An engine breather (breathing valve) is a device for equalizing the pressure in a closed container relative to atmospheric pressure. In other words, the breather valve allows the closed container to communicate with the atmosphere. In internal combustion engines, the breather equalizes the pressure inside the engine crankcase.
During the operation of the vehicle and the operation of the power unit, the pressure in the crankcase may increase, as a result of which crankcase gases escape through the breather, excess engine oil is squeezed out, etc. If the pressure in the engine crankcase is below atmospheric pressure, then outside air enters the crankcase through the breather, thereby eliminating the difference between external atmospheric and internal pressure in the crankcase cavity.
We also recommend reading the article about what EGR is. From this article you will learn about the design, purpose and operating principles of the exhaust gas recirculation system.
Where is the breather installed?
Breathers on a car are installed:
in the engine itself; V.
What is a breather for?
The engine breather is part of the main unit in any car. A narrow-profile part that plays an important role during the operation of the main unit of the vehicle. The device looks like an auto valve. Breathers are installed to reduce pressure in the crankcase itself.
The device reduces pressure when gaseous substances are released from the engine housing, and it helps to quickly reduce pressure. In the automotive world you can find different cars. In some models and brands, breathers are installed not only in the engine, but also in the gearbox, for transfer cases, gearboxes and the rear axle of the car.
The principle of operation of the breather in the engine
Today, a breather valve to reduce pressure is very often installed on SUVs. This is due to the fact that the device is suitable for off-road driving. Breathers prevent oil leakage. The heated oil in the engine promotes expansion as a result.
A breather (or breathing valve) is a device by which a container communicates with the atmosphere to maintain equal pressure. In “simple” language, the breather releases air and gases that arise as a result of the operation of the car’s devices, which makes it possible for air to pass inside when the operation of the car’s mechanisms has stopped. This is necessary in order to restore equal pressure in two planes.
Where are breathers used?
In automotive practice, breathers can be found in the engine, gearbox, front axle, and rear axle. But at the same time, it performs the same functions anywhere.
Engine breather
The engine breather releases the gases and air passing through it that are created by the operation of the cylinders, thereby preventing oil from leaking from the crankcase.
If the engine stops working, the pressure in the crankcase space and the atmosphere is equalized by the intake of air from.
This can save you from more expensive repairs. In fact, the breather, although it seems like an insignificant detail, in practice is of great importance for the health of the power unit.
What is an engine breather? Before answering this question, it is important to understand what it is intended for. This is directly related to the principle of its operation. The main task of this device is.
On the upper plane of the head, the valve drive parts are fixed, which are closed with a lid with a cap 5. A breather 3 is mounted on the cap. It communicates the crankcase cavity with the atmosphere. The breather is necessary to prevent oil from being squeezed out through the crankcase seals by gases penetrating from the cylinders. Air and gases that have escaped from the cylinders into the crankcase come out through the breather. If, after stopping the engine, the pressure of the cooled air in it becomes below atmospheric pressure, the air enters the crankcase from the outside through the breather. Wire packing soaked in oil cleans the air of dust. In some engines, the breather is located on the side wall of the block (from the side of the rod chamber) or in the neck cover for pouring oil into the crankcase. Most car engines have forced crankcase ventilation.
A sump is attached to the lower plane of the crankcase, which serves as an oil reservoir and covers the lower part of the engine. At the connector site, the pan is sealed with a cork or paronite gasket.
Where is this seal located?
To be able to replace the rear axle gear oil seal, the first thing you need to do is find it. For this:
- drive the car into a viewing hole, or even better, an overpass (the work will be carried out under the car);
- tighten the handbrake;
- drain the oil from the rear axle gear housing;
- Locate where the driveline is attached to the rear flange.
It looks like this:
The blue arrow here indicates the rear flange of the gearbox, the green arrow indicates one of the bolts securing the cardan drive (there are 4 such bolts in the mount), and the red arrow shows the lock nut securing the flange itself.
In order to finally get to the oil seal itself (it is shown in the small photo), this entire assembly will need to be unscrewed, and from there it will only be a matter of little work.
But more on this a little later, while we deal with another, no less important issue.
Breather device
Typically, the internal structure of the breather is very simple. Let's look at it using the example of a breather for a gearbox/axle.
