How to replace bendix, fault diagnosis and causes of failure

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.

Design and principle of operation

Most overrunning clutches (let's call them the more popular word among motorists - bendix) consist of a driving race (or outer ring) containing rollers and pressure springs, as well as a driven race . The leading holder has wedge channels, which on one side have a significant width. It is in them that the spring-loaded rollers rotate. In the narrow part of the channel, the rollers are locked between the driving and driven clips. As is clear from the above, the role of the springs is to drive the rollers into the narrow part of the channels.

The principle of Bendix operation is the inertial effect on the gear coupling that is part of it until it engages with the engine flywheel. While the starter is inoperative (the engine is turned off or running in constant mode), the Bendix clutch is not engaged with the flywheel crown.

Bendix works according to the following algorithm:

Bendix interior

1. The ignition key is turned and current from the battery is supplied to the starter motor, driving its armature.
2. Thanks to the helical grooves on the inside of the coupling and the rotational movement, the coupling, under its own weight, slides along the splines until it engages with the flywheel.
3. Under the action of the drive gear, the driven cage with the gear begins to rotate.
4. If the teeth of the clutch and the flywheel do not coincide, it rotates slightly until they are firmly engaged with each other.
5. The buffer spring included in the design serves to soften the starting moment of the engine. In addition, it is needed to prevent tooth breakage from impact when the gears engage.
6. When the engine starts, it begins to rotate the flywheel at a higher angular speed than the starter previously rotated. Therefore, the coupling twists in the opposite direction and slides along the splines of the armature or gearbox (in the case of using a geared bendix) and disengages with the flywheel. This saves the starter, which is not designed to operate at high speeds.

How to check starter bendix

If the starter bendix does not turn, then you can check its operation in two ways - visually , by removing it from the car, and “by ear” . Let's start the description with the latter, as it is simpler.

As stated above, the main function of the bendix is ​​to engage the flywheel and spin the engine. Therefore, if at the moment of starting the engine you hear that the starter motor is spinning, and characteristic metallic clanging sounds - this is the first sign of a Bendix malfunction .

So then it is necessary to dismantle the starter and disassemble the bendix in order to inspect it in detail and determine the damage. The removal and replacement procedure is described below.

And so, the bendix was removed, it is necessary to inspect it. In particular, check whether it rotates only in one direction (if it turns in both, it means it needs to be replaced) and whether the teeth are eaten. Also check to see if the spring has weakened. You should also remove the fork from the Bendix, check its integrity, signs of wear, and if necessary, replace it. In addition, be sure to check if there is any play on the armature shaft. If this occurs, then the bendix should be replaced.

VAZ 2114 starter – connection diagram, device, technical characteristics

The starter installed on the VAZ model we are interested in is type 5712.3708.

It is a DC motor with a traction two-winding electromagnetic relay and a planetary gearbox.

The device is excited by permanent magnets. Its rated power is 1.55 kW and the current is:

The starter devices and its operation diagram are as follows:

• four permanent magnets are placed in the stator (in its housing);
• liners made of metal-ceramic material are mounted in the support and cover, in which the rotation of the armature shaft is carried out;
• the planetary gearbox imparts movement to the drive shaft from the armature shaft;
• the front end of the drive shaft rotates in a cermet bushing, which is built into the clutch housing;
• The movement of planetary gears occurs on needle-type bearings;
• when the device we are considering is turned on, the voltage from the battery is supplied through the ignition switch to the windings (there are two of them) of the traction relay, and after its contacts close, the retractor winding is switched off.

Possible causes of failure

As mentioned above, gear rotation is only possible in the direction of rotation of the starter armature. If rotation in the opposite direction is possible, this is an obvious malfunction, that is, the bendix must be repaired or replaced. There may be several reasons for this:

• Reduction in the diameter of the working rollers in the cage due to natural wear. The way out is to select and purchase balls of a similar diameter. Some car enthusiasts use other metal objects, such as pieces of a drill, instead of balls. However, we still do not recommend doing it yourself, but buying balls of the required diameter.
• The presence on one side of the roller of flat surfaces formed due to natural wear. Repair recommendations are similar to the previous paragraph.
• Grinding the working surfaces of the driving or driven race in those places where they come into contact with the rollers. In this case, repair is hardly possible, since such excavation cannot be removed. That is, it is necessary to replace the bendix.

Note! It is often better to completely replace the bendix than to repair it. This is due to the fact that its individual parts wear out approximately equally. Therefore, if one part fails, the others will soon fail as well. Accordingly, the unit will have to be repaired again.

Another reason for failure is wear of the gear teeth. Since this happens for natural reasons, repair in this case is impossible. It is necessary to either replace the mentioned gear or the entire Bendix.

