Steering and power steering – how does it work and what goes wrong?
A car's steering system determines whether the car goes where the driver wants it to, and whether it does so without vibration, nervousness, and noise. Power steering relieves muscle strain, but also stabilizes the driving line and enables precise steering in the city and on the highway. Four components most often determine the steering feel: the steering wheel and buttons, the steering column, the gearbox (with rods/ends), and the pump or EPS module itself. Replacing a used steering wheel with an original one from the same family can have a huge impact in maintenance and "rejuvenation" projects – it's a quick improvement in ergonomics and appearance. This article summarizes definitions, typical faults, "from the garage" diagnostics, and indicates sample models from the offer (BMW, Audi, VW, Mercedes), including steering wheels and columns. Global Parts helps assemble kits without improvising adapters and small parts, which shortens repair time.
Steering system – what it consists of and how it works with the power steering
A well-handling car is the sum of: the steering wheel, the steering column with its adjustment mechanism, the rack and pinion, and the rods and ends that transmit motion to the steering knuckles. Power steering is hydraulic (pump + fluid), electrohydraulic (electric pump + fluid), or fully electric (EPS in the steering column or at the steering rack). Leaks are most likely to occur in hydraulic systems, while EPS systems are more prone to warnings and "failures" of power steering due to torque sensor errors. A "stiff" steering wheel during maneuvers, knocking when turning, and "floating" on ruts are signs that the system is losing precision. In a well-maintained system, the response is linear, and the wheels return to a straight line without resistance or "searching for direction." Original, used components provide a natural support for the user. that maintain geometry and joints – replacement is quick and predictable.
Support – three solutions and their nature in practice
Classic hydraulics provide "oil" vibration filtering and easily handle intense turns when parking, but require tight lines and a healthy pump. Electrohydraulics allow for speed-dependent force control and do not burden the engine with a belt, but are sensitive to the tension and condition of the masses. EPS ensures the lowest power consumption and cooperation with assistants, but any play in the strut and bearings can be "heard in the hands" more quickly. In any variant, periodic inspections are worthwhile: fluid level (hydraulics), voltage and controller errors (EPS), end play, and the condition of the bellows/dustproof covers. 
Symptoms and Diagnostics – What Your Hands, Ears, and Meter Will Tell You
The most common symptom of a problem is a knocking sound when quickly turning the steering wheel on the spot or a "click" when starting after changing the direction of the turn. Vibrations on the steering wheel that increase with speed usually indicate problems with the ends/rods or hub bearings. or a joint in the steering column; vibrations that decrease after releasing the throttle are more often related to the linkage and geometry than to the wheels. Rough operation "when cold" often indicates too thick a fluid or air in the hydraulics, while random hardening in the EPS requires checking the faults and wiring. A simple "at a standstill" test: vigorous right-left turns with the audio turned off - repetitive "clicks" on the same side are almost always the joint/end piece. If play in the steering column is suspected, the mechanic will assess it by touch and observation of the shaft movement - steering wheel movement without wheel reaction confirms the problem.
Home tests and when to go to the service center immediately
It's worth checking the tire pressure and condition yourself, looking for leaks in the transmission, listening to the pump after starting, and driving in the E-class at 60-80 km/h. If the car "teeth up" when turning or the steering wheel sometimes "freezes," the workshop should check the voltages, grounds, and EPS error memory. Failure to return the steering wheel to straight after a curve often indicates a seized strut bearing and requires disassembly. After hitting a curb or pothole, it's essential to inspect the tie rods and ends, followed by an alignment to avoid tire damage.
Steering wheels and buttons – a quick refresh of the cabin and a real impact on driving
A new (for your car) used steering wheel can transform the look of your car in 15 minutes – a thicker rim, better stitching, and proper ergonomics mean everyday comfort and a more secure grip. The offer includes: BMW E46 steering wheel, BMW E90 and BMW E90 M Package steering wheel, BMW E60 M Package steering wheel, AMG/Mercedes AMG steering wheel, Audi S Line steering wheel (A3 8P, A4 B8), Golf 5 / Golf 5 GTI steering wheel, and Passat B6 steering wheel. . Replacement within a generational family is usually done "point by point", and it is worth including rims/ribbons and horn button modules compatible with the controller in the kit. For users who value "feel", a steering wheel with a larger circumference or with thicker "paddles" under the thumbs improves the feeling of the car and reduces wrist strain on the road. Used original rims fit better into the board and do not require modifying clips, brackets or pads.
Examples of models – what fits and what to pay attention to in practice
BMW: BMW E46 and E46 M package steering wheels usually work with the factory airbag, as long as the connectors match; in the E90/E90 M package, you need to choose the ribbon cable and button controller. Audi: Audi A3 8P steering wheel and A4 B8 (including S line) have different wiring harnesses for the airbag and buttons – a set from the same model year limits coding. VW: the Golf 5 / Golf 5 GTI steering wheel and the Passat B6 steering wheel differ in the button module and the shape of the wreath; it's best to use a set with tape. Mercedes: the AMG steering wheel often requires a compatible button module and airbag bezel – a "family" set shortens installation time. During each replacement, remember to disconnect the battery and check the module numbers to avoid the SRS warning light coming on.
Steering column and gearbox – where play and noises arise
The steering column transfers the movement of the ring gear to the transmission, and its bearings and universal joints suffer particularly in bumpy conditions and after years of storage. The offer includes: E36/E46 steering column, BMW E39 steering column /E90/E60, Audi A3 8L steering column, Audi A4 B8 steering column, and Mercedes steering column (including Sprinter). If steering wheel movement doesn't immediately translate into a change in trajectory, the first on the list are the universal joint and the bearing near the bulkhead – these are vulnerable to corrosion and contamination. A BMW F10 steering rack or Audi electric racks can come alive after a thorough wiring harness service and cleaning of the linkages, but mechanical play cannot be "coded." Every time the column is touched, the airbag mounting and its interaction with the belt are checked – safety comes first.