- External breather housing. It is made of metal, so it cannot be damaged while driving.
- Pressure spring. Thanks to it, the mechanism does not need an electrical/mechanical drive, everything is autonomous.
- Rubber gasket. It is this that ensures tightness when excess pressure is not released.
- Lock nut. The simplest method of fixation: although in other models there are a variety of options.
- The breather body itself. The through hole allows the unit to “breathe”, relieving excess pressure.
Although this breather is not used for engines, the principle is the same. An elementary module that you simply cannot do without.
How do you understand that the rubber cuff of the rear axle gearbox of the “seven” needs to be replaced?
Recognizing the wear of the rear axle gearbox seal can, by and large, be done only visually and tactilely - by smudges (precisely smudges, not fogging) of oil on the gearbox in the place where the rubber cuff is located. However, as practice shows, a fairly small number of car owners notice such a breakdown in a timely manner (before the oil completely drains out of the gearbox), therefore, most likely, minor vibrations and/or a strong hum in the VAZ 2107 rear axle gearbox will need to be replaced. rear of the car while driving.
Be that as it may, if you find oil leaks on the gearbox, do not rush to immediately go to the oil seal; in addition, a poorly tightened drain plug can lead to oil leakage, so first of all you should check its condition, and a clogged breather. You will be alerted to the latest breakdown by replacing the rubber seal of the rear axle gearbox too often. However, in order not to wait for these replacements and, accordingly, waste money, we recommend checking the breather for functionality even before starting to deal with the oil seal, so that if necessary, clean or replace it at the same time as the cuff.
This is quite simple to do: grab the breather, or rather its cover, as shown in the photo, press and rotate it in different directions. This should come out easily, without any jamming, otherwise the breather also needs to be replaced. If the cover moves easily, but oil in the oil seal area still oozes, remove the breather (to do this, twist the thread indicated by the arrow in photo 2 with a wrench) and thoroughly rinse it with carburetor cleaning liquid or gasoline, and then blow it with compressed air. Reinstall the removed element, run the repair for 30 kilometers, and then check the rear axle gearbox again for leaks. If it occurs, change the oil seal, and if such a replacement happens again soon, change the breather.
Breather in gearbox
The gearbox must convert the torque in the engine and also change the traction force. It often happens that the gearbox starts to work poorly due to the fact that the gearbox breather is clogged. To avoid any damage, you should clean not only the breather in the engine, but also all the others that are installed in different parts of the machine.
In the gearbox, the breather is located on the gearbox housing cover. Sand or dirt getting into the breather will cause the wheel mounted on the secondary shaft to jam. As a result, wear of bearings and synchronizers increases. It is necessary to wash the breather during each technical inspection, or even more often. If the valve is clogged, the pressure in the gearbox will increase, which will lead to oil leakage through the seals.
How to replace the rear axle gearbox seal of a VAZ 2107 with your own hands: step-by-step instructions.
- Secure the driveshaft using a screwdriver/spade identical to the photo and remove the 4 bolts securing the driveshaft.
- Carefully hang the disconnected shaft, for example, on a rope to the muffler.
- Determine the moment of resistance to turning the drive gear (it will help you avoid making mistakes during assembly), this can be done in different ways.
Method No. 1 - the most accurate - involves using a torque wrench or a dynamometer and a rope.
If using the latter tools, wind the rope around the flange a couple of turns, as shown in the photo, and attach a dynamometer to its free end. Then start winding the rope, gradually pulling back the device. As soon as the flange begins to rotate with the rope, pay attention to the readings of the device and write them down. After replacing the oil seal and installing everything in its place, this figure should remain unchanged.
If you have chosen a torque wrench as an assistant, make sure that its measurement range (scale) is at least 147 Ncm (15 kgfcm), and start tightening the flange mounting nut with it. The force that you need to move it from its place is the required moment of resistance.
Method No. 2 is useful for those who do not have any measuring equipment at hand, but have a colored marker. All you need to do is make 2 marks with it: the first on the nut, the second on the flange itself - as shown in the photo.
Pay attention to the mark on the nut - it should be made exactly on top, and not on the edges, otherwise it may simply be erased when unscrewing.
