Not a single shaft in a car can work on its own, it needs elements that transmit torque to other components of a complex mechanism, and crankshaft pulley is one of such links in a number of many transmissions. As with many other parts, this one also needs to be handled, removed in time, and replaced if necessary.

Where is the crankshaft pulley and how to get to it?

When you lift the hood and take a look at the engine, the crankshaft damper pulley (as well as the normal one) is almost invisible. It is hidden by the generator, however, looking down to where the belt stretches, you can see the disk tightly fixed on the shaft by the hub. This is the detail you are looking for. There are two types of pulleys, conventional and with a damper, and the latter option is distinguished by the presence of an external massive ring, separated from the main part by a rubber gasket, to reduce the vibration of the part. The teeth necessary for operation are cut along the outer edge of the damper.

To remove the pulley, you must first release the locking bolt on the generator, then loosen the tensioner in order to slightly release the belt and be able to remove it. Disconnect the antifreeze tank. The power steering belt can also interfere, so aside from the pulley we find and unscrew the 14 bolt, which creates tension in the power steering transmission, after which we remove the latter. There remains the final step that separates us from success, and the most difficult one is to unscrew one more single bolt, which fixes the pulley. You can only find the fastener by looking under the car under the right front wheel, and if you have a pneumatic wrench, the operation will be done without difficulty.

Why is it difficult to remove the crankshaft sprocket?

In the absence of a special tool, remove the bolt holding the toothed pulley crankshaft, is very problematic, since the thread is cut so that the direction of unscrewing coincides with the torque of the shaft when the engine is running. However, this is precisely the way out. You only need a long wrench with a 19 head (can be extended with a pipe cut), which rests on the ground against the rotation of the shaft. We carry out small preparatory work- we put wedges under the front wheels, and disconnect the connector on the ignition coil. What for? To use the starter as a mechanical force applied to the bolt.

So, we did everything so that the car does not accidentally start and does not move away, now we ask everyone present to move away, and we ourselves climb into the cab (do not leave your legs sticking out) and sharply, but briefly, turn the key to start. In case of an unsuccessful attempt, do not despair and repeat. Usually from the second time, less often from 5-6 approaches, the bolt turns. Now you can proceed to the next event - removing the pulley hub from the shaft, given that it sits tightly and is held by a key. When you need to tighten the bolt back, you either need to put a lot of effort into tightening it, or still find an air wrench by then.

Even if the crankshaft pulley bolt is removed, there is a lot of work ahead

So, you finally managed to remove the stubborn crankshaft pulley bolt using a starter or pneumatic tool. However, this does not mean that in a second the desired part will be in your hands. The fact is that the hub sits very tightly on the shaft, in addition, a key keeps it from accidental slipping. Perfect option- use a special puller, you can even the cheapest one, made in China, the paws of this tool will save you from using extra effort and wasting time. Alternatively, an aerosol lubricant, such as WD-40, is injected, after which the crankshaft pulley hub gently swings with thrust towards itself.

The pulley must be removed carefully so as not to damage the keyway, otherwise the part will not fit tightly, which will lead to rapid wear of the hub.

Another method most often used by drivers is to remove the pulley by prying it around the circumference with a crowbar. If a regular car is too big, use a motorcycle hardened L-shaped tool. In any case, the operation will require a lot of strength, so it is advisable that you have an assistant. It is better to put on a new pulley by smearing with something viscous, for example grease, the place where the key fits (we tilt it slightly towards the impending hub), then we tap the pulley with a hammer through a soft gasket made of thin rubber.

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Locksmith and mechanical assembly works

Flexible gears and assembly of pulleys

Belt drives are divided into two main groups: flat belt drives and V-belt drives. Flat-belt gears are also divided into two groups: ordinary gears and gears with a tensioner.

Ordinary transmissions are divided into three types: open, cross and semi-cross. Open gear is used with parallel shafts. The parallel arrangement of the shafts is the simplest and most convenient for the belt drive device and favorable for the operation of the belt. A pulley is put on each of the shafts, through which the belt is thrown. In this case, both pulleys rotate in the same direction.

If the direction of rotation of the pulley coincides with the direction of movement of the clockwise, then they say that the pulley rotates clockwise, if it does not match, then the pulley rotates counterclockwise.

