How to tighten front wheel bearing. The Importance of Properly Tightening a Car Wheel Nut

How to tighten front wheel bearing. The Importance of Properly Tightening a Car Wheel Nut

By correctly identifying how hard to tighten hub nut and by stopping in time, you can avoid thread stripping and the need to carry out costly repairs, given today's prices for nuts. Masters perform this work using a special torque wrench. Because the wheel bearing the product is quite capricious and is not always at hand optional equipment it is very important to know the answer to this question. Before work, it does not interfere with determining what kind of it is installed, for example, it can be conical or roller.

Features of tightening the hub nut

Not understanding with how hard to tighten wheel nuts Better not take this job. If they are pulled, then a breakdown will occur, and if you do not hold out, then in this case scrolling may occur, seat under the bearing will deteriorate. Anyone who is not sure of their knowledge can use the spring cantor, but you can get by with more in a simple way. Ratchet wrenches most often cannot provide sufficient force, and the tools designed for this are expensive.

To prevent damage and do the job correctly, for broach it is recommended to use a lever with a length of a meter or a little more. If a small thread pitch on a car hub can take a force of 20 Nm, plus it will be necessary to turn the key another 90 °, in total such efforts will give a very decent tightening torque. Who remembers physics can make a simple calculation. To do this, you need to know your weight and the length of the lever. A value of 20 Nm is equal to a force of two kilograms with a lever length of a meter.

Effort then how much torque to tighten the hub nut, depends on the individual vehicle. Tightening recommendations for even the same bearing often vary. They depend on the quality of the metal of the hubs, the strength of the nuts, pins, threads. Usually 19-23 kgf/m is sufficient. If the bearing weakens and the gap reaches a value of 0.06-0.08 millimeters, this will significantly affect the reduction in the resource of the entire mechanism.

Specialists who have worked in a car service for many years recommend tightening the hub nuts every 15-20 thousand kilometers. It will be useful in this case to relax them a little by one or two turns. It is best to have the car jacked up while doing this. For implementation this process many advise using a tubular wrench, a box wrench, because it has thick walls and there is a place for a crank, and it is more powerful. Thanks to a special adapter, it will be possible to use a pipe.

Modern cars are equipped with compression nuts that do not need to be countersunk. They have belts and they themselves will be pressed into the grooves of the trunnion. No need to press on the key with all your weight of one hundred kilograms, it is actually twice as strong as necessary. Knowing exactly what is the tightening torque of the hub nut it is possible to avoid losing a wheel on the way, before that a knock will occur when cornering, while the car may fly into a ditch.

The torque of the front wheel bearing is the torque with which the hub nut is tightened. Units of measurement - N * M (or kgf * m).
The front bearings have internal axial clearance, which is necessary for correct operation bearing, namely:

  • prevention of angular displacement of the rings;
  • reduction of friction of rolling elements and raceways;
  • correct distribution of internal stresses on separators and clips.
  • thermal expansion compensation.
  • increased contact angle for axial loads.

In turn, the axial internal clearance of a double-row ball bearing is the amount by which the inner rings relative to the outer ring move. In order for the axial clearance to be allowed, the ball bearing (or roller bearing) is adjusted, this is done using correct tightening hub nuts.

Familiarize yourself with the mounting and layout of the bearing with the front hub, as well as with the design of the wheel bearing.

The video also shows the process of adjusting the backlash by the level of tension of the locknut:

How much torque to tighten the hub nut on your car?

Torque standards are set for each car, since the tightening force for the locknut depends on the following factors:
- bearing dimensions;
- Regulated axial clearance;
- Diameter and thread pitch;
The following are indicators of effort in order to properly tighten the nut. The base will be gradually replenished.

Advice:

If you did not find the tightening torque values ​​​​for your car (Skoda Octavia, Subaru models, Toyota Corolla), find the bearing you have installed, and the same thread diameter, or ask a question in the comments.