- Using a wrench and a socket, unscrew the central fastening nut of the gearbox flange, but first you will have to lock the flange itself. The most convenient way to do this is with a homemade wrench made from a piece of pipe and two bolts (see photo).
Why might oil leak?
First, let's try to understand how to determine the time to replace the oil seal. If you believe the manufacturers, a high-quality cuff should last more than 60-70 thousand kilometers. But is this really so? Of course not. Under conditions of constant load, bad roads, dirt falling on parts, and poor quality oil, the oil seal cannot withstand and needs to be replaced quickly. A visual inspection of the rear axle will help identify the need for replacement. It is clear that for a better inspection it is recommended to put the car in a pit. It is often possible to eliminate a leak from the gearbox by tightening loose fastening bolts or replacing the washers with softer options. In this case, copper washers are considered ideal. Often, instead of a washer, a sealant in the form of a thread or ordinary gel is used on threaded connections.
Sealant for threaded connections
In addition, the cause of an oil leak may be an insufficiently tightened drain or fill plug. Careful attention should also be paid to this. If everything is in order with the plugs, then it would be a good idea to pay attention to the connection of the gearbox to the crankcase.
Connection of the gearbox to the crankcase
If the tightness of this connection is broken, then oil leakage cannot be avoided. In this case, replacing the oil seal on the VAZ 2106 bridge or replacing the axle shaft seal will help. As a rule, any leaking oil seal needs urgent replacement. No other type of repair will help here. Oil seals are inexpensive and it is better to replace them periodically so that no problems arise in the future. It also happens that the cause of the leak is the breather. It is located on the upper side of the car crankcase, on the right side.
Breather cover VAZ 2106
First of all, we check the breather cap to see how freely it moves. If everything is fine with it, then it’s all about the oil seal, which requires replacement. Needless to say, if you delay replacement, the oil level will drop and ultimately lead to tragic consequences. As you know, oil for all parts and components of a car is comparable to the oxygen that a person breathes.
Replacing axle seals on a VAZ 2106
A common reason why the oil seal fails is an increased oil level. Therefore, you must always monitor this and not allow it to increase or decrease.
Video.
An oil leak from the axle gearbox through the drive gear oil seal is like a person with a runny nose. It seems that you are working as always, but this constant dampness under your nose is annoying. The only difference is that a person does not need the fluid flowing from the nose, but at the same time it is constantly produced by the body with a cold. And the bridge desperately needs the oil flowing out of the bridge, but it will not be able to replenish the supply without your help. It’s good that replacing the rear axle gearbox seal on a VAZ 2107 and other models of this series is possible with your own hands.
The principle of operation of the breather in the engine
Today, a breather valve to reduce pressure is very often installed on SUVs. This is due to the fact that the device is suitable for off-road driving. Breathers prevent oil leakage. Heated engine oil expands, causing engine pressure to increase.
The pressure in engines or in other automotive devices must find a way out. This causes oil to leak out through various gaskets and gaps. To prevent oil leakage, breathers are installed.
About the consequences of untimely “treatment”
And just as a runny nose can lead to serious problems in the body, even some kind of meningitis, oil leaking from the bridge can lead to serious “diseases” of the drive axle: overheating and jamming of bearings, scuffing on the surface of the gear teeth of the main pair, their rapid wear, increased noise and other troubles, including jamming of the main gear itself. Therefore, if you discover severe oiling in the area of the drive flange, or, even worse, an oil stain on the ground under the gearbox, you should not delay the “operation”. However, if “well, I can’t go on sick leave right now,” then by regularly monitoring and replenishing the oil level in the gearbox, the car can be operated for some time without any special consequences for the health of the bridge.
A little anatomy
In the last years of its life on the AvtoVAZ assembly line, the classic Zhiguli remained perhaps the only passenger car in the world with a rigid drive axle. This design is simple and technologically advanced in production, but has serious disadvantages in operation:
- large unsprung mass of the bridge, which negatively affects the smoothness of the vehicle;
- tendency to steer when one of the wheels hits an obstacle - at this time, due to the misalignment of the bridge, both wheels tilt from the vertical and tend to roll in the direction of the tilt;
- reduction in the useful volume of the trunk, because there must be free space between the axle and the car body for the axle to move during the compression of the suspension.
