Vehicle operation Skoda Octavia A7 often associated with the need to carry out routine maintenance on the suspension and transmission. One critical procedure is servicing the wheel drives, which transmit torque from the transmission to the drive wheels. If you hear a characteristic cracking sound when turning or vibration on a straight line, the problem may be hidden in the wear of the internal constant velocity joint.
Many owners Octavia they try to ignore the first symptoms, which ultimately leads to expensive repairs of the entire axle shaft or damage to the gearbox. Inner CV joint is responsible for compensating for the axial movements of the axle shaft, and its failure can completely paralyze the movement of the car. In this article, we will look in detail at how to correctly diagnose a malfunction, select the appropriate spare part, and perform the replacement yourself without contacting a dealership.
Diagnostics of internal CV joint faults
It is more difficult to determine wear on the inner joint than on the outer joint, since the symptoms are often masked as problems with the suspension or engine. The main symptom of a malfunction is vibration that occurs during sudden acceleration, especially in high gears. Unlike the outer CV joint, which makes a loud cracking sound when cornering, the inner one can โknockโ or โvibrateโ when accelerating in a straight line.
It is important to pay attention to the nature of the vibration: if it increases with increasing speed and disappears when the gas is released, this is a sure sign of wear on the tripod or the internal joint housing. It is also worth checking for play in the area where the axle shaft connects to the gearbox. Diagnostics should be carried out on a lift or platform to exclude the influence of other suspension units.
- ๐ Conduct a visual inspection of the boot for cracks, tears, or signs of lubricant leakage.
- ๐ง Have an assistant press the gas hard while in gear while the car is stationary (if there is a risk, use jack stands).
- ๐ Pay attention to vibration in the steering wheel, which may indicate imbalance or wear on the drive trains.
โ ๏ธ Attention: Do not confuse vibration from the inner CV joint with wheel imbalance. When unbalanced, vibration is usually constant at certain speeds, and when the CV joint wears out, it manifests itself precisely when transmitting torque under load.
Selection of quality spare parts for Skoda Octavia A7
The auto parts market is full of offers of varying quality, and choosing the right manufacturer for Skoda Octavia A7 - the key to the durability of the repair. Original parts from VAG They are expensive, but provide maximum reliability and service life. However, there are proven alternatives that are not inferior to the original in terms of performance when installed correctly.
When choosing, pay attention to the body material and the quality of the separator. Tripod (three-pin joint) inside must have perfectly smooth raceways. Cheap Chinese analogues often use mild steel, which quickly deforms, leading to jamming of the unit. Avoid purchasing spare parts without packaging and manufacturer's markings.
The table below shows the comparative characteristics of popular brands on the market:
| Brand | Country | Approximate price | Resource (km) |
|---|---|---|---|
| Original VAG | Germany/Poland | High | 150 000+ |
| SNR | France | Average | 120 000 |
| GKN (Loebro) | Germany | Average | 130 000 |
| Third party brands | Various | Low | 40 000 - 60 000 |
- Original VAG
- SNR
- GKN (Loebro)
- Budget analogue
Necessary tools and preparation for work
Before starting work, it is necessary to prepare a specialized tool, since the transmission unit Skoda Octavia A7 requires significant effort to dismantle. A regular set of wrenches will not be enough, especially for unscrewing the hub nut, which is tightened with a large torque. You will need a torque wrench, a circlip puller, and a tool to press out the axle shaft.
Prepare your workplace: the car should be parked on a level surface with the handbrake on. If you're working in a garage, make sure you have access to a lift or secure supports. Security When working with the transmission, it comes first, since the axle shaft weighs a lot and can cause injury if it falls.
- ๐ ๏ธ A set of socket heads (from 10 to 32 mm) and a wrench with an extension.
- โ๏ธ Circlip remover (pliers or special tool).
- ๐จ A hammer and a soft metal drift for knocking out the axle shaft.
โ๏ธ Preparing to replace the inner CV joint
โ ๏ธ Attention: The hub nut is Skoda Octavia A7 has a left or right hand thread depending on the side, but most often it is a standard right hand thread. Use a hammer socket or securely lock the brakes to strip the nut.
Step-by-step instructions for dismantling the axle shaft
The process begins by removing the wheel and unscrewing the hub nut. If you can't get the nut off, try shifting into fifth gear and pressing the brake pedal (while having a helper try to unscrew the nut). After unscrewing the nut, it is necessary to loosen the bolts securing the suspension arm to the steering knuckle to free the hub.
Now you need to disconnect the axle shaft from the gearbox. To do this, use a pry bar to carefully pry up the CV joint housing coming out of the differential. Do this carefully so as not to damage the transmission seal. If the seal leaks, you will have to replace it, which will complicate the repair.