Tightening torques for the front wheel bearing on the VAZ (LADA)

Tightening torques for front wheel bearing for Ford

Tightening torques for the front wheel bearing on a Chevrolet (Chevrolet)

Tightening torques for the front wheel bearing on Renault (Renault)

ABING
1 Logan 175 M20x1.5
2 Megan 1, Megan 2 280
3 Sandero
4 Duster 4x4 280
5 Duster 4x2 175

Tightening torques for the front wheel bearing on Daewoo (Daewoo)

How to tighten the hub nut to the right torque

For tightening threaded connections where a specific torque is recommended, use special torque wrenches. Inside the tool is a dynamometer with a scale or special device with a limiter, which is triggered when the required tightening force is reached. The keys also come with value intervals, for example 5-25 (minimum 5 Nm, maximum 25 Nm).
Threaded connection tighten until the arrow shows the required value or the limiter works. There are also expensive and accurate analogues - with an electronic display, but for maintenance and repair passenger cars a mechanical option would work.

The photo shows the main types of such keys.

  1. With preset torque, not adjustable.
  1. With pre-set torque value, adjustable.
  1. With torque indicator.
  1. With digital display of applied torque.

Watch the video on how to use the torque tool:

How to tighten a hub nut without a torque wrench

Many motorists, when repairing their car, consider it inappropriate to purchase torque wrenches or other specialized devices (pullers, etc.). Available good way to tighten the fastener to the correct torque without using a dynamometer.
The following fixtures will be required:
1. Ratchet with locknut head;
2. Pipe for extending the ratchet to create the required "shoulder";
3. Roulette;
4. Marker;
5. Cargo, with the ability to hang on the "shoulder" (for example, a weight of 32 kg).

The essence of the method is to calculate the moment according to the formula from primary school physics:

P - applied force, N;
l - distance from the hub to the point of application of force - "shoulder", m.
The finished formula for our case will be as follows:

P1 \u003d (M2 100) / (M1 10) (10 (or 9.8) - translated into Newtons), where

P1 - the distance at which the sinker is attached to the "shoulder" relative to the torsion point, cm;
M1 - weight of cargo, kg;
M2 - required moment, N m.

Calculation example for a Ford Focus 2 car

P1 \u003d (M2 100) / (M1 10) ( 10 (or 9.8) \u003d (45 100) / (32 10) \u003d 4500/320 \u003d 14 cm.
Conclusion: to ensure a tightening torque of 45 N m, a sinker weighing 32 kg is required, located on the pipe at a distance of 14 cm.

Sequencing:

  1. Pre-tighten the locknut and tighten slightly.
  2. We mark a distance of 14 cm, where the rod should hang;
  3. We hold the ratchet with one hand, and with the other we hang the sinker, thereby tightening the mount;
  4. The operation continues until the fasteners under the weight no longer tighten, which means that we have reached the required force. Accuracy +/- 5%.

Useful videos

How to do without a torque wrench:

Proper hub nut tightening:

How to tighten the hub nut and with what torque Tips, reviews, instructions, services

The torque of the front wheel bearing is the torque with which the hub nut is tightened. Units of measurement - N * M (or kgf * m). Front bearings have internal axial clearance, which is necessary for the correct operation of the bearing, namely:

  • prevention of angular displacement of the rings;
  • reduction of friction of rolling elements and raceways;
  • correct distribution of internal stresses on separators and clips.
  • thermal expansion compensation.
  • increased contact angle for axial loads.

In turn, the axial internal clearance of a double-row ball bearing is the amount by which the inner rings relative to the outer ring move. In order for the axial clearance to be allowed, the ball bearing (or roller bearing) is adjusted, this is done by correctly tightening the hub nut. Familiarize yourself with the mounting and layout of the bearing with the front hub, as well as with the design of the wheel bearing.

The video shows the process of adjusting the backlash by the level of tension of the locknut:

Torque standards are set for each car, since the tightening force for the locknut depends on the following factors: - Bearing dimensions; - Regulated axial clearance; - Thread diameter and pitch;

If you did not find the tightening torques for your car (Skoda Octavia, Subaru models, Tayota Corolla), find the bearing you have installed, and the same thread diameter, or ask a question in the comments.