The advantage of a rigid axle, in addition to manufacturability, is its better adaptability to bad roads: the ground clearance under the axle practically does not change depending on the load, and the wheel drive is reliably protected from external influences by the axle housing.
The Zhiguli bridge consists of a stamped-welded bridge beam (such beams are called “Banjo” for their characteristic shape), a main gearbox with a differential, and axle shafts. The gearbox is made in a separate open housing, the flange of which is bolted to the crankcase. A drive gear with a driveshaft mounting flange and a differential with a driven wheel are mounted in the housing on bevel bearings. The main gears are hypoid, that is, their axes are located at an angle of 90 degrees to each other, but do not intersect (they are crossed). The amount by which the axis of the drive gear is offset relative to the axis of the driven gear is called hypoid offset. Such a transmission, if it is precisely manufactured and well adjusted, operates smoothly and with the least noise, but due to the intense sliding of the curved teeth, it is very sensitive to the quality and quantity of oil in the bridge.
The design of the bridge is relatively simple and technologically advanced, although it is not without its drawbacks
Design and principle of operation
The rear axle of the VAZ 2107 consists of two parts: a driveshaft and a rear axle with a gearbox. Cardan – consists of two axle shafts with a movable joint. It is located under the bottom, along the entire body, from the gearbox to the gearbox. It rotates together with the gearbox gears, and when the rear axle moves up or down, the cardan also changes its position in order to ensure further rotation of the rear wheels.
Gearbox - consists of a metal casing in which two gears are located. One of them is located at the end of the driveshaft, perpendicular to the second, located on the rear axle beam. They have a diagonal cross-section, which allows them to come into contact with each other, thereby ensuring the transmission of rotation.
Since a gearbox is a device in which parts constantly move and, accordingly, heat up, it must have a liquid inside it that provides lubrication of the rubbing parts and removes heat from them. Typically, this fluid lasts for quite a long time, and is replaced very rarely. This stability of the beneficial properties of the oil is ensured by maintaining the correct atmospheric pressure inside the rear axle gearbox, which is provided by the “breather”.
Gearbox for rear-wheel drive models
The “breather” consists of two parts: a glass, inside of which there is an elastic balloon. It is he who connects the gearbox to the crankcase.
In addition to the two main gears, the gearbox includes two pulleys responsible for rotating the left and right rear wheels. At this point, the structure and operating principle of the rear axle are completed.
Can't you spoil the porridge with oil?
Oil is poured into the axle housing up to the lower edge of the filler hole, in the position when the axle is installed and secured to the vehicle. You should not fill oil above this level, since a larger volume significantly increases power loss when the gears rotate and provokes leaks.
Lubrication of gearbox parts occurs as follows. The lower part of the driven wheel and differential are constantly immersed in an oil bath. When the car moves, they rotate, alternately wetting with oil all the teeth of the main gear and differential gears. The differential bearings and the rear pinion bearing are lubricated in the same way. In addition, the teeth of the driven wheel spray oil abundantly, creating “oil mist” in the crankcase. The least amount of oil when splashed goes to the front, most distant, bearing of the drive gear. To lubricate it, a channel is made in the upper part of the crankcase, where, under the influence of centrifugal force, oil is thrown from the outer circumference of the driven wheel. The higher the rotation speed, the more oil enters the channel. This channel leads into the cavity between the bearings of the drive gear, passes through the bearings and returns to the bridge beam. To drain oil from the flange side of the drive gear, there is an oil drain channel in the crankcase. The bearings, due to the conical shape of the rollers, have a pronounced pumping effect, so the flow of oil that flows from the front bearing directly to the oil seal can be quite significant - more than one liter per minute. It is not easy to withstand such pressure, so an oil-removing washer is installed immediately behind the bearing, in front of the oil seal. It slows down the flow rate, but there is still a gap between it and the crankcase through which the oil flows to the oil seal. Therefore, the tightness of the drive gear oil seal is a constant concern for axle designers and manufacturers.
Checking the oil in the gearbox
For the rear axle gearbox of the “seven”, semi-synthetics with viscosity parameters 75W-90 are suitable, for example:
- CASTROL Syntrans Transaxle 75W-90 API GL-4;
- "Lukoil 80W90 GL-5" and others.
