Steering rack knocks: causes and their elimination. Steering rack repair

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

Not only the maneuverability of the car depends on the serviceability of the steering, but also your safety. In some situations, loss of control over a speeding machine can lead to irreparable consequences. Having found the slightest changes in the behavior of the car or extraneous sounds emanating from the elements of the control system, you should immediately stop driving and take measures to identify and eliminate malfunctions. In this article, we will talk about the reasons why there is a knock in the steering rack when the steering wheel is turned, and the possible consequences of this phenomenon using the example of a VAZ-2109 car. We will also try to figure out how to diagnose a rack and pinion malfunction and fix it ourselves.

Varieties of control systems

Steering design of modern cars can be of two types:

• worm;
• rack.

The first is equipped with almost all models of classic VAZs. It is called worm because the main element of the mechanism here is the so-called worm, which is a kind of continuation of the steering shaft. It is in constant engagement with the roller attached tothe bipod shaft, which, in fact, transmits the force to the tie rods. This design allows you to turn the wheels at a large angle and perfectly dampens the shock and vibration coming from the wheels.

Front-wheel drive VAZs of the Samara and Lada families are equipped with rack and pinion steering mechanisms. Their mechanism has a different design. Everything is a little easier here. The end of the steering shaft is equipped with a gear, which, pressing against a special rack with teeth on the upper side, makes it move in a horizontal direction. This design is simple, compact and highly reliable.

More about the rack and pinion mechanism

At first glance, the rack and pinion mechanism may seem quite complicated. If we take into account only its main parts, not counting the steering wheel and column, then there will be more than twenty of them. The rail itself looks like a shaft ground off to half.

On its upper part there are longitudinal teeth that engage with the drive gear. The rail is enclosed in an aluminum crankcase filled with a special lubricant. Its central part has holes for attaching internal tie rod ends. In this place, the crankcase has a cut closed with a rubber boot. Inside, the rail is held in a certain position thanks to a support sleeve, usually made of fluoroplastic. To adjust its mobility, a special stop is used.

As you can see, in fact, there is nothing complicated in the rack and pinion mechanism. If you understand what all the elements are for and how they work, you canmaintain and repair it yourself.

Rattle in the steering rack

The stock steering rack of VAZs, on average, "nourishes" up to 100 thousand kilometers. Naturally, in normal operation. In some cases, it can fail much earlier. The main symptom of a malfunctioning steering rack is knocking. It appears either when the steering wheel is turned sharply, or when it is turned out strongly, or when hitting bumps. Knocking in the rail may occur due to:

• loose thrust nut;
• loosening the tie rod bolts;
• natural wear of rack or drive gear;
• faulty bushing;
• wear of mechanism parts caused by dust boot rupture.

Next, we will consider each of the reasons in more detail, but first we will figure out how to correctly and accurately diagnose a breakdown.

Fault diagnosis

So, if you notice that the steering rack is knocking, you need to determine where exactly this knock comes from and discard the options for malfunctioning the elements of the chassis of the car. Let's start with the general points. Park the vehicle on a level surface. Get out of the cabin, open the hood. Start turning the steering wheel left and right, turning it all the way. If during this process the steering rack knocks, making a characteristic sound when the steering wheel is turned sharply, you can be sure that this is exactly it, and not shock absorbers or CV joints. For greater persuasiveness, ask the assistant to turn the control wheel, and put your palmon top of her crankcase. When the wheels turn out, you will definitely feel the vibration with your hand during this very knock. These signs are typical for the wear of the rack itself, the drive gear, or a malfunction of the support sleeve. Similar symptoms may occur when the stop nut is loose.

If there is no knocking when turning the wheels, pull the tie rods by holding them with your hands. If there is a problem, you will definitely find the corresponding backlash.

Thrust nut loosening

Often the steering rack knocks due to the loosening of the stop nut, which serves to adjust its movement inside the crankcase. The more it is tightened, the tighter the steering wheel will rotate, and vice versa. In other words, a nut loosened more than expected provokes a backlash between the rail and the stop. He is the reason for the knock.

Checking that the steering rack is knocking for this very reason is not difficult, but for this you need a special octagonal key for 17. You can buy it at any auto shop. Now you need to find the location of the nut. And it is located on the lower part of the rail crankcase in the area of the vacuum brake booster. It is usually protected by a plastic or rubber cap that will need to be removed. When this is done, try tightening the nut with a wrench by turning it counterclockwise. The tightening is considered normal when the nut is turned all the way, and then released by 24 degrees. This provides a gap between it and the stop equal to 12 mm.

Loose steering boltstraction

Each tie rod is attached to the rack with one bolt. They are located on the front of it, approximately in the center. To tighten these bolts, you will need a 22 wrench (head), as well as a large slotted screwdriver. With the help of the latter, you will need to bend the sides of the plate that lock the heads. Just tighten each of the bolts until it stops, checking with your hand for play between the rods and the rail.

Disassemble the rail

Now we move on to malfunctions that cannot be detected without dismantling the steering mechanism. If you have eliminated the play between the rods and the rail, as well as between it and the stop, and the knock has not disappeared, then you will have to dismantle the entire device.

Repair of VAZ steering racks is not a complicated process. Once you disassemble it yourself, and immediately understand the principle of its operation. First, remove the rubber support located on the right side of the crankcase and remove the rubber boot. On the left side, you must also remove the protective cap and support. Using an octagonal wrench, unscrew the stop nut and knock out the stop.

Pry off the drive gear rubber boot with a screwdriver and remove it. Unscrew the bearing fixing nut with a “24” wrench. Remove the gear from the crankcase. After that, you can pull out the rail itself.

Wear

Pay attention to the condition of the drive gear. Its teeth should not show signs of mechanical damage.

If they are present, it needs to be changed. The same applies to the rack teeth. Attach a gear to it andwatch them hook up. If there is wear, the mechanism should be replaced. Repair of steering racks, which implies their restoration, is possible, but hardly justified. Even if they manage to do something, it won't be for long. After a while, the malfunction will definitely manifest itself.

If the mechanism is worn out, there is only one way out - a new steering rack. The price of the spare part assembly is about 3500 rubles. Agree, it's not so expensive when it comes to security.

Support sleeve

Is the rack and pinion all right? Move on. We remove the fluoroplastic bushing from the crankcase. It is because of her that the VAZ-2109 steering rack most often knocks, or rather, because of its wear. If it is worn out or deformed, we immediately change it, since it costs mere pennies. But it is best to buy not just one, but a repair kit, which, in addition to it, includes an emphasis with a nut and a spring, as well as a set of seals and gaskets. Replacing the bushing and all these small elements, you will get a completely working steering rack.

Rupture of anther and wear of the mechanism

The rubber boot on the crankcase serves to protect the entire steering mechanism from dirt, dust and moisture. In addition, it prevents leakage of lubricant from the crankcase. You've probably heard the phrase "steering rack leaking". So, this grease flows through a torn anther. Its damage will inevitably lead to premature failure of the control mechanism. In addition to the fact that it will remain without lubrication, moisture and dust will also seriously accelerate the wear process. Discovering that inyour car is leaking steering rack, immediately go to the store for a new boot. And don't forget to buy some lube.