Tightening torques for the front wheel bearing on the VAZ (LADA)

Tightening torques for front wheel bearing for Ford

Tightening torques for the front wheel bearing on a Chevrolet (Chevrolet)

Tightening torques for the front wheel bearing on Renault (Renault)

A B C D
1 Logan 175 M20x1.5
2 Megan 1, Megan 2 280
3 Sandero
4 Duster 4x4 280
5 Duster 4x2 175

Tightening torques for the front wheel bearing on Daewoo (Daewoo)

How to tighten the hub nut to the right torque

To tighten threaded connections, where it is recommended to observe a certain moment, special torque wrenches are used. Inside the tool there is a dynamometer with a scale or a special device with a limiter, which is triggered when the required tightening force is reached. The keys also come with value intervals, for example 5-25 (minimum 5 Nm, maximum 25 Nm). The threaded connection is tightened until the arrow shows the required value or the limiter works. There are also expensive and accurate analogues - with an electronic display, but a mechanical version is suitable for the operation and repair of passenger cars.

The photo shows the main types of such keys.

  1. With preset torque, not adjustable.
  1. With pre-set torque value, adjustable.
  1. With torque indicator.
  1. With digital display of applied torque.

Watch the video on how to use the torque tool:

Many motorists, when repairing their car, consider it inappropriate to purchase torque wrenches or other specialized devices (pullers, etc.). There is a good way to tighten the fastener to the right amount without using a dynamometer. You will need the following accessories: 1. Ratchet with locknut head; 2. Pipe for extending the ratchet to create the required "shoulder"; 3. Roulette;4. Marker;

5. Cargo, with the ability to hang on the "shoulder" (for example, a weight of 32 kg).

The essence of the method is to calculate the moment according to the formula from the primary classes of physics:

P - applied force, N; l - distance from the hub to the point of application of force - "shoulder", m.

The finished formula for our case will be as follows:

P1 \u003d (M2 100) / (M1 10) ( 10 (or 9.8) - translated into Newtons), where

P1 - distance at which the sinker is attached to the "shoulder" relative to the torsion point, cm; M1 - weight of the load, kg;

M2 - required moment, N m.

Calculation example for a Ford Focus 2 car

P1 \u003d (M2 100) / (M1 10) ( 10 (or 9.8) \u003d (45 100) / (32 10) \u003d 4500/320 \u003d 14 cm. Conclusion: to ensure a tightening torque of 45 N m, a sinker with a mass of 32 kg, located on the pipe at a distance of 14 cm.

Sequencing:

  1. Pre-tighten the locknut and tighten slightly.
  2. We mark a distance of 14 cm, where the rod should hang;
  3. We hold the ratchet with one hand, and with the other we hang the sinker, thereby tightening the mount;
  4. The operation continues until the fasteners under the weight no longer tighten, which means that we have reached the required force. Accuracy +/- 5%.

The video shows examples of the correct tightening of the hub nut:

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Wheel bearing tightening torque

Designer's Handbook a useful site for a mechanical engineer

In a vehicle, wheel bearings are subjected to extreme loads: high temperature fluctuations, different actions the surrounding sphere, as well as, in the effect of the perception of shocks from the side of the irregularities of the track, drive, brakes and steering - different dynamic loads. Under these circumstances, wheel bearings should be inspected regularly. In this case, it is necessary to pay attention to the fact that the wheel must rotate without play, with permissible noise and minimal friction.

Some modern wheel bearings are equipped with a multi-pole magnetic ring, so magnetic fields must be avoided when storing and mounting such bearings. Otherwise, they may become unusable.

CX supplies these bearings with a metal protective cover made of special alloy steel.

It protects the multi-pole ring from unwanted demagnetization and must be released immediately before installation.

Also, when working with such bearings, it is necessary to inspect for correct installation.

The bearing must be mounted in such a way that the pole ring is directed towards the speed sensor.

The integration trend will lead to the fact that in the future, similar structural elements vehicle, such as expression count sensor and parts drive shaft will become constituent parts hub bearing. A couple of years ago, SKF and GKN showed close general development, where the wheel bearing and the axle shaft joint housing are one complete. The advantage of this highly integrated module is ease of installation, reduction in the number of unsuspended mass elements, which improves comfort, safety and lowers the required braking force. But that's not all.

FAG intends to bring the wheel bearing to the intermediate link between the wheel and the chassis with elements of change tractive effort engine.

Quite interesting is also the development of SKF, which allows the supply of air to the wheels, which makes it possible to apply pressure regulation in tires.