1.35 liters of oil is poured through a special filler hole on the gearbox housing. If you need to drain the used oil, there is a drain hole in the bottom of the gearbox for this purpose. Before draining the old oil, it is recommended to warm up the car, place it on a flat surface and jack up the right side of the car . If there are metal shavings in the waste, you should rinse the gearbox container with a special liquid or spindle oil.
It is convenient to fill in new oil using a special syringe, which can be purchased at a car store. Both plugs (drain and filler) should be securely tightened, and then check the condition of the breather, which should move freely. If the breather jams, the contact of the container with the atmosphere will be disrupted, which will lead to an increase in internal pressure, damage to the seals and oil leakage. The oil level in the rear axle gearbox is considered normal when the liquid reaches the lower edge of the filler hole.
Video: changing the oil in the gearbox yourself
Repairing and adjusting the most critical components of the rear axle, as a rule, requires some practice, so it is best to perform it under the guidance of an experienced specialist. If you hear extraneous sounds from the rear axle while driving, you should immediately determine the cause of their occurrence. By ignoring such noises, you can “start” a breakdown and subsequently face complex and expensive repairs. Following simple rules for operating and maintaining the rear axle will extend the life of the vehicle for many years.
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Surgery or therapy?
So, our “wounded” axle is leaking oil around the drive gear flange, and we are ready to save it. But first, as is usual with serious doctors, you need to figure out the cause of the “disease.” How does an appointment with a local therapist usually begin? Of course, from measuring temperature and pressure. You may be surprised, but when starting to repair a bridge, we should also remember these physical characteristics. And that's why. During operation, the drive axle gets quite hot - the temperature in the crankcase can reach 80 degrees Celsius. And since, ideally, the axle housing is a sealed container, along with heating in a confined space, the pressure also increases. This is the law of physics. The increased pressure additionally loads all the seals and gaskets of the bridge, breaking out where, for some reason, there is less resistance. This is often the drive gear seal, which is subject to the most intense friction. To reduce pressure, a valve (breather) is installed on the axle housing, which releases excess pressure. Therefore, the first thing you need to start diagnosing a leak is by checking the functionality and cleaning the breather from dirt. The valve cap should rotate freely. When you lightly press the cap from above, it should move freely and return to its original state when the load is removed.
If cleaning the breather does not help, and the leak continues, it’s time to prepare “surgical instruments”. In our case, a regular plumbing kit will be enough, although it would be nice to grab another skein of thread and a hand balance scale (dynamometer) with a good scale.
What is an engine breather and why is it needed?
Everyone knows that the internal combustion engine, the same one that is installed under the hood of your car, does not run on gasoline, diesel or gas, but on their mixture with air. Moreover, it is air, which costs nothing (unlike fuel, for which we regularly pay a tidy sum at the gas station), that is required many times more. But in addition to the influx of clean air and the removal of exhaust gases through the exhaust pipe, parasitic gases are formed during the operation of the internal combustion engine.
A breather is nothing more than a breathing valve that constantly relieves excess pressure that forms inside the engine during operation. The need for this simple, relatively inexpensive part is difficult to overestimate.
Tell me, doctor, is there any way to do without surgery?
First of all, you need to drain the oil from the bridge. To do this, we turn out both plugs - both the drain and the filler. Next, disconnect the driveshaft from the bridge. When separating the axle and cardan flanges, be careful - sometimes oil accumulates in the cavity between the flanges. If this happens, then check the axial play of the flange by rocking it along the axis with your hand. There shouldn't be any play. If there is noticeable movement (in fact, play of more than 0.05 mm is already very harmful for the bridge), it is worth once again carefully inspecting the traces of oil on the crankcase. Perhaps the oil leaked not through the cuff, but through the gaps in the splines of the loose flange? In this case, it is worth trying to eliminate the play and observe the bridge in operation. If the leak stops, then that was the reason.
Axial play of the flange is eliminated by tightening the nut. When handling a flange nut, you should always remember that it does more than just hold the flange. This is the most important element in adjusting the drive gear bearings, and improper tightening can have serious consequences, ranging from noise to axle jamming. Having inserted two bolts into the holes of the flange, we insert the mounting between them so that, holding it, we prevent the rotation of the flange when the nut rotates. Pull the nut just enough to select the gap. The thread pitch is 1.25 mm, which means that when you turn the nut one turn, it will move along the axis by the same 1.25 mm. If the flange play is minimal - 0.05 mm, then it is enough to turn the nut 1/25 of a turn, that is, only 15 degrees.
