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 keys 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 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 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 here's the importance correct tightening many do not attach 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 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 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.
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.
A new bearing is installed in the knuckle. 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.
After replacing the wheel bearing, an important moment comes - tightening. It is necessary to clamp not with "bare" hands, but with the use of special device- torque wrench. Since the service life of the equipment and the quality of the control of the technical facility directly depend on the completeness of the tightening.
Each car has its own wheel bearing tightening torque. It is clearly described in the user manual. If for some reason the manual is lost, then you need to use the Internet or contact the nearest car repair shop for clarification.
Wheel bearing tightening
The tightening torque of a wheel bearing is usually called the actual force with which the hub nut is clamped. The force is measured in N/m or kg/m, depending on the magnitude and conversion task.
Each bearing in its design has a slight axial clearance. It is necessary for the correct operation of the mechanism, namely:
- to prevent displacement to the sides;
- reducing the actual friction force;
- uniform location of thermal expansion;
- voltage distribution;
- increase in contact area.
How to properly tighten a wheel bearing
The tightening value of the front and rear bearing calculated based on a number of factors, such as:
- Minimum and maximum allowable size(parameter) bearing.
- The value of the axial clearance.
- Type of thread pitch (coarse or fine).
The above list of data is of a template nature and in each specific situation can be supplemented by new factors. However, the aforementioned reasons remain the same regardless of the situation.
Wheel bearing torque
- VAZs, NIVA: from 19.6 to 24.6;
- brand Ford models Focus, Fusion, Mondeo, Transit: from 45 to 53;
- all Chevrolet models: 18.9 - 19.5 or 25.0 - 30.1;
- Renault models Duster, Megan, Sandero, Logan: 175 and 280;
- Opel various models: 150.
For preventive and repair work It is customary to use a torque wrench. This practice exists in SRT. A device with a scale is built into the design of the key. Knowing desired indicator, you can easily tighten the nut. The main thing is not to overdo it, as you can break the threads on the fastener.
Depending on the modification of the key, various limiters are set:
- unregulated;
- with adjustment;
- with tightening indicator;
- with installed digital display.
Depending on the selected type of torque wrench, adjustment is carried out wheel bearings.
Often, owners ask the question: is it possible to tighten wheel bearings without actually having a torque wrench. It's not allowed, but it's not recommended either. Since you can not calculate the effort. The consequences of such tightening are obvious: backlash and premature exit out of service.
Now you know how to adjust the wheel bearing on your own. Despite the simplicity of the actions and the design of the mechanism, it is recommended to service your technical tool in specialized auto repair shops in order to avoid negative consequences and damage to adjacent parts.
Before carrying out preventive measures, do not forget to purchase only high-quality and original components recommended or approved by the manufacturer. This will increase the service life technical means and reduce the number of breakdowns to a minimum.
Unlike many car owners foreign brands, the owners of the VAZ "classics" know how the wheel bearings are adjusted. Currently, among designers and auto engineers, the opinion prevails that fixed and non-separable front hub bearings are safer. We can only partly agree with this. new bearing changes along with the hub into which it is pressed at the factory.
Whether we like it or not, wear and tear is inevitable. After some time, a backlash appears and there is only one way out - to buy an expensive bearing with a hub. domestic auto industry stands on the side of our motorists.
It is much easier to replace only the bearings, which allow you to periodically adjust the play of the hub. First, it is much cheaper. Secondly, the resource of the node increases. Thirdly, the adjustment can be made by the driver himself in a garage.
Why is wheel bearing adjustment possible on some vehicles?
Considering that the design of the classic VAZ series is borrowed from foreign cars, there are foreign cars in which the play of the front wheel bearings is adjustable. This possibility is provided by the special design of the front wheel hub, which rotates on the axle shaft on two conical (tapered) bearings.
A distinctive feature of the conical ones is that you can set the play between the hub and the axle shaft by pressing the outer and inner races of the bearings against each other. In the hub, in the direction of the cones, the bearings are directed towards each other. If you gradually tighten the hub nut on the axle shaft, this will lead to a stronger pressing of the rollers between the clips. At some point, the wheel will stop spinning altogether.