With this type, the wheel bearings have a great potential for tasks, combined, first of all, with increasing the safety of the car.

On the drive axles, so-called diagonal ball bearings are used. From their name it is clear that the balls are not placed in half of the body, but are removed to the country. As a result, they accept lateral loads well, but in this case, more wear must be expected.

The decisive factor for the longevity of diagonal ball bearings is the tightening tension, which is closely related to the geometry and accuracy of the compound lobes, as well as to the tightening torque of the central nut.

At the end of the series of articles on bearings, let's take a look at the methods and features of replacing these details. This is one of the most common operations on the service, here, it would seem, everything has long been known. But it is precisely here that most often there is a violation of technologies, called both by ignorance of these same technologies and a gap in the experiment, and by the lack of an appropriate tool. The former slogan "Without a sledgehammer and a chisel, you are not a locksmith, but ..." does not work anymore.

And therefore we will start from scratch.

The backlash must be taken in accordance with the manufacturer's requirements. The last one is the one that cannot be canceled directly related to security.

This is the manufacturer's recommended tightening torque for the hub nut.

Important: when tightening the hub nut wheel hub should apply. In this case, the tapered rollers must take their proper position in close driving roads.

If there are no backlash requirements, bearing manufacturers recommend that the hub nut be tightened (loosened) with a similar type so that the lock washer can be radially moved with a screwdriver.

But at the same time it is necessary to avoid trimming the component parts (principle of leverage).

It must also be remembered that correct installation bearing play is important for function ABS sensor, because for this reason, violations in the brake system are not often found.

To sum up, it must be seen that even if the current development of wheel bearings implies less workshop employment for workshops, this topic remains an extremely good source of income for free workshops. First of all, because in the segment of cars 2 and 3 (5 - 15 years) there is the highest potential for wear repairs.

Designer's Handbook - Everything any designer needs! ©2008-2017

SpravConstr.ru

The importance of properly tightening the car wheel hub nut.

Repairing your front wheel drive car, for example, changing the CV joint, wheel bearing, or dismantling the gearbox, many drivers have to unscrew and tighten the wheel hub nut. But this is not as easy as it seems from the outside, and the nut must be tightened with a certain moment, otherwise there is a risk of the bearing turning on the hub and its subsequent repair. In addition, most torque wrenches sold in stores are not designed for big moment tightening required by the hub nut. In this short article, we will look at the importance of this seemingly simple operation, and how to do without a torque wrench.

In the 80s of the last century, they finally abandoned conical roller bearings, and even on our domestic cars(front-wheel drive) began to install ball (or roller) double-row bearings (or single-row with a thrust collar). And finally, the need for fine adjustment of tapered bearings was eliminated, in which for many, adjusting the required clearance was a difficult task.

Indeed, in modern non-tapered bearings, the axial clearance is set by the bearing manufacturer (read about bearings and their marking here) and no adjustments are required when assembling the assembly. But many do not attach importance to the correct tightening of such bearings, or rather the hub nuts, but in vain.

Hub assembly VAZ 2108 with a double-row bearing 1 - halves of the inner bearing race, 2 - outer bearing race, 3 - balls, 4 - bearing cage, 5 - CV joint tip (trunnion), 6 - washer, 7 - nut.

For example, let's take a common on our front wheel drive cars(VAZ 2108) hub assembly, with two-row ball bearing(its marking is 6-256907E2C17), shown in the figure on the left. If you tighten the hub nut 7 on the thread of the CV joint end, then the halves of the inner race of the bearing will close completely and further convergence of the ball raceways will no longer be possible. And in such a clamped state, the axial clearance in the bearing will be approximately 0.06 - 0.08 mm.

This means that the hub nut 7 must hold the halves of the inner race of the bearing for a sufficiently long time (and provide the necessary clearance of 0.06 - 0.08 mm), that is, throughout the entire life of the bearing. And that means the nut should not allow an increase in the distance between the halves of the cage and a violation of the required clearance. And than right moment the tightening of this nut, prescribed by the factory, the longer the required clearance in the bearing will be maintained.

Hub nut - required tightening torques.