Overtightening the nut loads the drive gear bearings with a large axial force, as a result they overheat and may fail. To be sure that we did everything correctly, we need to measure the moment of resistance to rotation of the drive gear. To do this, you need to remove the rear wheels and brake drums, unscrew the axle shaft mounting bolts and pull off the axle shafts, disengaging them from the differential gears. Then we tightly wind the thread onto the flange shaft and pull its free end with a steelyard, measuring the force at which the flange rotates evenly without jerking or acceleration. A less accurate result is obtained by another method, when the steelyard is hooked to a hole in the flange and also pulled evenly. In this case, care must be taken to ensure that the force is directed perpendicular to the radius of the flange circumference. You can also use a torque wrench, evenly rotating the drive gear shaft by the nut, but with such a movement it is difficult to follow its readings. We multiply the measured force value by the radius value, thereby obtaining the moment of resistance to rotation. The torque value should be in the range of 6–9 kgf.cm.
Torque wrenches usually have a scale marked in Newton meters (N.m). One kilogram-force per centimeter (1 kgf.cm) is equal to 0.098 newton meters, or approximately 0.1 N.m.
You can try to do without removing the axle shafts and measuring the torque on the flange. Experienced mechanics can do this. To do this, tighten the nut exactly until the play is eliminated and a little more. After this, we put the driveshaft in place and make a test drive in a mode sufficient for the bridge to warm up to operating temperatures (several tens of kilometers along a country road). After this, we check by hand the heating of the axle housing in the area of the drive gear bearings. If the hand tolerates heat, then we assume that everything is in order. If the bearings have become so hot that a drop of water on the crankcase hisses, then we have overdone it and now we definitely cannot do without a good adjustment. You cannot reduce the moment of resistance to rotation of the drive gear simply by loosening the nut. The fact is that a deformable spacer sleeve is installed between the bearings, which, when the nut is tightened, gives the structure the necessary rigidity. By tightening the nut, we compressed the bushing more than necessary, and it will no longer be able to lengthen back. When we loosen the nut, the bushing is no longer “spacer”, so it needs to be replaced. You should also pay attention to the bearings. If a blue color appears on the rolling surfaces, it means they have overheated and also require replacement.
Rear axle repair
Any repair of the rear axle, as a rule, is quite complex and expensive, so before starting it, you should conduct a thorough diagnosis and make sure that the reason for the malfunction of the car lies here. If, when driving a vehicle, extraneous noises appear that were not there before, you need to try to determine at what moment they appear . If the rear axle makes a hum both under load (when driving with the gearbox engaged) and without it (at neutral speed), then most likely this is not the problem. But when the noise is heard only under load, you need to deal with the rear axle.
To repair various rear axle components you will need:
- a set of open-end and ring wrenches;
- chisel and drift;
- bearing puller;
- hammer;
- center punch or simple pencil;
- torque wrench;
- set of probes;
- calipers;
- container for draining oil.
Shank bearing
The bearing used in the gearbox shank has:
- marking 7807;
- internal diameter - 35mm;
- outer diameter - 73mm;
- width - 27mm;
- weight - 0.54 kg.
To replace the gearbox shank bearing:
- Prepare a hammer, a flat-head screwdriver, a chisel, a puller and wrenches 17 and 10.
Installing a new bearing is carried out in reverse order.
Axle bearing
On the axle shafts of the rear axle of the VAZ 2107, the bearing 6306 2RS FLT 6306 RS is used, the parameters of which are:
- internal diameter - 30 mm;
- outer diameter - 72 mm;
- width - 19 mm;
- weight - 0.346 kg.
When starting to replace the axle bearing, you should additionally prepare:
- jack;
- supports (for example, logs or bricks);
- wheel stops;
- wheel wrench;
- reverse hammer;
- keys for 8 and 12;
- socket wrench 17;
- slotted screwdriver;
- grinder;
- wooden block;
- lubricant, rags.
To replace the bearing you will need:
- Remove the wheel by securing the car with wheel chocks, loosening the fastening bolts with a wheel wrench, lifting the body with a jack and placing supports under it.