In each pair of pulleys connected by a belt drive, a distinction is made between driving and driven pulleys. The pulley that receives movement from its shaft and transmits it to the belt is called the drive pulley, and the pulley that receives movement from the belt and transmits it to the shaft is called the driven pulley.

On fig. 1a shows an open belt drive. Pulley Ox is leading. The arrow in the figure indicates that it rotates clockwise. Driven pulley 02 will also rotate clockwise.

If you need to get the rotation of the driven pulley in the direction opposite to the rotation of the driving pulley, then use a cross transmission (Fig. 1, b). In this case, the drive pulley 01 rotates clockwise, and the driven pulley 02 will rotate counterclockwise. The shafts are parallel to each other.

If the shafts are perpendicular to each other, then a semi-cross gear is used (Fig. 1, c).

Rice. 1. Types of belt drives: a - open, b - cross, c - semi-cross, d - cross section of the V-belt, d - rotation transmission scheme, c - cross section of the V-ribbed belt

In machine drives, flat belts are used - leather, cotton seamless, cotton sewn, woven and rubberized and wedge-shaped. The machines are mainly used leather, rubberized and wedge-shaped. On fig. 1d shows a section of a V-belt: it consists of several rows of rubberized fabric, several rows of cord (thick twisted cotton threads), a rubber layer and a rubberized fabric wrap.

On fig. 1, e shows a V-belt drive. Each of the belts is placed in its own groove on the pulley rim. In this case, the belt is sunk into the groove so much that it does not touch its bottom with its lower surface.

Poly-V-belts have gained distribution fig. 1, e. These are endless flat belts, on the inner surface of which there are wedge protrusions made in the form of wedge-shaped belts (their number is from 2 to 36). These protrusions are included in the corresponding depressions of the pulleys.

The main disadvantage of a belt drive is the slippage of the belt, which depends on the tension of the belt and the amount of arc in which the belt covers the pulleys. With different pulley diameters, the smaller pulley, which has a small amount of belt coverage, is in the worst position.

To increase the belt tension and the amount of coverage for smaller pulleys, tension rollers are used (Fig. 2, a). The diameter of the tension roller is taken equal to 0.8 - 1.0 of the diameter of the small pulley. It is located on the driven branch at the small pulley. Due to the gravity of the roller, and, if necessary, an additional load or spring, a constant tension of the belt is carried out. This provides a large angle of coverage of the pulley by the belt, improves the working conditions of the transmission, and allows to reduce the center distance.

In all types of belt drives, a tension shaft is used. Belt tension is performed periodically by moving one of the shafts (Fig. 2, b, c).

Belt tension methods:
- an electric motor with a small pulley is mounted on a sled and can move along them. Tension is performed by a screw; using a swing plate. The plate is hinged, its position is fixed with a screw. The tension is carried out due to the gravity of the motor and plate; with the help of cargo. The load pulls one of the shafts and provides automatic tension control.

Rice. 2. Methods for tensioning belt drives: a - tension roller, b - sled with installed engine, c - gravity force of the electric motor mounted on a swinging plate

The first two methods are used in all types of technological equipment for any belt drives. Flat belts are shortened after drawing, followed by stitching and gluing.

Pulley assembly. Pulleys are usually made of cast iron or steel. They are made either with spokes or with a solid disk, in which holes can be made to reduce the weight of the pulley. Pulleys can be solid and split. When the pulley is located at the end of the shaft, solid pulleys are used, and when located between the bearings, split ones are used.

Pulleys are single-stage and multi-stage. A multi-stage pulley has several stages of different diameters.

Pulleys for V-belt transmission differ in design from smooth pulleys only in the presence of prismatic grooves on the rim.

Working one-piece pulleys are mounted on the shaft with a tight or tight fit. If the pulley is installed on the shaft journal protruding from the bearing, then it can be conical (Fig. 3, a) or cylindrical (Fig. 3, b) with a feather key or wedge key. A shoulder is made on a cylindrical shaft with a feather key (Fig. 3, c) to fix the position of the pulley, and so that the pulley does not move during operation, it is additionally fixed with a nut (Fig. 3, d). If the pulley is fastened with a wedge key (Fig. 3, c), then additional fastening is not required.