The necessary tightening torque for the hub nut is prescribed not by the bearing manufacturer, but by the car manufacturer, and this moment is different cars slightly different (for example, for a VAZ 2108, the moment is 225.6 - 247 N m, that is, 23 - 25 kgf m). Therefore, it is advisable to specify it in the factory recommendation of your car.

It is interesting that the recommendations for the tightening torque of the same bearing may differ slightly from different car factories. This most likely depends on the different strength of the metal of the hubs, pins, nuts or threads on the CV joint shank. And this strength of the metal from which all this is made is known only by the manufacturer of the machine.

For example, as I said, the tightening torque of the hub bearing on a VAZ2108 car, its plant recommends 23 - 25 kgf m, and for the same bearing, the AZLK plant (for Moskvich) prescribes only 14 - 16 kgf m, and the Muscovite plant does not allow in any way exceed this value.

And such a bearing can be tightened even stronger, because they do it on VAZs, and even the smaller bearing for the Oka car (marking 6-256706U1S17) is even tightened harder, with a moment of 19 - 23 kgf m. Most likely the material of the Moscow hub , or the threads of the CV joint shank in Moskvich are weaker than on VAZ cars. Although the same M20x1.5 thread is cut into wheel studs and the nuts of the ZIL truck, and they are tightened with a moment of as much as 60 kgf m, and nothing.

Well, for "Tavria" (1102), its plant chose the "middle" and the tightening torque of the same bearing (as on the eight and forty-first Moskvich) is 15 - 20 kgf m.

One more thing to consider important point: during operation of the car, the torque of the nut tightened at the factory may gradually weaken, moreover, when the bearing life still allows you to drive and drive. The tightening torque gradually weakens due to a change in the structure of the metal, and if the tightening weakens, then the clearance in the bearing becomes larger. And even a slight increase in this gap of 0.06 - 0.08 mm (between the balls and their tracks) quite significantly reduces the bearing life, especially when traveling on our roads. bad roads.

So it is useful to tighten the hub nuts after about 20,000 km of run (or check their tightening), just like tightening the engine head bolts after a certain mileage. In this case, it is useful to unscrew the hub nut one turn and tighten it again. Then we jack up the car and rotate the wheel several times back and forth, and then lower the car onto the asphalt and tighten the nut to the required torque.

As I said at the beginning of the article, most torque wrenches on sale are not designed for a moment of 25 kgf m, and some car owners do not have any torque wrench at all. And the ratchet knobs of most tool sets are also not designed for such a moment. Their ratchet can break at any time from such an effort (if you lengthen the lever with a pipe), and you can be crippled. Of course, there is a high-quality ratchet tool designed for such an effort, but it is very expensive and not everyone has it. Yes, and naturally they will not “catch” the required moment.

Correctly and with the required torque, there are two options for tightening the hub nut, and moreover, they can be quite inexpensive. The first option: this is to weld a powerful lever to the end head, and I will write a little lower about the required length of this lever.

By the way, on sale you can find, instead of a head, a powerful tubular (box) wrench, and the wall thickness of the pipe of such a wrench is quite decent. In this vein, there are holes for a powerful wrench or mount. But it is possible, using the adapter shown in the figure on the left, to attach a pipe of any length to such a key.

The second option is to look for a ready-made wrench for trucks on sale, and such a wrench (for example, 30-32 or 27-30) can easily withstand tightening torque up to 30 kgf m. It can be purchased at specialized stores for Kamaz, GAZ, Ural, ZIL trucks , or imported heavy vehicles.

The length of the lever can be extended with a pipe, but it is enough to step on the lever with all your weight. Moreover, the required tightening torque is easy to calculate. If the length of your key or a lever welded to the socket is 40 centimeters, and the weight of a person who weighs 70 kilograms is pressing on it, then the tightening torque will be 28 kgf m. But usually drivers put a meter pipe on the key and press with all the weight (sometimes in 90 - 100 kg), this is about twice as much as necessary.

Once the nut has been tightened, it is not necessary to counter it with a washer (or cotter pin) as was the case on older machines with tapered bearings, as the nuts have locking collars. Or there are self-locking compression nuts, or their soft belts, which are pressed into the groove of the trunnion.

I hope this article will help novice drivers to properly tighten the hub nut (or hubs), and significantly extend the life of your wheel hub bearing, good luck to everyone.

