, preference should be given to the following manufacturers:

• JSC AvtoVAZ;
• Brick LLC;
• Kedr LLC;
• Fenox;
• ATE;
• TRIALLI.

When choosing GVCs, it is better to give preference to well-known manufacturers

The average cost of a hydraulic clutch is 500–800 rubles. However, there are products that cost about 1,700 rubles, for example, cylinders from ATE.

Table: comparison of hydraulic clutch actuators from different manufacturers by price and reviews

Specifications

In the specifications for the master cylinder, manufacturers indicate the following parameters:

• side of the steering wheel (left, right) – important for asymmetric mounting;
• Is there a tank included (GCS can be sold with or without a tank);
• connection method (left, top, etc.) – help with selection if non-standard parts are installed in the hydraulic drive;
• body material: cast iron, aluminum, steel, polymer;
• dimensions of the body and structural elements (nozzle diameter, rod length).

These characteristics can be taken into account as auxiliary information when selecting a master cylinder for your car. Car enthusiasts pay special attention to manufacturing materials: the most common today are cast iron and aluminum, and there are also quite a few offers of cylinders with polymer bodies. Steel cases are quite rare, since steel combines high price and difficulty in processing.

Bleeding the clutch

In order to eliminate the possibility of failure of the clutch mechanism, the hydraulic drive system must be pumped after the repair is completed. To carry out the procedure, the car must be placed on an overpass or inspection hole, and the following must be prepared:

• brake fluid;
• wrenches for loosening brake pipes;
• rubber tube of suitable diameter;
• transparent container.

What kind of liquid to fill

For classic Zhiguli cars, the factory recommends using RosDot 4 brake fluid in the hydraulic clutch system. A 0.5 liter container will be sufficient for repairs. The need to fill the fluid may arise not only during repair work, but also when replacing the fluid itself, since over time it loses its properties.

It is recommended to fill the clutch system of classic Zhiguli cars with RosDot 4 brake fluid.

How to bleed the clutch

It is better to do the work with an assistant. The liquid level in the tank should be below the neck. We perform the following steps:

1. We pull one end of the hose onto the fitting of the clutch slave cylinder, and lower the other into the container.
2. An assistant presses the clutch pedal several times until it becomes tight and holds it down.

   
   An assistant in the cabin presses the clutch pedal several times and holds it pressed.

3. We unscrew the fitting and drain the liquid with air into the container, after which we tighten the fitting.

   
   To bleed the hydraulic drive system, you need to unscrew the fitting and release the liquid with air bubbles

4. We repeat the procedure several times until the air is completely removed from the system.

Video: bleeding the clutch on classic Zhiguli cars

During the pumping process, fluid will leave the clutch reservoir, so its level must be monitored and topped up as necessary.

When bleeding the clutch, you need to monitor the fluid level in the reservoir and top it up in a timely manner.

To bleed the clutch or brake system, I use a transparent tube, which allows me to visually assess whether there is air in the fluid or not. There are situations when you need to bleed the clutch, but there is no assistant. Then I unscrew the fitting on the clutch slave cylinder, unscrew the reservoir cap and throw a clean cloth, for example, a handkerchief, over its neck, create pressure with my mouth, i.e. I simply blow into the reservoir. I blow it several times to bleed the system and completely remove air from it. I can recommend another fairly simple pumping method, in which the liquid passes through the system by gravity, for which it is enough to unscrew the fitting on the working cylinder and control the liquid level in the tank. When the air is completely released, tighten the fitting.

Failures of the VAZ 2101 clutch master cylinder are a rare occurrence. If problems do arise, they are associated with damage to the boot or the use of low-quality fluid. If the mechanism malfunctions, you can restore functionality on your own. To carry out repair work, you need to prepare the necessary tools and read the step-by-step instructions, which will eliminate possible mistakes.

