Every driver knows this unpleasant feeling: the car, recently pleased with the smoothness of the ride, suddenly begins to transmit to the cabin every irregularity of the asphalt. When car goes on the heelsThis is not just discomfort, it is a signal that the systems responsible for safety and controllability are not working properly. Ignoring such symptoms can lead to serious breakdowns and even emergency situations on the road.
Vibration, beating of the steering wheel or characteristic knock under the bottom are all symptoms that require immediate attention. In this article, we will analyze in detail the mechanics of the process, explain which nodes fail first, and help you understand when a visit to the service can no longer be postponed. Diagnosis of the suspension is a complex process, but the owner can recognize the basic signs of a malfunction.
Modern roads are far from ideal, and the load on the chassis is enormous. If your car shakes while driving, the reason can be in the banal imbalance of the wheels, and in the critical wear of shock absorbers or Silentblocks. Understanding the nature of these vibrations will help save your repair budget and keep your nerves on.
Diagnosis of shock absorbers and racks
The first thing that comes to mind when motor-car It starts jumping on irregularities, they're shock absorbers. Their task is to extinguish the vibrations of the springs, ensuring constant contact of the wheels with the road. If the racks "leaked" or lost their properties, the machine turns into an unguided projectile, especially at speeds above 60 km / h.
Check the condition of shock absorbers can be visually and by rocking. Check the rods for oily traces. If you notice the leakage, then the leakage is broken, and the oil came out. Such a shock absorber no longer works efficiently, and its replacement is necessary in pair with the other side of the axle.
- 🔍 Oil traces On the body of the rack - a sure sign of rupture of the osteoil.
- 🔍 Corrosion The rod can damage the cuff and lead to a gas leak.
- 🔍 Knock When passing by lying police officers often indicates wear of the bearing.
⚠️ Attention: Driving with faulty shock absorbers increases the braking distance on wet roads by up to 20% and can lead to aquaplaning even at low speed.
It is also worth paying attention to the nature of the movement after the pit. If the body continues to swing several times after the passage of irregularity, then the damping is broken. The correct suspension must return the wheel to its original position in one stroke. Prolonged pumping indicates that the internal throughput system of the valves is worn out.
Wheel and tire problems
Often the reason why shakingIt is not in the complex nodes of the suspension, but in the wheels themselves. Imbalance is the most common enemy of smooth running. Even a small weight that fell off the disk can cause a beat, which will be transmitted to the steering wheel and body.
Hernias on the sidewalls of tires or tread bloating are also sources of strong vibration. When moving on the bumps, the deformed part of the wheel creates a shock load, which is felt as a series of rapid shocks. This is especially noticeable at high speeds.
Disc geometry is another critical parameter. “Eight” on the cast disk or the deformation of stamping after falling into a deep hole disrupts the balancing. Visually, it is difficult to determine a small deformation, so with persistent (constant) vibrations, a check on a balancing machine is required.
When buying new tires, be sure to do a balancing exercise and check the geometry of the discs, even if they look whole. It'll prolong the life of the pendant.
Tire pressure also plays a role. The pumped wheels make the suspension "harder", transferring all the blows to the body. Unproven tires can cause a feeling of “wattiness” of the steering wheel and uneven wear of the tread, which eventually also leads to a beat.
Silentblocks and suspension levers
Silent blocks are rubber metal hinges that extinguish the oscillations between the suspension levers and the body. When the stains are broken or broken, they are stained. It is this backlash that often causes a thud when the car is driving over a gravel or minor irregularities.
Diagnose the wear of Silentblocks can be done by visual inspection. Cracks on the rubber part, bulging of the metal or a complete rupture of the inner sleeve indicate the need for replacement. Ignoring this leads to accelerated tire wear and violation of the wheel installation angles.
| Element | Symptom of wear and tear | Consequences of neglect |
|---|---|---|
| Silentblock lever | Knocking from the front, pulling away | Floating, tyre wear, tyre wear |
| Stabilizer sleeve | Screaming, knocking on small bumps | Body roll in corners |
| Ball-pillar | Deaf knock, backlash of the wheels | Wheel break, road accident |
Particular attention should be paid to the bushings of the stabilizer of transverse stability. They often fail first, making a nasty creak or knock. Although many consider them consumables, their condition directly affects the stability of the car in corners.
