How to check the starter bendix with your own hands in 15 minutes

Bendix starter

The starter bendix (real name is overrunning clutch ) is a part designed to transmit torque from the starter to the car engine, as well as to protect it from the high operating speeds at which the engine operates. The starter Bendix is ​​a reliable part, and it rarely breaks. As a rule, the cause of failure is natural wear and tear of its internal parts or springs. To identify malfunctions, let’s first understand the device and operating principle of the Bendix.

What is bendix on the starter and why is it needed?

The starter bendix is ​​a device whose operating principle is similar to the operation of the clutch installed in the transmission of a car with a manual gearbox. Unlike a more massive system, which serves to smoothly transfer torque from the crankshaft to the wheels, the overrunning clutch on the starter performs its function for an extremely short amount of time. In addition, disconnection from the driven gear, which is located on the crankshaft flywheel, must be carried out at the very beginning of the starter’s independent operation. These requirements determine the design features of the Bendix.

Not only the ability to start the car easily and quickly depends on the condition of the starter Bendix. Significant deviations in the operation of this part can lead to failure of the gears through which torque is transmitted to the crankshaft. Almost always, if one part fails, the parts mating to it will soon fail as well.

Originals, analogues, articles and prices

The first modifications of the Lada Kalina were equipped with a starting device with the catalog number “21120-3708010-00” (KZATE). It was fixed to the block wall with three nuts.

After the release of the Lada Kalina with a cable-controlled gearbox, the method of fixing the PU changed to a screw one.

Original indexes:

• 21120-3708010-00;
• 21901-3708023-00;
• 21120-3708045-00 (KATEK, KZATE, ZiT);
• 21901-3708051-00 (VALEO) (8 valves);
• 21902-3708056-00 (VALEO) (16 valves).

For automatic transmission type: Jatco – 21902-3708135-00.

The cost of PU varies depending on the modification. Base price from 3100 rubles. On models with a new type of fixation from 3400 – 3500 rubles.

Foreign analogues are no better in quality than domestic ones. The cost is 10 - 15% more expensive. Manufacturers: Blue Print, Bremi, Febi, Bilstein, Fenox, Glaser (see photo).

Where is the starter installed in a Lada Kalina car?

Many car enthusiasts wonder where the starter is located. As in many other brands, the PU is installed in the engine compartment, fixed at the end of the block on the flywheel side.

Bendix starter device

Bendix is ​​a compact part mounted on the starter shaft. This element is made of durable metal alloy. Parts have to work under increased mechanical loads, which explains the need to use wear-resistant materials.

The Bendix device is as follows:

• Leading and driven clips.
• Casing.
• Support cups.
• Pressure spring.
• Rollers.
• Roller springs.

The clips are mechanically connected to each other by rollers, which are pressed by springs and drive them into the narrow channels of the structure. Thanks to this feature, the clutch begins to work only when the engine starts. After spinning up the engine, the clutch immediately disengages as soon as the engine starts working on its own.

Bendix operating principle

The operating principle of the Bendix starter is based on inertial forces that force the position of the drive gear to change under different operating modes of the engine starting device. Thanks to the presence of this part, it is possible to reliably protect the electric motor, as well as the rotating elements of the engine, from “unauthorized” activation of this mechanism.

How does a Bendix starter work?

Bendix on the starter works as follows:

• At the moment when the ignition is turned on and the key is moved to the extreme position, electric current is supplied from the battery to the starter motor.
• The starter motor begins to rotate and sets in motion the shaft on which there are screw grooves along which the coupling moves under its own weight. As a result, the drive gear located on the bendix engages with the flywheel gear.
• After the engine starts, the Bendix gear begins to rotate quickly and move inside the starter housing.

The stability of the Bendix mechanism is also explained by the presence of a buffer spring, which significantly softens the moment of contact of the drive gear with the flywheel splines.

Signs of a faulty Bendix starter

The starter Bendix is ​​a very reliable part, but during prolonged use of the car this mechanism can also fail. Almost always, such an undesirable event is preceded by various manifestations that cannot be ignored. The most characteristic signs of a Bendix malfunction:

• Noise when starting the engine.
• The engine crankshaft does not rotate.

If the bendix is ​​not completely faulty, then a sign of improper operation of the part may appear periodically. Sometimes, this element engages with the driven gear, but after a short operation it slips off with a characteristic sound effect.

