Design and operation of the steering rack “Volkswagen Polo” sedan, the main malfunctions and repair with their own hands
Serviceable steering is a guarantee of safe driving in any car, including Volkswagen Polo sedan. Malfunctioning steering rack is the cause of many traffic accidents (accidents), so the reliability of this node car manufacturers pay a lot of attention. Volkswagen Polo, developed in the German concern VAG, is produced in Russia, on the territory of the Kaluga Automobile Plant. The car is deservedly popular among Russian motorists.
How the steering system in the Volkswagen Polo sedan is designed and works
The main node of the system that controls the car is the rack, which regulates the rotation of the front wheels. It is located on the subframe, in the area of the front axle suspension. The end part of the steering shaft of the column, on which the steering wheel is mounted, exits into the passenger compartment. The steering column also includes the ignition switch and the lever handle, which adjusts its position relative to the driver. The column is enclosed by a casing below the instrument panel in the passenger compartment.
The assembly that controls the vehicle includes the following main components:
- The steering column together with the steering wheel;
- PTO shaft, through which the column is connected to the rack;
- the steering rack, which controls the rotation of the wheels;
- electric power unit with control unit.
The steering column transmits the rotational force from the driver’s steering wheel to the intermediate shaft, with gimbals at the ends. This part of the steering system consists of the following parts:
- Upper and lower intermediate shaft gimbals.
- Intermediate shaft.
- The bracket that attaches the steering column to the body.
- The handle of the lever which controls the position of the steering column.
- The ignition lock.
- The shaft to which the steering wheel is attached.
- Electric motor with gearbox.
- Electric power steering control unit (ECU).
The geared electric motor generates additional torque for the shaft to which the steering wheel is attached. The ECU analyzes the speed of the car, the angle of the steering wheel, and the information from the torque sensor on the steering wheel. Depending on these data, the ECU decides to turn on the electric motor, facilitating the work of the driver. The steering column includes energy-absorbing elements that enhance the driver’s passive safety. There is also an anti-theft device that locks the steering shaft.
The ECU plays a special role in the operation of the system. It not only determines the direction and amount of force to be added to the steering shaft torque, but also reports errors in the entire steering system. As soon as a fault is detected, the control unit remembers the fault code and disables the electric power steering. The fault message appears on the dashboard to inform the driver.
The choice of the classical steering rack is due to the fact that VAG uses the McPherson suspension for the front-wheel drive of the car. The mechanism is simple and has a minimum number of parts. This causes a relatively small weight of the steering rack. The steering mechanism consists of the following main components:
- The traction lug of the left wheel.
- The pull rod, which controls the left wheel.
- Dust covers to protect against dirt.
- Drive shaft with worm gear.
- Housing acting as a crankcase.
- The linkage which controls the right wheel.
- Right wheel traction lug.
The device works as follows: the rack and pinion, located inside the housing (5), has on the ends of the attached pull rods that control the wheels (2, 6). The rotation from the steering column is transmitted through the driving worm shaft (4). Performing translational motion from the worm gear rotation, the rack moves the rods along its axis – to the left or to the right. On the ends of rods there are tie rods (1, 7), which interact through ball joints with pivot cams of McPherson front suspension. To prevent dust and dirt from getting into the mechanism, the tie rods are covered with corrugated dust covers (3). The steering rack housing (5) is attached to the front suspension cross member.
The steering rack assembly is designed for the entire life of the Volkswagen Polo sedan. In case of malfunction or poor technical condition that does not meet safety requirements, its main components can be repaired or replaced.
Video: the structure and operation of the classic steering rack control
Major steering rack malfunctions and their symptoms
Over time, any mechanism wears out. The steering rack is no exception. The degree of wear is affected by the state of the road surface in the region where the car is operated. Some automobiles fail already after the first 10 thousand km of run. Others drive up to 100 thousand km without any problems. Below is a list of common malfunctions Volkswagen Polo sedan and their symptoms:
- Tight rotation of the steering wheel . Can be caused by uneven tire pressure in the front axle or malfunction of the electric power steering. Stuck joints on the traction lugs also make it difficult to turn the wheels. Front suspension ball joints can also become wedged. A common malfunction is jamming of the steering rack drive shaft bearing. If the steering linkage sleeves are damaged, moisture can cause metal corrosion, resulting in heavy steering rack movement and wear on the locking sleeve.