After removing the axle shaft from the gearbox, inspect the condition of the oil seal and seat. Damaged oil seal will lead to rapid loss of oil in the gearbox. Install a plug in the transmission hole to prevent transmission oil from leaking.
What to do if the axle shaft does not come out of the box?
If the axle shaft is stuck, do not hit it directly with a hammer. Use a special puller or gently tap the end of the shaft through a wooden spacer. Sometimes heating the joint area with a hair dryer helps, but be careful not to damage the rubber seals.
Replacement of the internal CV joint and installation of a new unit
After removing the axle shaft, it is necessary to remove the old inner CV joint. To do this, clamp the shaft in a vice and carefully knock out the joint with a hammer through a wooden spacer. Be extremely careful: when removing the old assembly, many small parts fly out of it - a retaining ring, a separator and balls (or rollers). Collect them all.
Clean the shaft of old grease and rust. Put on the new boot and tuck it into the groove of the housing. Fill the inside of the new hinge with special lubricant (usually included in the kit). Make sure the retaining ring is installed correctly and securely locks the assembly to the shaft. It is critical that the snap ring is completely seated in the shaft groove, otherwise the CV joint will fly off while driving.
Reassemble the axle shaft in reverse order, placing the boot in place. Distribute the lubricant evenly inside the boot to prevent it from breaking during operation. After assembling the axle shaft, install it back into the car, connecting it to the differential until the stopper clicks.
Before installing a new boot, be sure to treat the inside with silicone grease. This will prevent the rubber from sticking to the metal and will extend the life of the seal when operating in extreme temperature conditions.
โ ๏ธ Caution: Do not use conventional lithium grease or graphite compounds. For CV joints, a specialized lubricant based on molybdenum disulfide (MoS2) is used, which can withstand high loads and temperatures.
Final assembly and operation check
After installing the axle shaft into the transmission, tighten the hub nut to the recommended torque. For Skoda Octavia A7 this moment is usually about 250 Nm, but it is better to check the service book of the specific modification. Tighten the lever mounting bolts and install the wheel.
Lower the vehicle to the ground and check transmission operation. Start the engine, shift into gear and try driving for short distances. Listen for extraneous sounds and check for vibrations. Leak test The oil is also mandatory - after the trip, examine the joint of the semi-axis and the box for oil stains.
- ๐ Conduct a test drive with different modes: acceleration, braking, coast down.
- ๐ Listen to the sounds when turning the steering wheel left and right.
- ๐ Check the absence of backlashes in the steering after replacement.
A properly installed internal SRUC shall not emit any sound during acceleration and shall not cause vibrations of the steering wheel at speeds above 60 km/h.
Common replacement mistakes and how to avoid them
Many car owners make mistakes that lead to the re-injection of the node. The most common problem is the wrong installation of the locking ring. If it does not snap to the end, the semi-axis can jump out of the differential under sharp braking or acceleration. Always check the fixation "to the touch" before assembly.
Another mistake is using a damaged anther. Even a microcrack will lead to dirt and moisture entering the node, which will kill the new SRUS several thousand kilometers away. Do not try to save on anther or lubricant - these are the components on which the resource of the entire semi-axis depends. Build quality directly affects traffic safety.
It is also important not to drag the bolts of the suspension levers attachment to the wheel installation, as this can lead to deformation of the rubber bushings. Puff all suspension elements produce only after the car is on wheels and has weight on the suspension.
Is it possible to replace only the inner CV joint boot?
Theoretically, it is possible if the hinge does not yet have backlashes and wear of tracks. However, in practice, if the anther has broken long ago, dirt has already got inside, and the SRUS is already worn out. It is better to replace the entire unit to avoid re-repairing after a short time.
Questions and answers on the replacement of the SRUS
How long does it take to replace an inner CV joint?
With the right tool and experience, replacing one internal SRUS takes 1.5 to 3 hours. If youโre doing it for the first time, spend more time exploring the nuances and finding the tool.
Do I need to change both SWATs at the same time?
No, it is not necessary to change both SRUSs at the same time if the second is in perfect condition. However, if the mileage of the car is large, it makes sense to inspect the second drive and, if there are the slightest signs of wear, replace it preventively.
Can I go if the anther of the inner SRUS has broken?
In the short term, yes, but donโt delay. The dust protects the hinge from dirt. Without it, the hinge will quickly fail, which can lead to a jamming of the wheel while driving, which is extremely dangerous.
Which lubricant is best for Skoda CV joints?
It is recommended to use the original VAG lubricant or molybdenum disulfide (MoS2)-based analogues such as GKN, Loebro or SNR. Avoid universal lubricants that are not designed for hinges of equal angular speeds.