Resource of Silentblocks
The average service life of rubber silentblocks is 60-100 thousand km. Polyurethane analogues go longer, but transmit vibrations to the body more rigidly.
Steering and its influence on vibrations
If the driving bumps hits the steering wheel, the problem may be hidden in the steering tips or rods. The luft in these connections not only creates discomfort, but also makes driving dangerous. The car can scour the lane, requiring constant thrusters.
The steering rack is a complex and expensive knot. Wear of the gear pair or bearings of the shaft leads to knocking, which is often confused with suspension problems. If the knock gives to the steering wheel when passing pits, most likely, the rake requires repair or replacement.
- 🔧 Steering tips The primary element of diagnosis when beating the steering wheel.
- 🔧 The steering shaft cardinal - often rusts and wedges, causing jerks.
- 🔧 Hydropower Stifling the system can cause hums and vibrations.
⚠️ Attention: Luft in the steering is a direct threat to life. If a free steering wheel is found more than 10 degrees, the operation of the car is prohibited.
Checking of steering tractions is carried out by swaying the wheel in the horizontal plane with the car raised. The presence of free travel in the connection of thrust and rack or tip and rotary fist indicates a malfunction. Replacement is required in pairs to maintain the uniformity of the suspension.
driveshaft and drives (for rear and all-wheel drive)
Owners of rear-wheel drive and all-wheel drive cars may encounter vibrations, the source of which is under the bottom. The driveshaft transmits torque from the gearbox to the rear axle. Cardan imbalance or wear of cruciforms cause a strong vibration, which increases with increasing speed.
The crosses of the driveshaft are experiencing tremendous loads. When developing needle bearings, a characteristic metal clang appears when moving from a place and vibration when moving. The lubricant is washed out, the metal rubs against the metal, and the knot quickly collapses.
☑️ Diagnostics of cardan
The sling bearing also plays an important role. If its rubber clip is destroyed, the shaft begins to beat, creating a hum and vibration. In all-wheel drive cars, similar problems can occur with front-wheel drives (SRUS). The gnawed SRUS will crunch in corners and vibrate when dispersed.
Engine and transmission as sources of vibration
Sometimes the problem is not in the chassis, but in the power unit. If machine shaking on idle or when unloading the engine, it is worth checking the supports (pillows) of the engine and gearbox. The rubber metal supports extinguish the vibrations of the working motor. When they break, the engine rests on the frame or bodywork, transmitting all its vibrations.
To determine the malfunction of the pillow can be by opening the hood and asking the assistant to briefly turn on the transmission (on automatic transmission) or sharply gas (on manual transmission) while you keep your hand on the support. Excessive amplitude of the engine indicates a rupture of the support.
Transmission vibrations can also be caused by problems with the hydraulic transformer in automatic transmissions. Wear of the locking clutch causes vibrations at certain speeds (usually 60-90 km / h), which disappear when the load on the gas pedal changes.
Vibration, depending on engine speed, often indicates problems with the internal combustion engine or transmission, rather than with the suspension.
Frequently Asked Questions (FAQ)
Why does the car only shake at a certain speed?
This is a classic sign of wheel imbalance or driveshaft. There is a so-called “resonance frequency” at which the beating of an unbalanced element coincides with the rotational frequency, increasing. This usually occurs in the range of 80-110 km/h.
Is it dangerous to drive if you hear a knock on the suspension?
Yeah, it's dangerous. Knocking means there's a backlash. In an emergency (sharp turn, braking), the worn element (for example, a ball support or a Silentblock) may not withstand the load, which will lead to loss of control.
Can the car shake on the bumps because of bad gasoline?
Gasoline does not have a direct effect on the suspension reaction. However, detonating the engine due to poor fuel can create vibrations that will be transmitted to the body. But the characteristic knocking is from the irregularities of the road - it is always a mechanical problem of the chassis.
How often do you have to do a descent?
It is recommended to check the angles of the wheel installation every 15-20 thousand km of run or after any serious intervention in the suspension (replacement of levers, hitting a high curb). This will ensure uniform tire wear and stability on the road.