DIY Vito 638 steering rack repair

One of the most favorite cars of all summer residents is the Mercedes-Benz Vito 638.

It is a convenient minibus for transporting passengers and cargo. Since summer residents often have to drive off-road and at extreme temperatures, alarming knocks and noise soon begin to appear.

These are some of the signs of a malfunction of the steering rack - the main part of the control mechanism. How to avoid a complete replacement, and what to do in such cases?

When you turn the steering wheel, an extraneous sound can be heard. It occurs in the event of a rail breakage and malfunction, and as a result, the Vito 638 steering rack may need to be repaired. The noise is very unique and no other component in your car will produce the same. Some describe it as: hum, squeak, etc.

• Noise when turning the steering wheel;
• Knocks when driving on irregularities;
• Steering noise in subzero temperatures.

There may be several reasons why you hear steering rack noise. Most common problems.

• Low power steering fluid;
• Defective power steering pump;
• Leakage of fluid in the steering gear;
• Air ingress into the power steering system;
• Defective PS bearings;
• Low power steering fluid level.

Repair of the Mercedes Vito 638 steering rack is quite difficult to perform, so you should contact qualified specialists. After completing the diagnostics and understanding the essence of the malfunction, you can make a decision - replace or repair. Let's consider various options.

The problem is a lack of fluid. If the noise occurs due to an insufficient amount of fluid in the power steering, then getting rid of the annoying loud noise will not be difficult. In less than 5 minutes, the problem will be fixed by refilling with a new one.

Problem due to leak. If there are cracks, due to which there is a rapid consumption of power steering fluid, a complete replacement of the steering rack is required. To add power steering fluid, remove the reservoir cap and drain it into a separate container. Be sure to use the recommended power steering fluid for the Mercedes-Benz Vito 638. If the repair is too expensive, or you are just trying to buy some time, you can leave the repair for later, but keep in mind that the car will not travel like this for a long time, and eventually you will need to do complete replacement of the entire steering mechanism, including the rack. Leakage is repaired by restoring dried, cracked and truncated rubber seals.

1. We pump out all the liquid from the reservoir using a syringe;
2. Disconnect all hoses from it;
3. We take it out and wash it from the inside with special equipment;
4. We muffle the "return" fitting on the barrel;
5. We pull the fluid supply hose to the tank;
6. Lower the "return" hose into an empty container;
7. We hang out the front wheels;
8. Pour new liquid into the tank;
9. The assistant turns the steering wheel from lock to lock;
10. We continue pouring until it becomes clear that new liquid has flowed.

The masters perform this procedure together, and very carefully.

The repair of the Mercedes-Benz W638 steering rack provided by our car service specialists can be considered in the following sequence:

The steering rack is one of the most important elements in the design of a vehicle, designed to transfer the force applied by the driver when maneuvering to the steering wheels. Its serviceability is a prerequisite for safe driving, therefore it is necessary to diagnose and repair the Vito 638 steering rack in time.

According to their structure and principle of operation, the slats are divided into:

• Mechanical.A protective corrugated cover is located inside the cylindrical crankcase, and a gear wheel is mounted on several bearings, driven by the steering wheel through the shaft. A toothed rack is pressed against this gear by means of a spring. Since there is no amplifier in this design, the steered wheels turn only due to the physical strength of the driver.
• Hydraulic. Most of the currently produced machines are equipped with them. Equipped with a hydraulic booster (GUR), designed to enhance the mechanical impact exerted by the driver to make a turn. The hydraulic booster consists of a pump, a pressure regulator, a reservoir with a supply of hydraulic oil, a control valve and a hydraulic power cylinder.
• Electrical. The amplifier is an electric motor controlled by an on-board computer. The electric motor can be integrated into the steering column, or placed on the steering shaft, or integrated with the rack.

Unfortunately, during the operation of the vehicle, many car owners begin to notice unpleasant phenomena over time, signaling that something is wrong with the direction control system of the vehicle. Here are the most typical ones:

• A knock when driving through small irregularities in the road surface, which becomes less intense when the steering wheel is turned to the extreme left or extreme right position. It can also occur when the steering wheel is violently rotated to the sides with the engine turned off. A knock is the most common symptom indicating a breakdown of this node.
• There is no perceptible effort on the steering wheel when turning in both directions; the force can weaken or disappear in the center position or when turning to one side.
• Spontaneous steering wheel rotation.
• Non-return or very slow return of the rudder to its original position when making a turn.
• The car is "thrown" on the road when making a maneuver.
• A constant drop in the oil level in the power steering reservoir.

The reasons for the failure of the elements of this mechanism (in addition to natural wear and tear during operation) are most often:

• Driving on dusty and uneven road surfaces.
• Frequent runs over curbs.
• Sharp acceleration of the car while holding the steering wheel in the extreme position.

The steering diagnostics are designed primarily to establish the size of the backlash (the gap between the parts). Diagnosis begins with an external visual examination. As a rule, for this purpose, the car is sent to an overpass or inspection pit. All the main components of the mechanism, as well as related elements (in particular, the suspension), are studied.

