Do-it-yourself Vito 638 steering rack repair

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

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

These are one 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 turning the steering wheel, you can hear an extraneous sound. It occurs when the rack breaks and malfunctions, 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: buzzing, creaking, etc.

• Noise when turning the steering wheel;
• Knocks when driving on bumps;
• Noise when steering in sub-zero temperatures.

There can be several reasons why you hear steering rack noise. The most common problems.

• Low power steering fluid;
• Power steering pump malfunction;
• Fluid leakage in the steering mechanism;
• Air entering the power steering system;
• PS bearing failure;
• Low fluid level in power steering.

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

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

Problem due to leakage. If cracks are present, 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, you need to 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're just trying to buy some time, you can leave the fix for later, but keep in mind that the car will not last long, and eventually it will be necessary 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 tank with 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 onto the tank;
6. We 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 to pour until it becomes clear that new liquid has flowed.

This procedure is performed by the master together, and very carefully.

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

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

According to their structure and principle of operation, the rails 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. They are equipped with most of the cars currently produced. 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 spool and a power hydraulic cylinder.
• Electrical. The amplifier is an electric motor controlled by an on-board computer. The electric motor can be built into the steering column, either placed on the steering shaft or integrated with the rack.

Unfortunately, during the operation of the vehicle, many car owners eventually begin to notice unpleasant phenomena, signaling that something is wrong with the vehicle's direction control system. Here are the most characteristic of them:

• Knocking when passing small bumps in the road surface, which becomes less intense when the steering wheel is turned to the extreme left or extreme right positions. It can also occur when the steering wheel is turned sharply to the sides with the engine turned off. Knocking is the most common symptom indicating a breakdown of this node.
• There is no noticeable effort on the steering wheel when rotating in both directions; force may weaken or disappear in the center position or when rotated to one side.
• Spontaneous rotation of the steering wheel.
• No return or very slow return of the steering wheel to its original position when making a turn.
• The car "throws" on the road when making a maneuver.
• 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 during operation) are most often:

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

Steering diagnostics is 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 a flyover or inspection hole. All the main components of the mechanism are studied, as well as the elements associated with it (in particular, the suspension).

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

The adjustment is made on a specially equipped stand. Adjust the backlash by tightening or loosening the adjusting screw located in the end cap. The screw is tightened slowly and carefully, while periodically checking for knocks, play and ease of rotation. With the help of a tightening, in some cases, the following problems can be eliminated:

• play;
• knock;
• lack of effort on the steering wheel;
• "heaviness" of the steering wheel;
• the 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.

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

Factory repair involves restoring the unit to its original condition. Repair begins with fault 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. During disassembly, hidden damage is revealed, then all components are washed again. After disassembly and washing, the components are checked for suitability for further use.

The geometry of the shaft 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 support bushings are changed.

Deformed and worn parts must be replaced. Elements that have undergone corrosion can in most cases be restored. Oil seals, Teflon rings, rubber bands are replaced with new ones.

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

After replacing all the rejected elements and restoring the repairable ones, the unit is assembled. 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 reinforced one, in order to check the reliability of the assembly and the quality of the oil seals and seals. After successful testing, the Mercedes Vito 638 steering rack remains filled with power steering fluid and is sent for reassembly, 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 fix the breakdown, but, if possible, contact trusted car services, with competent craftsmen and modern equipment.

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

• in the process of movement, carefully go around the pits;
• control the integrity of the anthers: even through a small hole, dust, dirt, sand will penetrate, which has a detrimental effect on 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 moving and actively 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 swivel wheels;
• try not to run into curbs and obstacles.

By following these simple rules, as well as passing 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 » Nov 10, 2011, 03:13

Message sib » Nov 10, 2011, 11:31 pm

Message StMoris » Nov 11, 2011, 02:49

Message djon1965 » Nov 11, 2011, 04:04 PM

Message Bronislavovich » Nov 11, 2011, 09:59 PM

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 a repair of Mercedes steering racks. Why is this happening?

Oddly enough, manufacturers have nothing to do with it: steering wheel bite, steering rack bending, gearbox noise are the reasons for the improper operation of a Mercedes, and indeed any other car with power steering. 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 begins to seize, that very characteristic knock appears due to the critical wear of parts. Check-in on the curb - 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: mercedes steering rack repair 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, colloquially - bushings.