If there are signs of a Bendix malfunction, repairs should not be delayed for long. If the damaged part is not repaired or replaced in time, you will need to perform a more complex operation associated with installing a new flywheel gear, damage to which will not allow the vehicle to operate normally, even after purchasing and installing a new overrunning clutch.

Overrunning clutch repair

Is it possible to repair the Bendix starter with your own hands? Quicker! One of the “popular” methods is as follows. Completely immerse the removed starter in a suitable gasoline container. Leave for 5-6 hours (can be left overnight). Without removing the device from the container, the overrunning gear cleans the grooves better. Remove the snack and dry well. Sometimes this simple step helps. But if this does not happen, the device will have to be disassembled. After removing the bendix, inspect the fork that pushes it: if the part is worn out, you need to install another one. Check the play of the armature shaft - if there is play, you will not be able to reset the mechanism - you will have to buy a new one. If there are no “irregularities”, the Bendix is ​​repaired.

The procedure begins by disassembling the housing to get to the springs and rollers. They must be removed, cleaned, washed with gasoline and dried. Usually these parts do not wear out and do not require replacement, but still take a closer look at the rollers - if they have lost their cylindrical shape, you will have to look for normal ones (they need to be completely replaced).

However, in most cases the problem is rubber deposits inside the rocker arm that need to be removed. Also be sure to check the clutch housing for cracks. If so, replace the part. You also need to inspect the gear teeth - if they are worn out, you will need to look for a new one or change the entire transmission. Now take the bendix and check by holding it in a vice - the working device will rotate in one direction. Before installation, lubricate the restored mechanism with engine oil.

Possible causes of failure

The starter overrunning clutch consists of a small number of parts, so there can be several causes of breakdowns. The inner rollers wear out most often. Reducing the diameter of these parts makes it impossible to reliably engage the moving elements. Sometimes, flat surfaces can form on the rollers, which also interfere with the normal operation of the clutch.

All working surfaces that engage are subject to wear over time. Such malfunctions of the starter bendix are natural, but if they are present, the part cannot be restored.

How to check starter bendix

If the car engine does not start or the moment of starting is accompanied by unpleasant metallic sounds, then before deciding to repair or replace, you need to check the starter bendix. The initial stage of diagnosis may be based precisely on the auditory perception of the incorrect operation of this part. To use this method, you must be in close proximity to the engine, so it is recommended to involve an assistant in the event to soundly determine the quality of Bendix operation. If, when the engine starts, the starter electric motor is running, and a metallic grinding sound is heard from the location of this part, then, with a high probability, the overrunning clutch is faulty.

You should not rely only on your hearing organ when checking the Bendix. After detecting noise localized in the area where the starter is located, it is necessary to dismantle this part and carefully inspect it. The first action, which allows you to immediately determine the possibility of further use of the part, is turning the drive gear in different directions. If the moving element rotates in both directions, then the bendix will need to be changed. The presence of licked teeth also indicates the impossibility of further operation of the part. If there is play in the armature, as well as excessive wear on the fork, the Bendix will need to be replaced with a new part.

Bendix starter repair

The cost of a new Bendix, even for expensive car brands, is relatively low, but as an experiment, you can try to restore the part with your own hands. It should be noted that if there is excessive wear on the clips, the repair operation is almost impossible. It is impossible to increase the metal of these parts, but if only the rollers in the coupling have undergone a change in geometry, then the part can be repaired by replacing these elements with pieces of metal of suitable diameter. For this purpose, for example, pieces of drills of suitable diameter or fragments of nails of suitable size can be used. In the latter case, to increase the strength of the metal, it is recommended to harden it in such a way that the outer surface becomes more durable and the inside of the metal is not too brittle.

If the roller springs or pressure spring break, you can also select replacement parts of suitable stiffness and diameter. If there is another faulty part, it is possible to combine elements in such a way as to result in one serviceable bendix. The presence of several broken elements significantly increases the possibility of similar borrowings of well-preserved elements.

How to disassemble bendix

If you decide to repair the starter bendix, you will need to disassemble this part. This operation is performed as follows:

• Remove the starter from the vehicle. Before performing this operation, you should disconnect the battery terminals, unscrew the fasteners and disconnect the wires from the part.
• Unscrew the starter mounting bolts and disassemble the housing.
• Remove the solenoid relay.
• Disassemble the bendix.