Installing a pulley on a wedge key is used only in low-speed and non-critical gears, when an exact fit is not required, since the wedge key displaces the hub axis, and with a small length of it, misalignment appears, which is unacceptable in high-speed heavily loaded gears. When using a feather key, the pulley hub axis offset is much smaller and such connections are more accurate.

If you need very high accuracy, spline connections are used - (Fig. 3, d). With this type of connection, the pulleys are centered better than on the keys, strength increases and the landing site wears out less.

Rice. 3. Schemes for assembling pulleys on shafts: a - at the conical end of the shaft, b - at the cylindrical end of the shaft with a key, c - installation of a pulley with fastening with a wedge key, d - landing of a pulley on a splined shaft; 1 - shaft, 2 - key, 3 - locking screw

To fit the pulley on the shaft, screw devices are used, for example, clamps. A detachable clamp (Fig. 4) is put on the shaft and abuts against its collar. Then, traction is passed between the pulley spokes, and a bar is placed against the end of the pulley hub, against which the screw rests. By turning the screw and lightly striking through the lining in different places on the outer surface of the hub, the pulley is gradually pushed onto the shaft. Impacts eliminate the pulley jamming on the shaft due to possible distortions.

Split pulleys can be installed anywhere along the length of the shaft. The assembly of the pulley consists in connecting its two halves with studs. Checking the correct fit of the pulleys on the shaft is reduced to checking for runout.

The runout of the pulleys causes rapid wear of the bearings, and in the gears of precision high-speed metal-cutting machines it contributes to an increase in vibrations that increase the surface roughness of the workpieces. The reasons for the runout of the pulleys are: shaft bending, improper machining of the pulleys and improper fit on the shaft during assembly.

Rice. 4. Scheme of landing a pulley using a clamping bracket a - for runout, b - mutual parallelism of the shafts using a cord with weights, c - a metal ruler, d - a cord; I - arrows, 2 - weight, 3 - pulleys

Rice. 5. Schemes for checking the assembled pulley:

The runout of the pulleys is checked with a thickness gauge or indicator. When checking the beat with an indicator, the reading is carried out according to the dial of the indicator (Fig. 5, a), and when checking with a scriber, the amount of beat is determined with a probe.

Check two parallel shafts using arrows and a plumb line (Fig. 5.6). Arrows are fixed at the ends of the shafts, the ends of which are in contact with the cord. When the shafts are rotated 180°, the arrows must again come into contact with the cord. The check is also performed using a ruler - fig. 5, c, with the help of a cord - fig. 5, d (when pulling the cord between the rims of the pulleys and the cord, there must be the same gap).

After checking for runout, put on the belt. To do this, the pulleys are rotated manually. First, the belt is put on the drive pulley, then on the driven. For putting on, use hooks or tips.

Someday, every motorist who is used to doing everything with his own hands is faced with the need to dismantle the crankshaft pulley. Most often this is due to the replacement of sealing glands, which eventually age, crack and begin to leak oil. For an experienced minder, removing the crankshaft pulley is not particularly difficult, however, as Internet forums show, ordinary motorists who decide to save money often encounter great difficulties here.

This is what the crank pulley looks like

What prevents you from removing the crankshaft pulley?

In the vehicle owner's manual and repair manual, the procedure for dismantling the crankshaft, including the removal of the pulley, is described beautifully and succinctly, and it seems that it is easy to perform. But in reality, everything is not so simple. There are several reasons for this:

1. Inconvenient for work location of the pulley in engine compartment. It is hidden behind the generator and the approach to it is limited by the elements of the body structure. Pulleys are conventional and damper, which have an additional outer ring with a rubber seal to absorb vibration. To get to the pulley mounting elements, you need to loosen the tension bolts and remove the alternator and power steering belts. And even after that, when performing dismantling work, special care must be taken in the application of forces so as not to accidentally damage surrounding nearby parts and body paintwork.
2. When installed at the factory, the crankshaft pulley is clamped with a bolt or nut with a high compression force to ensure a secure fit. During engine operation, the right-hand mounting thread further strengthens the clamp. Heat and environmental influences exacerbate this process over time through oil coking and metal corrosion. As a result, the fastening nut or bolt firmly adheres to the pulley body, and it is not easy to break this adhesion of metals without knowledge of special methods.
3. When the crankshaft rotates freely with any wrench. Therefore, before unscrewing the crankshaft pulley, the issue of reliable fixation of its position should be resolved in order to prevent turning when unscrewing the nut. In workshops, special devices are used for this, which are bolted to the pulley in technological holes and create a reliable stop against turning. In the absence of such devices, this problem can be solved by installing reliable stops under the wheels and setting the 4th speed mechanical box gears. You can also fix the crankshaft flywheel by resting a mount against its teeth or holes.