General product design

The clutch master cylinder is in most cases made of cast iron, inside which there is a piston and a pusher, which are the main working elements of the cylinder. Its pusher is connected to the pedal on one side and rests against the piston on the other. The main parts of the master cylinder are as follows:

1. Cylinder body.
2. A pusher connecting the pedal to the mechanism.
3. Piston.
4. Return spring and plugs.

The cylinder itself is divided by a partition into two parts: the upper one is used to fill the cavity with liquid from the tank, and the lower one is used as a working area.

Adjustment

The final stage of returning the system to working capacity is the adjustment of the mechanism. To adjust the unit, it is necessary to ensure the full stroke of the pusher, which is approximately twenty-five millimeters. By pressing the pedal all the way, the clutch performance is measured. A proper indicator indicates that the repair work has been carried out correctly. If the indicator is below the norm of 25, you should first check the presence of hydraulic fluid and the condition of the air systems.

The occurrence of any malfunction of the CCGT is the reason for urgent repairs. Different Kamaz models may have slightly different structure and functionality of the PSU system. The simplest mechanisms are those installed on the 5320, the most popular type of tractor-semi-trailer among the Russian truck industry.

A few words about hydraulic fluid

The hydraulic clutch usually uses brake fluid that has a set of characteristics that are optimally suited for the given task. For the operation of the system, what is primarily important is a sufficient fluid level, which can be determined by looking at the reservoir on the master cylinder. If for some reason there is less brake fluid, top it up without waiting for problems to appear.

When working, you need to remember that brake fluid is quite aggressive to plastic, fabric, paintwork and even leather. So you need to work with it carefully, and immediately wipe off any drips or drops on parts or the car body with a clean napkin. For the same reason, you need to monitor the condition of rubber parts that come into contact with the brake fluid: they can deteriorate very quickly and literally dry out under the influence of aggressive chemicals for which they are not intended.

And, of course, you need to add brake fluid to the system in a clean, closed room (garage or auto repair shop) so that dust does not get inside.

An interesting property of brake fluid is its very good penetrating effect, due to which it seeps out through microscratches on the cylinder surface or piston, even if the rubber seals are replaced. For this reason, the repair kit includes a new piston, and scratches and abrasions inside the cylinder become a clear indication for replacing the entire part.

Signs of a GCS malfunction

When problems begin with the master cylinder, it most often manifests itself as a hydraulic fluid leak. When the clutch pedal begins to work poorly, the first stage of diagnosis will be a visual inspection: any leaks on the cylinder and even just slightly moistened seals are a sign of a problem that needs to be solved.

Basically, when there are problems with the cylinder, the clutch pedal begins to sink or move slowly, and the pedal “sticks” in the lower position.

Another problem with the GCS is clogging of the holes in the tank lid. For normal operation, the level in the cylinder reservoir must rise and fall freely, and for this purpose, ventilation holes are provided in the cover. If they become clogged with dirt, the hydraulic drive begins to work with difficulty: the pedal becomes stiffer and does not return well to its original position.

How to adjust pedal free play on Nissan cars

As the clutch parts (disc and basket) wear out, the free play changes, and therefore requires adjustment. On a Nissan car, the clutch drive can be different - mechanical and hydraulic, so the PS adjustment is carried out differently. For example, a cable is installed on Nissan Sunny cars in bodies N13 and N14, Almera, Primera; Qashqai, Tiida, Almera Classic, Note, Maxima cars are equipped with a hydraulic drive.

However, a hydraulic drive can also be installed on Sunny or Primera, much depends on the type of engine and model generation. Nissan “hydraulics” are usually equipped with cars with more powerful internal combustion engines (2.0/ 2.5/ 3.0 l); cars with 1.4/ 1.5/ 1.6 l engines come with a clutch cable.

On a Nissan N14 car, the cable is adjusted in the area of ​​the clutch fork; the adjustment mechanism is located at the very end of the cable.

The same cable is installed on the Almera, and in order to shorten it when the DS linings are worn out, car owners add washers, and in this case it is no longer secured with a lock nut.

Like on a Hyundai car, the GCS on Nissans is located next to the pedal; these parts are connected to each other by a rod on which there is an adjustment.

To adjust the free play of the PS on the Nissan Almera N16 ( />