There are also special devices, the purpose of which is to more accurately determine the size of the backlash. One of them is a backlash dynamometer - an accurate device that allows you to determine the angular movement of the steering wheel of a vehicle. It is attached to the steering wheel rim. In vehicles equipped with power steering, the backlash is measured with the engine running.
Diagnostics allows you to determine whether it is necessary to sort out the rack and pinion mechanism, or the repair of the Mercedes Vito 638 steering rack may be limited to adjusting it.

The setting is carried out on a specially equipped stand. The backlash is adjusted by tightening or loosening the adjusting screw located in the end cap. The screw is tightened slowly and carefully, while the presence of knocks, backlash and ease of rotation is periodically checked. With the help of a brace, in some cases, you can eliminate the following problems:

• backlash;
• knock;
• lack of steering effort;
• "Heaviness" of the steering wheel;
• instability of the car when cornering.

After adjusting the screw, the vehicle is tested in motion, the force that must be applied during maneuvering is analyzed.

The diagnostics of the rail itself is carried out both at the stand and by an instrumental method. Its purpose is to identify the cause of breakdowns and defects in the assembly and to determine the repair scheme. Bench test allows not only to identify faults during the input diagnostics, but also to check the quality of the repair.

Factory repair involves restoring the assembly to its original condition. The repair begins with defect detection and visual inspection for mechanical damage.

The mechanism is thoroughly washed and cleaned, then disassembled in stages, with the utmost care to prevent damage to parts and working surfaces. A special tool is used to extract the internal structural elements. Disassembly reveals hidden damage, then all components are washed again. After disassembly and flushing, the components are checked for suitability for further operation.

The shaft geometry is checked on a special stand. If necessary, the shaft is replaced with a new one or it is ground and restored. In case of mechanical wear of the shaft, the bearing bushings are replaced.

Deformed and worn parts must be replaced. Corroded parts can in most cases be repaired. Oil seals, Teflon rings, rubber bands are replaced with new ones.

The body is checked for wear. Stubborn dirt and corrosion from the housing is removed by an automatic cleaning machine that can remove the outer layer several microns thick. Finishing of the body is carried out with the use of wear-resistant paints and varnishes, followed by regime drying in the infrared spectrum.

After replacing all rejected elements and restoring repairable ones, the assembly is performed. Then the rail must be adjusted and checked in the operating temperature conditions of the car - both in the standard load range and in the enhanced one, in order to check the reliability of the assembly and the quality of the oil seals and seals. After successful testing, the steering rack of the Mercedes Vito 638 remains filled with power steering fluid and is sent to the pre-assembly, where it is completed with steering rods and anthers.

Therefore, if you do not have the appropriate knowledge and skills, it is strongly recommended not to make independent attempts to eliminate the breakdown, but to contact, if possible, proven car services, with competent craftsmen and modern equipment.

Of course, prevention is always easier and cheaper, so here are some tips from experienced car enthusiasts on how to protect the steering mechanism from premature failure:

• while driving, carefully go around the pits;
• control the integrity of the anthers: even through a small-sized hole, dust, dirt, sand will penetrate, which has a detrimental effect on the working parts;
• do not fix the steering wheel in extreme positions for a long time - this creates a large load on the power steering pump and other elements;
• in the cold season, it is better not to start driving and active maneuvering immediately after the engine warms up; short and smooth turns will allow the power steering fluid to warm up;
• avoid turning the steering wheel when the car is stationary;
• do not allow sharp accelerations with the extreme left or extreme right position of the steering wheels;
• try not to run over curbs and obstacles.

Observing these simple rules, as well as passing technical inspections in a timely manner, you can significantly extend the life of the steering mechanism of your car.

Cars change, friends and the forum remain. [my.housecope.com/wp-content/uploads/ext/1209]

Message sib »09 Nov 2011, 22:49

Message StMoris »10 Nov 2011, 03:13

Message sib »10 Nov 2011, 23:31

Message StMoris »11 Nov 2011, 02:49

Message djon1965 »11 Nov 2011, 16:04

Message Bronislavovich »11 Nov 2011, 21:59

Message Shteek 12 Dec 2011, 00:22

The steering rack is the main part of the power steering. In fact, the most important part of it. Russian car owners often complain that they often have to repair steering racks, more often than their colleagues, even if This is the repair of Mercedes steering racks. Why is this happening?

Oddly enough, the manufacturers have nothing to do with it: biting the steering wheel, bent steering rack, gear noise - these are the reasons for the incorrect operation of a Mercedes, and any other car with a hydraulic booster. For example, in St. Petersburg, a typical problem is the loosening of the steering rack due to driving on tram tracks. A leak appears, the gearbox starts to jam, the same characteristic knock appears due to critical wear of the parts. Check-in on the curb is a bent rail, almost with a guarantee. If you like to hold the steering wheel in the extreme position for more than five seconds at full speed - wear will increase greatly, do not be surprised at a quick visit to a car service: repair of steering racks Mercedes only a lazy expert will not predict. By the way, such extreme behavior will also lead to wear of the power steering pump, contamination of the system, overheating of the oil and - the most unpleasant - breakdown of the steering rack seals and wear of the vertical rod bearing, in common parlance - bushings.