How to unscrew the crankshaft pulley?

Pulley removal. Unscrew the nut

The pulley can be attached to the end of the crankshaft with a power bolt or nut. The nut is found on most rear-wheel drive cars. She may have special protrusions for engagement with the handle of the "crooked starter", the so-called "ratchet". To break the nut, the masters at the service station use a 36 or 38 socket wrench with a welded long handle and a locking device worn on the pulley. How to unscrew the crankshaft pulley , fixed with a nut, at home? To do this, you can do the following:

• put the car on a "pit" or overpass;
• engage 4th gear to prevent crankshaft turning when unscrewing the nut;
• lift the parking brake handle up to the stop to prevent the wheels from turning and the vehicle moving;
• tap the edges of the fastening nut with a wooden hammer;
• using a socket wrench to fit the nut and a handle extension in the form of a metal pipe, try to move the nut from the sticky position with a sharp counterclockwise movement.

Video: How to unscrew the nut on the wheel pulley and replace the oil seal

If successful, you can, by changing the position of the key head, gradually unscrew the nut to the end. If this attempt was unsuccessful, then the following method can be applied:

• put the gear knob in neutral position;
• remove the caps from the spark plugs to prevent sparking and starting the engine;
• put the head of the key on the nut and rest the end of the lever against the ground or the side member so that the pulley cannot turn to the right;
• by briefly switching on the ignition, give the crankshaft an impulse of rotation. Usually, one or two attempts to start will help the nut come out of place, and then it can be easily unscrewed with a wrench.

On most front-wheel drive vehicles, the pulley is bolted on. Before removing the crankshaft pulley , tightened with a bolt, perform the following operations:

• raise the right side of the car in front and install it on a trestle or stump, dismantle the wheel;
• remove block air filter, protective cover, loosen and remove drive belt generator, remove all parts that prevent free access to the pulley;
• to lock the crankshaft, you need to remove the plug in the clutch housing and insert a pry bar into the hole, resting it on the teeth of the flywheel;
• throwing a wrench head over the bolt, use the lever extension to apply several sharp forces in the direction of left rotation to break the bolt from its initial position. Most attempts succeed. If unsuccessful, you can try the method above for loosening the nut, with a short start of the starter.

The experience of the common people should also be borne in mind, which makes it possible to reduce the adhesion of the nut and bolt to the pulley. If you pre-lubricate the bolt or nut with vinegar essence, brake fluid or WD type grease, they come off easier. there is information about where it is located and how to check the crankshaft sensor.

How to remove the crankshaft pulley

After unscrewing the fastener, you need to remove the pulley. It sits tightly on the hub and is fixed with a key, so it will not be possible to simply pull it off the shaft by hand. It is best to use a special puller for this, which has two paws that capture the edges of the pulley and a central twisting screw stop resting against the shaft axis. In the absence of a puller, you can use mounts for this, with which you need to evenly pry the pulley from opposite sides, applying efforts in the direction from the shaft.

The point of application of force should be chosen as close as possible to the shaft. Before removing the crankshaft pulley, you can gently tap it with a wooden mallet to eliminate possible misalignment. Be especially careful not to deform the locking key and groove. The reverse installation of the pulley on the shaft should be carried out after treating the mounting points with grease, so as not to apply great efforts leading to distortion.

Whatever the car, sooner or later it will have to be repaired. If your car, for example, has a deformed crankshaft pulley, and you need to remove it, then for this you will have to put the "iron horse" on the parking brake, then use a jack to raise the front of the car and install it on special props so that it does not fly off from a jack.

