Modern car is a complex of complex systems and mechanisms. One of the most important components of any car is the suspension. It is she who provides the connection between the wheels and the car body. There are several suspension schemes, however, if any of them fail, the driver may hear a characteristic knock in the rear wheel while driving. The reasons for this phenomenon may be different. In today's article, we will look at why the rear wheel knocks while driving and what can be done about it.
The banal reason is bolts
Let's start with the simplest. Knocking in the rear wheel of the VAZ during movement can occur corny due to loose bolts. And it is enough to loosen them only a couple of degrees, so that an annoying knock appears. In addition, vibration at the rear of the vehicle may also occur at high speeds.The solution to the problem is simple. Tighten the bolts to eliminate the sound of the rear wheel while driving.
Many owners install discs of other widths and diameters. This has a positive effect on the handling characteristics. However, everything is good in moderation. Choose discs wisely.
Pay attention not only to the diameter, width, bolt pattern, but also to the offset. If the offset of the disk is less than the factory one, the wheel may touch the caliper. As a result, there is a knock in the rear wheel. It is also worth choosing the right width. If the disc and tire are very wide, there is a risk that the wheel will touch the body or suspension elements. A common case is that the tire rubs against the wheel arch. This occurs when hitting any bumps. In this case, you need to replace the tire or roll out the arches.
Rear fender liner
Very often, owners of budget cars install plastic fenders back. They are also called lockers. Since they are not installed on many cars from the factory, the owners mount them on their own and very often with serious errors. As a result, the fender liner can simply move away from the mounts. As a result, there is a knock in the rear wheel when driving, as the locker hits the tire.
A similar situation can happen on a well-fixed locker. But this occurs when the car is heavily loaded. As a result, the distance between the locker and the tire decreases. When hitting a pit, the wheel simply beats againstplastic protection. As soon as the car goes without load, the knock disappears. This indicates an overload or the installation of a wheel that is too large (wrong wheel diameter or high profile rubber), as a result of which the suspension travel is greater than the distance between the tread and part of the fender liner.
This is another reason why there is a knock in the rear wheel when driving. The average shock absorber resource is 60 thousand kilometers, but there may be a large error due to driving style and road conditions. You can identify a worn shock absorber by leaking. There will be oil streaks on the surface of the cylinder. However, this is not always the case. You can also recognize a broken shock absorber by the behavior of the car. The car will jump on the pits and sway at speed. In addition, a knock will be heard in the rear wheel when driving. This sound is amplified on bumps. Since the shock absorber is not repairable, it is replaced entirely with a new one. And it is desirable to change both sides at once. Their resource is approximately the same, therefore, with a high probability, the neighboring shock absorber will require replacement after 3-5 thousand kilometers.
Also, a knock in the rear right wheel when driving can happen due to a broken shock absorber bushing. To check this, just shake the element to the sides. The shock absorber must be securely fastened at the top and bottom. On vehicles such as the Daewoo Nexia, the rear shock absorber at the top is attached to the body through a rubber washer. If it is even a little damaged, they can be publishedvery strong knocks on the bumps. At first, the owner will think that it is time to change the shock absorber. But after replacing it, the problem does not go away. Therefore, it is not always necessary to sentence this element immediately. You must first check the condition of all rubber elements that are involved in the shock absorber mounting.
Over time, the springs sag. However, this is not the only trouble that can happen to them. So, the coils can burst. As a result, the car not only warps to one side, but there is also a knock in the rear wheel. The spring does not fit as intended. The solution to the problem is to replace it with a new one.
It is also worth inspecting the rubber spring gasket on the top and bottom side. Over the years of operation, rubber is destroyed. As a result, the gasket does not fulfill its function and the coils of the spring rub directly against the metal.
We continue to study why the rear right wheel knocks when driving. It doesn’t matter if it’s the 9th Lancer or the VAZ - the bearings hum the same when worn. But the sound is very insidious. At first, it will be barely noticeable. If you do not find it in time, a broken clip can simply jam the wheel at speed. Also, knocking occurs if the bearing is poorly tightened. To diagnose this, it is enough to jack up the rear wheel and shake it from side to side.
Pay attention! Do not over tighten the bearing. You need to leave a small gap in case of thermal expansion. A slight play is allowed. But if the wheel is wobbly, this already speaks ofproblem.
Be it a beam or an independent suspension, in any case, there are silent blocks in the rear suspension. They are designed to reduce vibrations and shocks that are transmitted to the body during the operation of the chassis. The resource of silent blocks is different and ranges from 100 to 200 (and higher for a semi-dependent beam) thousand kilometers. If these elements are worn out, play occurs. But even a slight backlash can provoke a knock, which will be clearly heard in the car. As with shock absorbers, this sound will increase on rough roads. How to solve a problem? There is only one way out. This is the replacement of silent blocks with new ones. On some cars, they change separately, on others - together with the suspension arm. After replacement, the sound disappears completely.
She can also provoke sounds in the rear wheel area. With what it can be connected? The reason will depend on whether the brake mechanism is installed - disc or drum.
In the first case, we can state the beating of the pads on the disk. Very often this happens on budget foreign cars. To solve this problem, it is necessary to revise the caliper. As a rule, bushings are worn out in it, along which it moves. Today, there are special repair kits that include rubber bands of increased diameter. They are installed instead of the old ones on the bushings. After that, the knock disappears.
In the case of reels, the situation is different. The sound may come frombehind a deformed drum cover. If it has an oval shape, during rotation, the element hits the pads. The result is a strange noise. In this case, the pads will have uneven wear when the cover is removed. In this case, the drum must be replaced with a new one.
So, we have considered why there is a knock in the rear wheel. As you can see, there are quite a few reasons. There are both banal and serious ones. But in any case, it is impossible to operate a car with such a knock. It is necessary not to delay the repair and fix the problem as soon as possible.