Such a parameter as the tightening torque of the front wheel bearing is extremely important, because if it is not maintained, the car will begin serious problems. First of all, an unpleasant knock will appear in the cabin, which will be heard from under the wheels while overcoming various bumps and pits.

Required tool

List of equipment for bearing replacement:

  • Large flathead screwdriver.
  • Set of wrenches.
  • Vice and chisel.
  • A pair of mounting type blades.
  • File.
  • Puller.
  • Locking elements for the wheel.
  • Jack.

As regards the necessary Supplies can't do without the following:

  • the bearing itself.
  • A little motor oil.
  • Specialized lubricant.

Action algorithm

Place Hyundai Solaris on a flat surface and place shoes under the wheels.

Raise the car with a jack and remove the wheel. You can only loosen the nuts when the car is on the ground.

Take a 32 wrench and use it to unscrew the hub nut, fixing brake disk flat screwdriver.

Remove the wheel speed sensor.

Remove brake disc.

Dismantle the tie rod ends and remove the ball joint.

Unscrew the steering knuckle mount from the steering knuckle strut and remove the latter.

As a rule, the inner ring remains, and the bearing breaks. The ring is knocked off with a chisel.

Now you can remove the bearing ring using the same mounting blades

Use a screwdriver to pry and pull out the retaining ring.

Press out the bearing with a puller.

When starting to replace a part, the seating surface must be properly prepared by cleaning it. After cleaning, apply engine oil or the previously mentioned liquid.

Is put new bearing into a fist. Press it in with a puller and install the locking element.

The last step is to install rounded fist to your place. It remains to tighten everything correctly so that the car drives quietly and gives true comfort to the driver.

According to the owner's manual, the torque of the front wheel bearing should be 88.3 - 107.9 Nm. This official information, which is given by the manufacturer, and therefore you should not improvise, since a lot depends on the effort applied. We can conclude that the procedure is not simple, but there is nothing supernatural in it, and therefore it will even turn out to save your own money.

Or dismantling the gearbox, many drivers have to unscrew and twist hub nut wheels. But this is not as easy as it seems from the outside, and the nut must be tightened with a certain moment, otherwise there may be a risk of the bearing turning on the hub and subsequent. In addition, most wrenches sold in stores are not designed for the large tightening torque that a hub nut requires. In this short article, we will look at the importance of this seemingly simple operation, and how to do without a torque wrench.

In the 80s of the last century, they finally abandoned tapered roller bearings, and even on our domestic machines (front-wheel drive) they began to install ball (or roller) double-row bearings (or single-row ones with a thrust shoulder). And finally, the need for fine adjustment of tapered bearings was eliminated, in which for many, adjusting the required clearance was a difficult task.

Indeed, in modern non-tapered bearings, the axial clearance is set by the bearing manufacturer (we read about bearings and their marking) and no adjustments are required when assembling the assembly. But many do not attach importance to the correct tightening of such bearings, or rather the hub nuts, but in vain.


1 - halves of the inner race of the bearing, 2 - outer race of the bearing, 3 - balls, 4 - bearing separator, 5 - CV joint tip (trunnion), 6 - washer, 7 - nut.

For example, let's take a hub assembly common on our front-wheel drive vehicles (VAZ 2108), with a double-row ball bearing (its marking is 6-256907E2C17), shown in the figure on the left. If you tighten the hub nut 7 on the thread of the CV joint end, then the halves of the inner race of the bearing will close completely and further convergence of the ball raceways will no longer be possible. And in such a clamped state, the axial clearance in the bearing will be approximately 0.06 - 0.08 mm.

This means that the hub nut 7 must hold the halves of the inner race of the bearing for a sufficiently long time (and provide the necessary clearance of 0.06 - 0.08 mm), that is, throughout the entire life of the bearing. And that means the nut should not allow an increase in the distance between the halves of the cage and a violation of the required clearance. And the more correct the tightening torque of this nut prescribed by the factory, the longer the required clearance in the bearing will be provided.

Hub Nut - Required Tightening Torques .