Thus, with the help of a single nut, it is possible to regulate the force with which the clips press the rollers. During operation, even heavy-duty bearing metal alloys wear out, which leads to excessive wear. This endangers the life and health of both the driver with passengers and other participants. traffic. All that needs to be done to fix this problem is to tighten and fix the hub nut. As soon as the nut at maximum clamping ceases to affect the amount of play, it is necessary to change the bearings.
Wheel bearing adjustment - step by step instructions
Before proceeding with the regulatory process, it is necessary to carry out certain preparatory actions. For such an important event, in fact, you need a minimum of tools:
- jack;
- hammer;
- screwdriver;
- beard
- wrenches for wheel bolts on "12", "27";
- torque wrench.
With each adjustment, the bearing play must be changed. hub nuts. The nut is fixed on the axle shaft in the required position by riveting the collar of the nut into the groove on the axle shaft. If the shoulder is bent and bent again, then it is likely that the nut will return to its previous position.
With everything you need at hand, you can begin to adjust the wheel bearings.
Wheel bearing adjustment technology:
- the vehicle is parked on a level surface parking brake or other improvised means;
- raised with a jack front wheel, after which it is removed together with decorative caps;
- carefully, using a hammer, screwdriver or other spacer, the protective cap of the hub is pressed out;
- the wheel is mounted on the hub and twisted with at least two oppositely located bolts;
- the amount of backlash and the possibility of tightening are checked for which: with one hand, hold the wheel in the upper part and make sharp rocking movements to the sides in the direction of the wheel axis, and with the other hand, press the washer located between the nut and the bearing race. If the axial clearance is more than 0.02 - 0.08 mm, it should be taken for regulation;
- using a hammer and a pointed metal object (beard, core), it is necessary to unlock the bent sections of the collar of the hub nut;
- the nut is unscrewed and removed, a new one is screwed on instead (on the right trunnion, a nut with a left-hand thread, on the left trunnion - on the right);
- after tightening the nut with a force of 19.6 Nm, it is necessary to turn the hub several times in different directions so that the bearing rollers take their place;
- the nut is loosened and re-tightened, but with a force of 6.8 Nm. For reference: 10 Nm = 1.02 kg / cm 2;
- the nut is turned off at an angle of about 25 degrees;
- the shoulder of the nut is jammed into the grooves on the axle shaft of the steering knuckle;
- the hub is assembled and the wheel is installed.
Adjusting the wheel bearings is a very important and responsible matter, because the safety of people depends on how everything is done correctly. In addition to strictly following all the rules, you need to know and take into account such aspects as:
- tightening degree of the hub nut;
- bearing lubrication condition.
Some drivers mistakenly believe that tightening the nut tighter will extend the mileage. After the nut is fixed, the wheel must rotate absolutely freely and the specified minimum technological play must be present. In motion, all parts of the bearing heat up and expand. If you overdo it and tightly tighten the nut, this can even lead to jamming or destruction of the bearing.
The bearings in the hub must be generously lubricated. During operation, the lubricant has a destructive effect: friction, overheating, the appearance of impurities of abraded metal. If it's time to adjust bearing play, don't save money on buying new grease. As a rule, Litol-24 is universal for wheel bearings. Lubrication is one of the important conditions for increasing the service life of bearings.
Repairing your own 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 true 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 of the torque wrenches sold in stores are not designed for the huge tightening torque that the hub nut requires. In this short article, we will consider 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, as well as domestic domestic cars(front-wheel drive) began to install ball (or roller) double-row bearings (or single-row with a thrust collar). And finally there was no need correct adjustment tapered bearings, in which for many, adjusting the required clearance was not an easy task.
Since in modern non-tapered bearings, the axial clearance is set by the bearing manufacturer (we read about their marking and bearings here) and no adjustments need to be made when assembling the assembly.
But here is the importance of correctly tightening such bearings, and right nuts hubs, many do not attach, but in vain.
Hub assembly VAZ 2108 with double row bearing
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 common on domestic front wheel drive vehicles(VAZ 2108) hub assembly, 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 completely close and the upcoming convergence of the ball raceways will be unrealistic. 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 required clearance of 0.06 - 0.08 mm), in other words, 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 violation and the holder of the required clearance. And the more accurate the tightening torque of this nut, prescribed by the factory, the longer the required clearance in the bearing will be provided.
hub nut - right moments puffs.
