External grenade (SHRUS): device, possible malfunctions, repair and replacement

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

On front-wheel drive vehicles, there is such a part in the drive as a CV joint - this is a constant velocity joint. It provides transmission of torque from the transmission to the drive wheels. Motorists call this part "grenade". There are two CV joints in the car. It is external and internal. Let's talk about the outdoor grenade.

Device

For those who just got behind the wheel and bought a front-wheel drive car, this information will be very useful. Often, beginners are practically unfamiliar with the device of the car and cannot correctly diagnose problems. Let's try to fill this gap. An external grenade, or CV joint, is mounted on a half shaft. The element is a shaft with retaining rings that hold the hinges. CV joints work in tough conditions and are equipped with dust boots for protection and durability.

The outer joint is connected to the front wheel through a spline connection. The hub nut holds it on the wheel. At the other end of the axle shaft there is an internal hinge, which is fixed to the gearbox and is located ingeared with differential.

As for the CV joint itself, most front-wheel drive cars use the so-called Rceppa joint, or a six-ball joint. It has an outer and inner cage with grooves in which the balls go. The device also has a separator. A hinge of this type performs well even at very high speeds and the wheels turned as far as possible in any direction.

There is another type of CV joints. It is more often installed on Japanese and European cars. This is the so-called tripod. In its body, a part in the form of a three-beam star is fixedly installed, on which the rollers are mounted. The hinge receives torque through a fork with spherical channels in which the rollers move. This design is good from all sides, but the only drawback is the small angle of change of the axis of rotation. But the very possibility of axial movement allows using the tripod as a constant velocity joint.

The inner CV joint works when the angle of rotation of one of the drive wheels is from 10 to 30 degrees. The outer grenade is rotated at the same angle when moving straight. When the driver turns the steering wheel and the car turns, the outer joint angle rises up to 60 degrees. When the car moves over bumps, the distance from the outer CV joint to the inner one is almost constantly changing. The axle shaft, located between the two hinges, is fixed so that when the distance changes, the shaft moves in or out. Half shafts, where on the one hand there is a “Rceppa” hinge, and on the other - a tripod,expensive to manufacture. Therefore, on budget models, Rzeppa hinges are installed on both sides of the axle shaft.

Typical malfunctions

There is an opinion that the outer grenade is a very reliable and durable element in the whole car. The resource of CV joints can very noticeably exceed the resource of all other elements under normal operating conditions. There are no major problems with the hinges. Usually, all malfunctions are associated with a violation of their normal operation.

As we know, inside the hinge there are balls and channels for them. Under the influence of dust, dirt, water channels and balls wear out intensively. The CV joint is protected by a rubber boot fixed to the axle shaft with special clamps.

Any malfunctions of the constant velocity joints are associated with defects in the anther and ingress of sand, dirt, water into the assembly. This leads to corrosion and intense wear. In this case, a replacement will help. The price of a grenade is different. For example, for the "top ten" it costs about 1100-1300 rubles.

Signs of problems

If the grenade (SHRUS) is faulty, then this can be determined by the characteristic crunch when driving on inverted wheels. The crunch will not be during the direct turn of the steering wheel, but in the process of turning the car in one direction or the other. Also, the sound can be heard at the beginning of the movement, especially with sudden starts.

SHRUS can be considered faulty if it has backlash. This can be felt during the diagnostic process with the wheels suspended. And finally, one morea characteristic feature is jerks during acceleration.

Causes of malfunctions

So, it often happens that there is a defective defective VAZ external grenade on sale (often made in China). It's all about the low quality of the metal. You can also highlight the violation of the installation rules during the replacement process. The CV joint will quickly become unusable if there is not enough or a complete lack of lubrication in it. Lubricant may leak from the assembly if the boot is damaged while the machine is moving.

Often, careless driving on bad roads leads to the failure of the hinges. CV joints do not like bumps and bad bumpy roads. And finally, natural wear can be distinguished when the hinge “dies” on its own due to age.

Diagnosis

First, you should try to determine if the outer grenade is crunchy. The vehicle must be stationary. In turn, pull the axle shaft on each side. If there is a knock, then there is a backlash in the grenade. This hinge needs to be changed. Another method will require dismantling and disassembling the assembly - a malfunction can be detected in this way.

Further, the car must move on a flat road. To find out which hinge is out of order, turn the steering wheel all the way to the right, and then to the left. If there is a crunch after turning to the right, then you need to replace the outer grenade with the right one. If it crunches after turning to the left, then you need to change the left one.

Repair

First you need to get to the grenade. To do this, you need to break the wheel bolts and the hubnut. Then the wheel is removed completely, and then the hub nut is unscrewed. Next, the retaining ring is removed from the shaft. Then the brake caliper. Next, the drive mounting bolts are unscrewed, the ball joint is pressed out. Now you can completely remove the hub and get direct access to the outer grenade. It is removed and disassembled.

If there are signs of wear on the hinge elements, then the grenade changes completely. However, this will not particularly hit your pocket. For example, the price of a grenade for a VAZ is on average 1200 rubles. If there is wear only on the balls, then they are sold separately in car dealerships at low prices. The most important thing is to choose the balls of the right size. If the separator is worn, then the joint can be repaired by replacing the separator or rearranging the CV joint grenade.

In the first option, it is enough to purchase a repair kit for repairs or choose a suitable separator at one of the dismantling sites. The main thing is that the wear of the new part is less. The second way is to swap the CV joints from the right and left axle shafts to the other side. The fact is that the separator has uneven wear. With a different direction of rotation, non-worn parts will work.

Replacement

Not everyone knows how to change the CV joint. It's actually quite easy to change. Instead of the one removed, a new assembly is installed on the axle shaft, stuffed with grease and assembled in the reverse order.