Continuing the procedure, remove front wheel With right side and dismantle the crankcase protection, if any. Then you should remove the drive belt, which is usually intended for auxiliary units. Before dismantling it, be sure to put a small marking on the belt tape, which will indicate the direction of its rotation.

The next step is to loosen the bolt that secures the pulley to completely block it from turning.

Such work is best done with an assistant, since you cannot cope with this problem yourself. Next, ask your assistant to turn on the highest gear and at the same time squeeze the brake pedal all the way. In the case of the AT model, loosen one of the torque converter bolts and try attaching the drive plate to the transmission dome with a regular steel bar and a few suitable bolts with washers.

When the engine is removed from the car, you need to block the flywheel and drive disc. After that, unscrew the fixing bolt and remove the crankshaft pulley from the trunnion. Having removed the VAZ crankshaft pulley, you should check the condition of the oil seal itself. If it is out of order, be sure to replace it.

So, for starters, you should very carefully install the crankshaft pulley on the trunnion. Be sure to ensure that the keyway is correctly seated on the key. Check the completeness of the fit of the pulley itself, without damaging the seal lips. Then screw in a new bolt together with a washer seated on it.

Next, you should block from the possibility of turning using the same method as when removing. After that, tighten the fastening bolt, applying the force of the first stage for this, and tighten it to the corners of stages two and three. It is necessary to use a special goniometric nozzle for this. Alternatively, reference marks can be applied with paint or a quality marker.

After the steps completed, the crankshaft pulley can be considered installed. It remains only to tension the drive belt itself, which is used for auxiliary units, while observing its original direction of rotation. Don't forget to install the crankcase guard, and also screw on the front right wheel that you removed before starting work. Having lowered the car to the ground, that is, having previously removed it from the jack, do not forget to tighten the wheel mount, applying the required efforts for this. Good luck to you, as well as a pleasant and long drive in your car!

Pulley assembly.

Depending on the design of the transmission, pulleys can be located anywhere on the shaft or mounted on its landing end. Split pulleys are installed anywhere on the shaft and assemble without any difficulty. When tightening the two halves of the pulley with bolts, make sure that the pulley split planes are aligned without distortions, displacements and slots. The pre-assembled pulley with a keyway is pushed onto the key laid in the groove of the shaft, then the nuts are tightened first at the hub, and then at the rim.

One-Piece Pulleys more often located on the end of the shaft protruding from the bearings. This end is made conical (Fig. 109, a) or cylindrical (Fig. 109, b), with a prismatic or wedge key. A cylindrical shaft with a parallel key has a shoulder to fix the position of the pulley. A washer is placed on the free end of the shaft end, which is fastened with screws screwed into the shaft end. In precise connections, the pulley groove and key are fitted by scraping. The key should be installed with light blows of a copper hammer or with a clamp.

Rice. 109. Techniques for assembling pulleys and checking the mutual parallelism of the shafts:

a - at the conical end of the shaft, b - at the cylindrical end of the shaft with a key:

1 - shaft, 2 - key, 3 - locking screw; c - landing of a pulley on a splined shaft, d - checking the mutual parallelism of the shafts with weights, d - checking with a metal ruler, e - checking with a cord: 1 - arrow, 2 - pulley, 3 - weight

Taper pulley centering(see Fig. 109, a) gives a better tightness of the hub hole to the shaft neck.

Fitting pulleys on splined shafts(Fig. 109, c) has great advantage before the method described above: better centering, greater strength and less wear of the mating points are obtained.

After installing the pulleys on the shaft, the correct fit is checked, which comes down to checking for runout. Beating is the vibration of the outer surface of the part when it rotates around its axis. The value of the beat of any point on the surface of the part is the largest swing of this point during one revolution of the part.

The runout of the pulleys causes rapid wear of the bearings, and in the gears of precision high-speed metal-cutting machines it contributes to an increase in vibrations, which worsens the surface finish of the workpieces.

For normal operation belt drive, it is necessary that the middle planes of both pulleys coincide, which is possible only if the axes of the driving and driven pulleys are mutually parallel (Fig. 109, d, e, f).

Assembling and testing V-belt pulleys is no different from flat belt pulleys.