The necessary tightening torque for the hub nut is prescribed not by the bearing manufacturer, but by the car manufacturer, and this moment differs slightly for different cars (for example, for a VAZ 2108, the moment is 225.6 - 247 N m, that is, 23 - 25 kgf m). Therefore, it is advisable to specify it in the factory recommendation of your car.

It is interesting that the recommendations for the tightening torque of the same bearing may differ slightly from different car factories. This most likely depends on the different strength of the metal of the hubs, pins, nuts or threads on the CV joint shank. And this strength of the metal from which all this is made is known only by the manufacturer of the machine.

For example, as I said, the tightening torque of the hub bearing on a VAZ2108 car, its plant recommends 23 - 25 kgf m, and for the same bearing, the AZLK plant (for Moskvich) prescribes only 14 - 16 kgf m, and the Muscovite plant does not allow in any way exceed this value.

And such a bearing can be tightened even stronger, because they do it on VAZs, and even the smaller bearing for the Oka car (marking 6-256706U1S17) is even tightened harder, with a moment of 19 - 23 kgf m. Most likely the material of the Moscow hub , or the threads of the CV joint shank in Moskvich are weaker than on VAZ cars. Although the same M20x1.5 thread is cut on the wheel studs and nuts of the ZIL truck, and they are tightened with a moment of as much as 60 kgf m, and nothing.

Well, for "Tavria" (1102), its plant chose the "middle" and the tightening torque of the same bearing (as on the eight and forty-first Moskvich) is 15 - 20 kgf m.

One more important point should be taken into account: during the operation of the car, the moment of the nut tightened at the factory can gradually weaken, moreover, when the bearing resource still allows you to drive and drive. The tightening torque gradually weakens due to a change in the structure of the metal, and if the tightening weakens, then the clearance in the bearing becomes larger. And even a slight increase in this gap of 0.06 - 0.08 mm (between the balls and their tracks) quite significantly reduces the bearing life, especially when traveling on our bad roads.

So it is useful to tighten the hub nuts after about 20,000 km of run (or check their tightening), just like tightening the bolts after a certain run. In this case, it is useful to unscrew the hub nut one turn and tighten it again. Then we jack up the car and rotate the wheel several times back and forth, and then lower the car onto the asphalt and tighten the nut to the required torque.

As I said at the beginning of the article, most torque wrenches on sale are not designed for a moment of 25 kgf m, and some car owners do not have any torque wrench at all. And the ratchet knobs of most tool sets are also not designed for such a moment. Their ratchet can break at any time from such an effort (if you lengthen the lever with a pipe), and you can be crippled. Of course, there is a high-quality ratchet tool designed for such an effort, but it is very expensive and not everyone has it. Yes, and naturally they will not “catch” the required moment.

Correctly and with the required torque, there are two options for tightening the hub nut, and moreover, they can be quite inexpensive. The first option: this is to weld a powerful lever to the end head, and I will write a little lower about the required length of this lever.

By the way, on sale you can find, instead of a head, a powerful tubular (box) wrench, and the wall thickness of the pipe of such a wrench is quite decent. In this vein, there are holes for a powerful wrench or mount. But it is possible, using the adapter shown in the figure on the left, to attach a pipe of any length to such a key.

The second option is to look for a ready-made wrench for trucks on sale, and such a wrench (for example, 30-32 or 27-30) can easily withstand tightening torque up to 30 kgf m. It can be purchased at specialized stores for Kamaz, GAZ, Ural, ZIL trucks , or imported heavy vehicles.

The length of the lever can be extended with a pipe, but it is enough to step on the lever with all your weight. Moreover, the required tightening torque is easy to calculate. If the length of your key or a lever welded to the socket is 40 centimeters, and the weight of a person who weighs 70 kilograms is pressing on it, then the tightening torque will be 28 kgf m. But usually drivers put a meter pipe on the key and press with all the weight (sometimes in 90 - 100 kg), this is about twice as much as necessary.

Once the nut has been tightened, it is not necessary to counter it with a washer (or cotter pin) as was the case on older machines with tapered bearings, as the nuts have locking collars. Or there are self-locking compression nuts, or their soft belts, which are pressed into the groove of the trunnion.

I hope this article will help novice drivers to properly tighten the hub nut (or hubs), and significantly extend the life of your wheel hub bearing, good luck to everyone.

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