After this you need:
- Prepare a new bearing for installation by lubricating it with grease or lithol. Lubricant should also be applied to the axle shaft. Install the bearing into place using a hammer and a piece of pipe.
Installation of the axle shaft is performed in the reverse order. After installing the axle shaft in place, you should rotate the wheel and make sure that there is no play or extraneous noise during rotation.
Shank seal leak
If an oil leak appears on the gearbox shank, you will most likely have to change the oil seal. To replace the shank oil seal you must:
- Disconnect the cardan shaft from the shank and move it to the side.
Shank play
To measure shank play:
- Lower yourself into the inspection hole and turn the driveshaft clockwise (or counterclockwise) until it stops.
- In this position, make marks on the flange and shaft.
- Turn the shaft all the way in the opposite direction and also make marks. The distance between the first and second marks represents the backlash of the shank.
A gap of 2–3 mm is considered normal . If the size of the play approaches 10 mm, measures should be taken to eliminate it. The reason for the increased play is wear of the teeth of the main gear and differential gears, as well as defective bearings, so lateral play is usually eliminated by replacing worn or damaged parts.
In addition to radial play, there may be longitudinal play in the shank, which also causes a hum when the car is moving. If oil appears on the neck of the gearbox, this may be the first sign of an increase in longitudinal (or axial) play. This type of play appears, as a rule, due to:
- “sagging” of the spacer sleeve when tightening the central nut, as a result of which the engagement of the gears is disrupted, the contact patch shifts and a hum occurs when the machine moves;
- deformation of the oil slinger ring made of too soft material.
Underpressed or damaged bearings, as well as worn gears, are also causes of axial play.
If the teeth (or even one of them) of the main gear gears have cracks, breaks or other defects, this pair needs to be replaced. The main pair is also subject to rejection, upon examination of which you can notice the unevenness of the band at the top of the tooth or its narrowing in the middle part. Replacement of the differential box is required if its journal “sags” when the bearings move in and out by hand.
After repairs involving the replacement of worn and damaged parts, it is important to accurately select the adjusting rings when assembling the shank: at the factory, such rings are installed using a special machine until a minimum noise level is achieved. It is also recommended to change the spacer sleeve every time the gearbox is disassembled. It should be remembered that adjusting the rear axle gearbox requires certain skills and if this is being done for the first time, it is better to have a consultant on hand in the person of an experienced car mechanic.
Video: we measure the shank play ourselves
Let's go to the store
So we did everything we could, but the leak didn't stop. This means it's time to change the seal. Actually, according to GOST, these products are called “Reinforced rubber cuffs for shafts.” Or simply - cuffs. If a store offers you a part with that name, don’t be surprised. Factory part designation: 2101–2402052. Further, its variations can be written through a dash: -01, -02 and so on. All of these products are interchangeable and differ in the nuances of their design and manufacturer. Perhaps the most important thing when choosing an oil seal is the manufacturer. Choose products from well-known factories. No name details, in principle, should not attract your attention, because not only according to ours, but also according to Western standards, the cuff must be marked with the manufacturer’s trademark, cuff size, and type of material. Domestic GOST also provides for marking the year of manufacture. As a rule, these are two digits of the year when the mold was made, and next to them are dots, each of which indicates one year of operation of this equipment. You count the points, add their number with the numbers and find out in what year your part was manufactured. The year of manufacture is important because over time, any rubber compound “ages”, losing its shape and elasticity .
The type of mixture from which the oil seal is made is also important. The most expensive and most durable is fluorine rubber. It works well in aggressive environments and at high temperatures. It is usually marked with the Latin letters FBR. Nitrile butadiene rubber (NBR) is considered optimal in terms of price and quality for automobile transmissions. ACM acrylate polymer seals are also available, but they are usually used in components that should not be directly exposed to water. Chemists are constantly improving their products, so the fundamental differences between mixtures are becoming less and less, due to additives introduced into them that improve the weaknesses of certain recipes. Read reviews on the Internet, listen to the seller’s recommendations and make a decision based on your financial capabilities.