Rods and Ends – Small Parts, Big Impact
The BMW E46/E90 steering rack, Audi A3 8L /A4 B8 steering rack, and Mercedes W203 steering rack are responsible for the "final stretch" of motion transfer to the wheel. Worn-out steering rod ends cause delayed steering response and "floating" when braking, and replacing them without adjusting the geometry is half the battle. Boots protect the joints from sand and salt – cracked rubber boots accelerate wear and bring water into the rack. It's good practice to replace them in pairs (per axle), as asymmetric play disrupts steering feel. After installation, the car should "return" to driving straight at the same pace on left and right bends.
Power steering – fluid, pump and EPS in the "no surprises service" version
In hydraulics, the fluid level and color are measured (brown burning smell = needs replacing), leaks are checked, and the pump noise is checked at the steering limits – a prolonged whine is a classic symptom. In electrohydraulics, the wiring harnesses and voltage under load are monitored – voltage drops can "switch off" the steering assistance. In full EPS, the controller evaluates the torque on the column and supports only as much as necessary; torque sensor or power supply errors are visible as random hardening. In popular models (BMW E90 power steering, BMW E46 power steering, BMW E87 power steering ; Audi A3 8P power steering / electric Audi A3 8P) used OEM kits with a complete wiring harness can shorten diagnostics. In each of these systems, damaged clamps and hydraulic fluid are regularly replaced, and in the EPS system, clean grounds and stable power supply are ensured.
When to combine work with other systems
If you're planning to replace the steering wheel or column, it's a good idea to also schedule a linkage and geometry check – one visit, one measurement. When servicing the pump, it's a good idea to clean the fluid cooler (if applicable) to avoid heating the hydraulics in traffic. If the upgrade includes a steering wheel with buttons, it's wise to add the steering wheel tape/rings and the button module at the same time, in the same year group. In cars that have been in collisions, the straightness of the linkage and steering knuckle mounts should be checked – hidden distortion returns as pulling and uneven tire wear. 
Shopping and Assembly – How to Build a Basket Without Missing Pieces
Writing down the list of symptoms allows you to create a plan: "steering wheel + ribbon + buttons", "column + spider + bearing", "rods + ends + geometry", "pump/fluid or EPS harness" It's worth remembering that checking part numbers (e.g., by catalog number) protects against erroneous purchases. In the cabin, used (original) steering wheels provide the quickest results – they fit the dashboard and airbag without the need for additional clips; the "steering wheels and horn buttons" section makes selecting sets easier. In mechanics, it's best to "package" the work: tie rods in pairs, axle bushings, and afterward, geometry – once and for all. The final step: a short test drive on a flat road and in "E" mode to feel that the car handles naturally and evenly.
TABLE – Steering system: symptom → possible cause → what to do (abbreviation)
| Symptom | Possible cause | What to do |
|---|---|---|
| Knocking when turning in place | tip/rod/cross | element replacement, bellows inspection, geometry |
| Vibrations increasing with speed | tips/bearings/covers | even exchange + angle setting |
| Random support hardening | EPS/harness/voltage | error diagnosis, ground cleaning, harness repair |
| Howling at the ends of a turn | pump/fluid | fluid change, check of clamps and radiator |
| "Stagnation" after the arc, no return | column bearing | disassembly, lubrication/replacement of bearings |
TABLE – Steering Wheels and Columns: Model Examples and Tips
| Model / series | Steering wheel/column | What to watch out for |
|---|---|---|
| BMW E46 | BMW E46 steering wheel / E46 column | airbag and strap compatibility, crossmember and bearing |
| BMW E90 | BMW E90 / E90 M package steering wheel, E90 column | button module and wreaths, geometry on rods |
| Audi A3 8P | Audi A3 8P / S line steering wheel | various cushion bundles, button controller |
| Audi A4 B7/B8 | A4 B7 / A4 B8 / S line steering wheel, A4 B8 column | versions of the airbag cubes and frame |
| VW Golf 5 / Passat B6 | Golf 5 GTI / Passat B6 steering wheel | steering wheel tape and button module |
| Mercedes AMG | AMG steering wheel, Mercedes column | airbag frame and plugs – "family" set |
| BMW E39/E60/F10 | E39/E60 column, BMW F10 transmission | noise from the gearbox, regeneration or replacement |
FAQ – Steering and Power Steering \n\n| Question | Short answer | |---|---| | What is included in a car's steering system? | Steering wheel, column, gear (steering rack), rods/ends, steering knuckles and power steering (hydraulics/EPS). | | Is a used steering wheel a good idea? | Yes, the original steering wheel from the correct family will fit mechanically and retain the airbag/button functions. | | EPS or hydraulics – which is better? | EPS has lower power consumption and works with assistants; hydraulics filter vibrations better and are easy to service. | | Where does the clicking sound on the steering wheel come from when turning? | Most often, the ends/rods or the column cross; even replacement and geometry help. | | How do you know if there is a problem with the power steering pump? | Howling at the ends of a turn, heavy operation at low revs, fluid "boiling" - check level and clamps. | | What to order when replacing your steering wheel? | Wreath, appropriate tape/wreaths, button module and compatible airbag frame; preferably a set from the same year. | | When to choose a service instead of a "garage"? | When EPS reports errors, SRS/airbag is involved or angles need to be adjusted after replacing the rods. |