What is steering backlash, its causes and elimination


Backlash is a free play at the connection of two or more car parts. The allowable backlash is the maximum amount of displacement that is not critical for the controlled element.

This phenomenon can occur in:

  • steering control;
  • transmission driveshafts;
  • elements of the running gear;
  • suspension nodes.

Let's figure out the causes of free wheeling in the steering column. Then - how to fix it.

What is steering play

What is steering backlash, its causes and elimination

The steering column is the first node in which increased free play can appear. Its main part is a stem, which is fixed on the shaft with hinges.

The connection of these elements is provided by a gear train. Even from the factory, there is a slight gap in it. It is necessary so that the edges of the teeth do not wear out prematurely due to frictional forces.

What is steering backlash, its causes and elimination

The driver can notice this phenomenon by turning the steering wheel left and right so that the direction of the wheels does not change. During machine operation, the free play on the joints increases. This is most often due to the natural wear and tear of parts.

How car steering works - see the video review:

Lesson 37 General structure and principle of operation of the steering system

Breakage signs

Natural wear and tear of gear joints and hinge transmissions is slow, so it is difficult for the driver to notice from what moment the play began to increase. To control this process, the motorist must periodically check this parameter. So, for passenger cars, it is considered the norm when the free wheeling of the steering wheel does not exceed 10 degrees.

What is steering backlash, its causes and elimination

When, while driving, the car slows down the response to a turn of the steering wheel, the driver needs to stop and check what the reason is. This is a clear sign of a breakdown.

Any squeaks, knocks, vibrations, arbitrary deviation of the machine from a given trajectory - all these are signs of a malfunction of the steering. Because of this, in an emergency, the driver may not be able to control the vehicle and create an accident.

Steering wheel play

Fearing this, some motorists generally try to eliminate the free play of the steering wheel. However, this will accelerate the wear of the parts and they will need to be replaced with new ones more often than usual.

What is steering backlash, its causes and elimination

In the vehicle operation and repair manual, the manufacturer indicates the permitted steering play. If these data are not available, you should start from the basic requirements prescribed in the traffic rules.

The machine must meet the following requirements:

Vehicle type:Maximum allowable backlash (in degrees)

As you can see, the larger the vehicle dimensions, the higher the amount of steering free travel.

How to check the steering wheel play

What is steering backlash, its causes and elimination

Check the steering wheel play as follows.

  • Park the car on a firm, level surface - concrete or asphalt. Car wheels are dry, clean and set in the direction of the longitudinal axis of the body.
  • Before measuring, the steering wheel is turned left and right in order to feel the moment when the wheels begin to change their direction.
  • A device is installed on the steering wheel, which shows the degree of deviation from the center point.
  • Free turn left and right indicators are added together.

What tool is checked

The easiest way to measure rudder backlash is with a regular ruler. A mark is made on the steering wheel. Then it is turned to the right, the ruler is placed with a scale to the mark, and with one edge it rests on the left rack. When turning freely to the left, the mark will pass several divisions on the scale. It should be noted that this method is not accurate for passing a vehicle inspection.

Here's another way to determine the total backlash:

How to check the steering wheel play yourself

To accurately determine the amount of backlash, you need to purchase a backlash meter. There are two types of these devices: electronic and mechanical. The former are more accurate, can have multiple functions and are very easy to use. The second category does not need batteries, and they are highly reliable.

This is how the electronic model works:

How to check the steering play with the ISL-M device

Possible causes of backlash and their diagnostics

In addition to the natural wear of parts, the reason for the appearance of a free wheeling in the steering column is a consequence of the malfunction of the parts involved in driving the car. All breakdowns can be diagnosed in the following three ways.

What is steering backlash, its causes and elimination

With the engine off

If increased free play is felt with the engine off, the entire steering circuit must be checked. Here are the main problems that diagnostics can reveal:

  • steering tips worn out;
  • breakage of the steering rack shaft cross;
  • development of rack gear on the teeth;
  • if the car is equipped with a steering gear (old cars in which it acts as a power steering), then backlash may appear in its mechanism;
  • wear of the upper or lower ball joint.

When driving

What is steering backlash, its causes and elimination

If the steering wheel is loose while driving, you need to pay attention to the accompanying problems.

  • The car pulls aside. The reason is not adjusted wheel alignment.
  • When the steering wheel is turned, there is an abnormal noise. The reason is insufficient power steering fluid level.
  • Knock at the front when driving on rough roads. The reason is the failure of the steering rods and their ends. If this knock gives to the steering wheel, you need to check the steering rack.
  • Steering vibration. It occurs when the wheels are out of balance. In addition, the cause of the rudder runout may be a breakdown of the ball joints or steering tips.
  • Loss of ride. A jerky turn of the steering wheel indicates wear on the steering rack.

When braking

What is steering backlash, its causes and elimination

Free play of the steering wheel that occurs during braking may indicate problems such as:

  • failure of the hub bearing. You can identify this breakdown by lifting the car on a jack and shaking the wheel. If it is loose, then the problem is in the wheel bearing.
  • after a recent repair of the chassis mechanics, the hub fastening was poorly tightened;
  • the steering mounting bolts are loose;
  • wear of brake discs or pads.

Any changes in the behavior of the car on the road are worthy of close attention of the motorist. Ignoring alarms is fraught not only with the failure of parts, but also with the creation of an emergency.

How to eliminate backlash

In many cases, steering play can be eliminated by properly adjusting the vehicle controls. It is worth checking the tightness of all fastening bolts, and also pay attention to the adjusting screws. How to remove steering play in difficult situations?

In the steering column

What is steering backlash, its causes and elimination

Cardan joints are fixed on the steering shaft. There are two of them in standard columns. They are fixed with bolts. Another reason for free play in the steering column is the development in the nests where these elements are installed.

To carry out repairs, you will need to put the car on an overpass or drive it into a garage with a viewing hole. When replacing the crosspiece, the steering wheel must be fixed. If, after replacing the joint, the driver hears a rattling sound, the fastening bolts must be tightened.

Elimination of the backlash in the steering gear (if it is present in the car) is carried out by adjusting the gap between the bipod shaft and the worm shaft.

Steering wheel

What is steering backlash, its causes and elimination

It is rare, but it happens that a complete replacement of all worn parts does not eliminate the increased free play. In this case, check the installation of the steering wheel itself. In some cars, the gear fastening of this part fails due to the poor-quality material from which it is made.

So, eliminating play in a car's control system is not just a matter of comfort. The safety of everyone in the car depends on the health of its elements.

Here's another helpful tip for tuning your steering:

How to tighten the steering rack with power steering? Is it worth REPAIRING?


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