When examining externally, first of all pay attention to the quality of the working edge: it should be even and smooth around the entire circumference. You can use a magnifying glass. It will be a big plus for the gearbox seal to have an external boot - like a second edge, but without a spring and with a hole of a slightly larger diameter. The boot, as the name suggests, protects the work area from dust and dirt. The presence of an inclined notch on the boot or near the working edge indicates that the oil seal is designed for shafts rotating in the same direction.
Cleaning the breather. Emulsion. And a little chat :)
Hi all. It all started with the fact that yesterday morning I didn’t start, dropped the Akum, and basically went crazy :( I had to go to work by trolleybus in a hurry. Yesterday morning it was -16, and today it’s already +3, what a winter it is. What we have - I tried in the morning started on gas, picked up the engine, ran for a bit and stalled :( I drove all the gas with the starter, switched to gasoline, pumped it up with a gas pump, tried to start - no luck, it seizes and immediately stalls. Again I drove all the gasoline out of the float chamber, boiled the kettle, poured it on the gearbox , defrosted it - tried to start it - no, it didn't work anymore, I turned it on until the battery barely started turning, there was no time to wait. I left everything like that, locked the car and went to work. It was only in the evening that I figured out what I needed when the car stalled on gas, boil a kettle and pour boiling water on the gearbox, maybe then it would have started without problems. But again the dipstick would have squeezed out 100%, so it’s good that it didn’t start after all.
On the way home from work I stopped at my father-in-law's for some charge, came home and started it on gas, in the evening it was already -5. But another problem appeared - by the way, the same situation happened in the morning - the engine starts and literally after 20-30 seconds of operation the oil dipstick squeezes out. I took off the carb cover - and the hole from the breather was all in emulsion, and frozen :(
The polystyrene foam saved us from the snow - snow fell and covered the entire engine, it was fun to poke around under the snow.
After that I decided to check the hose itself going from the breather to the pan, it was oak - like it was made of plastic, I tried to remove it and it broke :(
“Quiet, the operation is underway!” or Replacing the rear axle gearbox seal on a VAZ 2107
The sequence of work when replacing the gearbox seal is as follows:
- We measure and record the moment of resistance to rotation of the flange (the axle shafts must be removed!) .
- Unscrew the flange nut.
- Remove the flange from the shaft splines.
- Using expansion pliers, remove the oil seal. If you don't have pliers, you can pry it off with a screwdriver. Be careful not to damage the surface of the socket.
- We inspect the flange. If its surface has a pronounced groove in the place where the working edge of the oil seal rubbed, then before installing the new oil seal, insert a washer 1 mm thick into the socket. If the flange is damaged on the working surface, replace it with a new one.
- Lubricate the outer surface of the oil seal with lithol and carefully drive it into the crankcase socket using a mandrel of suitable diameter. If there is no mandrel, press in the oil seal by evenly tapping the end along the circumference of the outer diameter. Make sure that there are no distortions - the working edge should be strictly perpendicular to the shaft axis.
- We inspect the lead-in chamfer on the flange. It should not have defects that could damage the working edge. We install the flange, avoiding sudden movements and impacts, so as not to knock the spring off the oil seal. Before installation, you can lubricate the flange chamfer with transmission oil to make the process easier.
- We tighten the nut, periodically checking the moment of resistance to rotation of the flange. Remember that at the end of the tightening, the resistance in the bearings increases much more intensely than at the beginning . The moment of resistance to rotation should be 1–2 kgf.cm greater than what we recorded before unscrewing the nut. In any case, if the moment exceeded 9 kgf.cm, and the bearings in the bridge were still old, remove the flange again, take out the inner ring of the bearing and change the spacer sleeve. If the bearings are new (new means they have not traveled a single kilometer, because after a hundred kilometers they can be considered old for adjustment purposes), then the normal moment of resistance to rotation after tightening the nut for them should be in the range of 16–20 kgf. cm. Replacing the rear bearing will affect gear alignment, so please refer to the appropriate manual for this procedure .
To prevent self-loosening, the flange nut has a special plastic insert, which, when crushed against the thread, creates additional resistance both when screwing and unscrewing. As a rule, such nuts can withstand up to ten unscrewings without losing their locking properties. If in doubt, get a new nut.
We reinstall the axle shafts and brake drums, screw on the driveshaft, and fill in the oil. We make a test drive and if everything is in order, we enjoy life, until we suddenly find a treacherous spot under the bridge again...