Since the starter not only experiences heavy loads, but also comes into contact with the external environment and is susceptible to irritants such as moisture, dust, dirt and oil, freewheeling can also occur due to deposits in its grooves and rollers. A sign of such a malfunction is the noise of the armature when the starter is started and the immobility of the crankshaft.

Installation

• We insert the VAZ 2105 starter into the seat.
• Then secure it with three mounting bolts.
• Then you should reinstall the starter shield.
• Now the next step is to connect back all the necessary wires to the solenoid relay.
• Next, reinstall the braces (on an injection-powered car) or install the air filter housing (on a carburetor car).
• Connect the negative terminal back to the battery and you can try to start your favorite car.

Brief conclusion. Repairing a starter with your own hands is not a difficult task, but quite economical. The price of spare parts plus the price for work by craftsmen at the nearest service station is already good money. And so you will only have to spend money on spare parts. We hope this article helped you. Take care of your car, have it repaired on time, and when you really need it, it will serve you faithfully!

Source

How to change bendix on the starter

As a rule, in order to change the bendix, you need to remove the starter and disassemble it. Depending on the machine model, the procedure may have its own characteristics. We will describe the algorithm from the moment when the starter has already been removed and to replace the bendix it is necessary to disassemble its housing:

Bendix repair

• Unscrew the tightening bolts and open the housing.
• Unscrew the bolts securing the solenoid relay, and then remove the latter. When repairing, it is advisable to clean and wash all the insides.
• Remove the bendix directly from the axle. To do this, you need to knock down the washer and pick out the restrictive ring.
• Before installing a new bendix, the axle must be lubricated with temperature grease (but without excess).
• Typically, the most difficult procedure involves installing the retaining ring and washer. To solve this problem, craftsmen use different methods - they open the ring with open-end wrenches, use special clamps, sliding pliers, and so on.
• After the bendix is ​​installed, lubricate all rubbing parts of the starter with high-temperature grease. However, do not overdo it with the amount, because excess will only interfere with the operation of the mechanism.
• Check the starter before installation. To do this, use wires to “light” the car in winter. With their help, supply voltage directly from the battery. Connect the “minus” to the starter housing, and the “plus” to the control contact of the solenoid relay. If the system is working properly, you should hear a click and the bendix should move forward. If this does not happen, it is necessary to replace the retractor.

Bendix repair

Replacing the bendix on the starter

Some tips from experienced drivers

Here are some tips from experienced motorists that will help you avoid possible problems and inconveniences when repairing or replacing a Bendix:

• Before installing a new or repaired bendix, always check its operation and the drive of the unit.
• All plastic washers must be intact.
• When buying a new Bendix, it is advisable to have the old one with you in order to verify their identity. Often similar parts have minor differences that are not visually memorable.
• If you are disassembling a Bendix for the first time, it is advisable to write down the process on paper or put the individual parts in the order in which they are dismantled. Or use the manual with photographs, video instructions above, and so on.

Replacement

In order to save a little money, you can replace the starter yourself, especially since this will require the following tools:

• keys for 8 and 13;
• WD-40 liquid.

It is better to carry out work under a canopy or in a garage.

Due to the fact that getting to the starter is not very convenient, we will simplify our task by removing the air filter housing. To do this, disconnect the contacts of the mass air flow sensor, release the pipes from the body, and then use a 8mm wrench to unscrew the two bolts securing the front support brackets.

Having carried out the preparatory work, we proceed to the main thing - replacing the starter. We carry out the work in the following sequence:

1. We de-energize the electrical circuit of the car by removing the “negative” terminal from the battery.
2. We treat the threaded connections attaching the starter to the gearbox with WD-40.
3. Disconnect the negative terminal of the solenoid relay (red wire).
4. Using a 13mm wrench, unscrew the nut securing the “positive” terminal.

Using a 13mm wrench, unscrew the three starter mounting nuts.

• Remove the starter from the studs.

We carry out the work on installing a new spare part in the reverse order, lubricating the studs located on the gearbox with graphite lubricant, which will help in the future to reduce the time for unscrewing if you need to remove the starter for any reason.

Price issue

Finally, it’s worth adding that Bendix is ​​an inexpensive spare part. For example, a Bendix VAZ 2101 (as well as other “classic” VAZs) costs about $5...6, catalog number is DR001C3. And the price of Bendix (no. 1006209923) for VAZ 2108-2110 cars is $12...15. The cost of Bendix for FORD cars of the Focus, Fiesta and Fusion brands is about 10...11 $. (cat. no. 1006209804). For TOYOTA Avensis and Corolla cars Bendix 1006209695 - $9...12.

Thus, repairs are often impractical for Bendix. It's easier to buy a new one and simply replace it. Moreover, when repairing individual parts, there is a high probability of rapid failure of others.