The required tightening torque for the hub nut is prescribed not by the bearing manufacturer, but by the plant and the vehicle manufacturer. various machines differs little (for example, in the VAZ 2108, the moment forms 225.6 - 247 N m, in other words, 23 - 25 kgf m).
Based on this, it must be specified in the factory tips of your own car.
It is noteworthy that tips on the tightening torque of the same bearing can vary slightly from different car factories. This probably depends on the different strength of the metal of the hubs, pins, nuts or threads on the shank.
And this strength of the metal from which it is all made is known only by the car manufacturer.
For example, as I said, the tightening torque of the hub bearing on a VAZ2108 car, its plant recommends 23 - 25 kgf m, and in order for the bearing, the AZLK plant (for Moskvich) prescribes only 14 - 16 kgf m, and the Muscovite plant does not allow no way be more that value.
And it is possible to tighten such a bearing even stronger, since they do it on VAZs, as well as a smaller bearing for the Oka car (marking 6-256706U1S17) and even then it is tightened harder, with a moment of 19 - 23 kgf m. Surely the hubs and material , or the threads of the CV joint shank in Moskvich are not stronger than on VAZ cars.
Despite the fact that the same M20x1.5 thread is cut on truck nuts and ZIL wheel studs, they are tightened with a torque of as much as 60 kgf m, and nothing.
Well, for "Tavria" (1102), its plant chose the "moment" and the middle of the tightening in order for the bearing, (as on the eight and forty-first Moskvich) to form 15 - 20 kgf m.
to take into account one more fundamental point: during the operation of the car, the moment of the nut tightened at the factory can slowly weaken, moreover, at a time when the bearing life still allows you to drive and drive. The tightening torque slowly weakens due to the transformation of the metal structure, and suddenly the tightening weakens, then the clearance in the bearing becomes larger.
And also a slight increase in this gap of 0.06 - 0.08 mm (between their tracks and balls) significantly reduces the bearing life, especially when traveling on domestic bad roads.
So it is useful to tighten the hub nuts after approximately 20,000 km of run (or control their tightening), just as they tighten the engine head bolts after a certain run. Along with this, it is useful to unscrew the hub nut one turn and tighten again. After that, we jack up the car and rotate the wheel a couple of times forward and backward, and after that we lower the car onto the asphalt and tighten the nut already with the required torque.
As I said at the beginning of the article, most of the torque wrenches on sale are not calculated at the moment of 25 kgf m, and some car owners have by and large there is no torque wrench. And the ratchet knobs of most tool kits are also not calculated at that moment. Their ratchet can break at any second from hardening (if you extend the lever through the pipe), and possibly cripple. There is, of course, a quality ratchet tool designed for such hardening, but it is quite expensive and not everyone has it.
Yes, and of course they will not “catch” the required moment.
It is possible to tighten the hub nut correctly and with the required torque in two ways, and moreover, they can be inexpensive. The first option: this is to weld a wonderful lever to the end head, and I will write a little below about the required length of this lever.
By the way, on sale it is possible to find, instead of a head, a wonderful tubular (box) key, and the thickness of the pipe wall in order for the key to be decent enough. In this vein, there are holes for a wonderful wrench or mount.
But it is possible, by means of 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 key for trucks on sale, and such a key (for example, 30-32 or 27-30) can easily withstand the tightening torque up to 30 kgf m. It can be bought in special stores for Kamaz, GAZ, Ural trucks, ZIL, or imported heavy vehicles.
The length of the lever can be lengthened with a pipe, but it is not uncommon 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 end head is 40 centimeters, and the weight of a person weighs 70 kilograms, then the tightening torque will be 28 kgf m. But in most cases, drivers put a meter pipe on the key and put pressure on everyone weighing (sometimes 90 - 100 kg), this is approximately twice as much as needed.
After tightening the nuts, they do not need to be countered with a washer (or cotter pin), as was the case on older cars with tapered bearings, since the nuts have locking belts.
Either there are self-locking compression nuts, or their soft belts, which are pressed into the groove of the trunnion.
I keep hoping this article will help novice drivers properly tighten the hub nut (or hubs), and significantly extend the life of your wheel hub bearing, good luck to everyone.