In order to disassemble the bendix, it is necessary to remove the retaining ring, remove the washer and separate the outer and inner parts of the element. Before assembling the Bendix gears, they must be washed in acetone, dried and lubricated with temperature grease.

How to change bendix on the starter

Installing a new part to replace a worn one is much simpler and more correct. If you purchase an original spare part, then after the work is done correctly, the service life of the unit can be calculated in years. At the initial stage of repair, all operations are identical to repairing the unit yourself. You will also need to carefully remove the starter, disassemble it and disconnect the bendix. It is not necessary to disassemble the part; immediately after dismantling work is completed, you can proceed directly to installing a new bendix.

Replacing the starter bendix

After the old part is removed, work on installing a new bendix is ​​carried out in the following sequence:

• Lubricate the shaft with thermal grease.
• Install the part onto the shaft.
• Place the washer and retaining ring on the shaft.

Difficulties in installing the bendix can often be observed when installing the retaining ring. This piece can be placed in place using open-end wrenches or sliding pliers. When performing this operation, care should be taken, because the elastic element can spring back a considerable distance.

After the new bendix is ​​installed and the starter is assembled, it is recommended to check the operation of the part without installing it on the engine. For this purpose, you can use a car battery and “lighting” wires. It is important to maintain correct polarity when connecting the contacts, otherwise the motor will start to rotate in the opposite direction. To avoid mistakes, it is recommended to first connect the “minus” to ground, and only then connect the “plus” to the corresponding contact on the solenoid relay housing. When performing this operation, you should be careful, because when the starter is operating, a high current flows through the wires, so you can get a severe burn if you do not follow the safety rules.

How to remove bendix

In some cases, before removing the starter bendix, it is necessary to perform some actions that will significantly simplify this task. For example, in order to remove an old part and install a new spare part, you need to remove the starter from the car. If this operation has not been carried out for a long time, then the bolts of the electric motor may become so “stuck” to the housing that they cannot be unscrewed without the risk of destruction. In such a situation, you should use a penetrating lubricant, which should be applied to the bolt and wait 15 - 20 minutes. Then you need to tap the bolt heads a little with a small hammer and try to unscrew them. As a rule, such preparation and careful dismantling actions allow you to save fasteners for future use.

In the absence of lubrication, the acid bolt can be loosened using heating. For this purpose, you can use a gas burner. When using this method, it is important not to overheat the metal, so as not to deteriorate its mechanical qualities.

Some difficulties may also occur when removing the retaining ring that holds the bendix to the shaft. To perform this work, it is recommended to use a special mandrel. If it is not available, thin screwdrivers can be used to perform the operation, as well as pliers, which should be used as a puller.

The starter bendix is ​​a very important part of the car, but this spare part is relatively inexpensive. For example, for VAZ cars you can purchase a new part for less than 1 thousand rubles. When the first signs of a Bendix malfunction appear, it is recommended to immediately contact a car service for repair work or install a new spare part yourself. Untimely implementation of reconstructive surgery can lead to very undesirable consequences. The lack of reliable drive between the starter and crankshaft can be most dangerous when you need to quickly start the engine in an emergency.

Replacement

Necessary tool

• Phillips and flat head screwdriver
• Ratchet, extension and socket for “13mm” and “15mm”
• Open-end wrench for “10mm” and “13mm”
• Penetrating lubricant (WD-40)
• And the desire to repair your own car with your own hands.

Step-by-step replacement instructions

Work can be carried out both from the inspection hole and from above. We will consider the option of doing the work from above, as it is simpler and more convenient. And not everyone has an inspection hole.

• First of all, disconnect the negative terminal of the battery and remove the air filter housing along with the mass air flow sensor.

• Then, on the solenoid relay, use a 13mm open-end wrench to unscrew the power wire and remove the “mother” chip from the relay (marked with red arrows in the picture).

• Using a ratchet with a 13mm socket and an extension, unscrew the two starter mounting nuts. Below and above.

• Next, we remove the starter from the engine compartment and inspect it.

• We install it in the reverse order and check its functionality by test running the car.

Replacement from under the bottom of the car is similar to the instructions outlined above, but only to carry out work from an inspection hole or overpass it is necessary to remove the engine crankcase protection.