- The steering wheel turns freely. If the wheels do not turn, the steering is defective. Worn rack gears and driveshaft worms require additional adjustment, using an adjustment bolt, or replacement of worn parts. Wear on the pivots on the traction lugs can also be a cause.
- Steering wheel play is greater than normal . This indicates wear on the steering parts. There may be play in the driveshaft joints of the intermediate shaft. You should also check the joints of the tie rods for wear. The nuts fixing the ball pins at the joints of the rack and steering rods may be loose. There is a possibility of wear on the rack drive shaft worm and toothed surface of the pinion shaft as a result of prolonged operation or lack of proper lubrication.
- Abnormal noises from the steering column while driving. Appears when turning the wheels or driving on a problematic road surface. The main cause is premature wear of the bushing that secures the pinion shaft in the housing on the right wheel side. There may be a large gap between the stop and the pinion shaft. The gap can be corrected with an adjustment bolt. If this does not help, the worn parts are replaced with new ones.
Video: diagnosis of steering malfunction
Can the steering rack be repaired
In most cases, replacing the steering rack is not necessary, as it is repairable. It should be noted that authorized dealers do not repair steering racks. Parts are not supplied to them separately, so dealers replace this unit completely. In practice, it turns out that the bearing included in the design of the drive shaft can be replaced. A bearing of similar size is purchased.
The sleeve that secures the pinion shaft can be ordered. It is made of fluoroplastic. If the pinion shaft is corroded, it can be ground with emery paper. Such an operation should be done, since a rusty shaft “eats up” the fixing bushing, made of a softer material.
Self-repair of the steering rack
If there is a garage with an inspection pit, an overpass or a hoist, you can repair the malfunction of the steering rack with your own hands. The knock and backlash of the pinion shaft can be eliminated by installing a new bushing, the sizes of which are presented above. This is one of the common malfunctions of the steering “Volkswagen Polo” sedan. To make this repair, it is necessary to grind the bushing and make incisions in it (see figure).
For disassembly and repair work you will need tools:
- Wrenches size 13, 16 and 18, with sockets of the same size;
- hexagon sockets of size 6 and M10;
- wrenches size 19 and 21 and sockets size 14 and 32;
- selfmade socket 36 (see illustration below);
- a removable pivot device;
- a grease for the rack – choose one that won’t degrade at high temperatures;
The work is performed in this sequence:
- The car is installed on the observation pit.
- The plastic casing of the steering column is removed and the carpet is unscrewed.
The car is suspended on both sides in order to remove the front wheels. For this purpose, supports are placed under the body.
If you do not remove the left tie rod, the position of the marks will be different, so the reassembly is also done with the left tie rod removed
The head for removing the shaft must be made by yourself or ordered by a master. In this case it should be remembered that the diameter of the drive shaft is 18 mm (the head should go through him), and the outer diameter of the head should not exceed 52 mm (it should freely pass into the hole housing). A notch must be made in the top of the head to use a gas wrench to unscrew it.
To remove the retaining ring, a rod is taken, bent and sharpened at one end. It is knocked out by tapping on the bar on the left side of the rod.
After everything is assembled, you need to check the steering wheel for ease of rotation and return to its original position. Then you need to go to a service station and make an adjustment of camber-convergence, so the car was not led aside on the road and the rubber on the wheels was not prematurely worn out.
Video: replacement of the bushing in the steering rack “Volkswagen Polo” sedan
Video: useful tips that will come in handy when replacing the bushing in the steering rack Volkswagen Polo sedan
As you can see, it is possible to repair the steering rack even in the garage. However, you need to have certain locksmith skills and appropriate tools. Practice shows that new bushings allow driving with serviceable steering control for another 60-70 thousand km. The knock on the rough road disappears and there is no backlash. Many motorists note that the car behaves on the road like a new one.
- Author: Igor Taranenko.
I am engaged in copywriting for 6 years, the last 4 years I chose this area of work as my major. Flawless in Russian, English I know on an average level. During this time I have written thousands of texts on a wide variety of topics.
Repair of the steering rack Polo sedan. Replacement of the bushing.
As you know, the rack on a polo sedan is one of the few sore spots. Since the design of thrust shaft bushing is weak – sooner or later the backlash starts, and then the knocking on the pits and bumps. Although the mileage of the original lattices is different, but in general many have already experienced the replacement of the bushing with fluoroplastic one, and the elimination of the nasty knock on the right side. The original rack lives for someone how, depends on the roads at the place of operation of the car, read who has already repaired – and the exact line here is not to fail. Someone “swim” with knocking begins in the first thousand warranty operation, someone at 50-60 thousand miles, someone even reaches 200 +. But as a whole all converge in one – sooner or later the bushing should be replaced. And the sooner you do it, the lower is the risk to kill the rack entirely due to continuous driving with broken thrust bushing. Well, our Polik had this problem at about 50-55 thousand. At first, hardly noticeable noise on the right side appeared only on hard bumps, ditches, and the hardest paving stones, which we have in the area as a fool to pickle. Replacement of the stabilizer rods and later bushings only reduced a little, but did not take away the noise, and then rushed into thoughts of problems in the rack. Finally dotted the “and” set the car service Monroe, where my father and I went to diagnose the suspension of a polo sedan about a month ago. The verdict was that the luggage rack was loose on the right side and the bushing was broken. Since it is a known sore, the masters check the rack on polo sedans in the first place if you have a knocking in the suspension. Mileage is 84,000 at the moment and the knocking is getting stronger, in ditches and on any paving stone it is noticeable now. Therefore we do not hesitate and order the bushing from Yaroslav Nasonov, in group VK “Autodetails”. The bushing comes ready to install, of the right size and with all the necessary cuts and notches. It is not necessary to rework anything, just take off one and put on another. First went around a few services in Kaliningrad to repair the steering rack, but the vague cost of repair, long deadlines, work only on weekdays, which is not suitable, as we live in the area and come to leave the car for a few days just can not. Everywhere else the need to grind the shaft, pull the sleeve strictly to the diameter of the shaft, the lack of a turner on weekends, the possible costs of complexity up to the unknown amount, as if diminished the desire to leave the car for repair. We did not see evident desire of the servicemen to earn money. It is clear that masters are reinsured for all occasions: for a rusty shaft and a rope, for broken teeth. Cars are different, they are operated in different ways, and therefore the condition of units can be cardinally different. Therefore it is possible to understand them. Well and final – in one of large services on repair of steering rack of passenger cars were sure that there is a rack with CPS in Polo Sedan, and it will be necessary to replace liquid and possibly seal hoses… it’s a fiasco… So following a rule “Do it yourself – do it well”, we collect everything that we will need for repair: bushing, greases, pullers, a head on “36”, move to Tohinator in Service Center ACP Kaliningrad for a weekend. On Saturday we planned to take the rack off and disassemble it, and on Sunday to replace the bushing, assemble and install, and to make a camber. So it turned out, except for a little bit of turmoil at the end of the day Sunday. But first things first.
In general, there are a lot of reports on repairing the rack on the Internet and on the drive, most of them differ from each other, we drew information from different ones, and already tried on the spot, the available tools. Therefore, in no way claim to F.A.Q. First of all we shall block a steering shaft in salon not to move a rudder extra time and not to tear off an airbag cable. Then in the passenger compartment unscrew bolt that fastens the cardan to the steering rack shaft – there is nothing difficult and we take out the cardan from the shaft. Further we elevator the car on an elevator and unscrew the steering cuffs from the knuckles. Here is the first problem – if nuts were unscrewed easily, then the pins were so rooted in cams that it was impossible to remove them with pullers. Since the tips hadn’t been changed yet, and in general they were in excellent condition. We had to knock them out – at the same time pouring and breaking the threads. Decided that the next day we would just run the threads and put them back on. That was the only mistake of the entire repair. By the way the left one came off easier, the right one got most of it…