Shock absorber front: 1 - telescopic stand; 2 - spring; 3 - compression stroke buffer with a protective cover; 4 - nut for attaching the rack to the body; 5 - support washer; 6 - nut for fastening the upper support; 7 - top support of the rack; 8 - bearing of the upper support; 9 - upper spring cup
Removing
We derive the steering knuckle from the eye of the rack bracket.
Holding the rack from falling, finally unscrew the nut of its upper fastening.
Remove shock absorber.
We remove the rubber-metal support washer of the upper mounting of the shock absorber strut.
To disassemble the rack, we install two spring ties diametrically opposite to each other, so that they engage four turns of the spring.
Evenly rotating the screws of the couplers, we compress the spring.
Care must be taken when working with a compressed spring.
After the spring stops pressing on the support cups...
...with a spanner «at 27» unscrew the nut securing the upper support, holding the stem from turning with a hexagon «for 6».
Removing the stand...
...upper support bearing...
...and the top spring cup.
We remove the spring with couplers.
...compression stroke buffer with protective cover.
We assemble and install the rack in reverse order. Install the spring...
... so that its lower coil rests against the protrusion of the lower spring cup...
... and the upper coil rested against the stamping of the upper cup of the spring.
We tighten the nut for fastening the upper support of the strut and the nuts for the bolts of fastening the strut to the steering knuckle to the prescribed torques. Tighten the nut securing the strut to the body finally to the prescribed torque in the position «car on wheels»
Tightening torques (N·m)
Nut of the top fastening of a shock-absorber rack to a body - 44
Nut of fastening of the top support of a shock-absorber rack - 62
Nut of a bolt of fastening of a shock-absorber rack to a rotary fist - 105
About the repair of modern shock absorbers
The shock absorber, or shock absorber strut, was not a particularly complex product before, but now times have changed, and ubiquitous marketing is trying to limit the ability to repair any part of the car. However, against the background of a significantly increased cost of dampers, the relevance of their repair has again increased significantly.
The economic crisis in Russia has managed to be noted here too, but one should not think that only we are engaged in the restoration of components and assemblies, this practice is widespread throughout the world. Okay, high-pressure fuel pump or generator, but do they really restore shock absorbers? Perhaps this will seem surprising to someone, but this is true, moreover, for example, in the original VAG program, restored components and parts are indicated by a letter «X» at the end, a well-known fact, i.e. a customer who wants to save money can order remanufactured dampers directly through official channels. This, of course, is not our way, but there is such a possibility.
However, it is worth starting from the very beginning, namely with the problem that has arisen, and only then outline the possibilities for solving it. Automakers often say one thing, suppliers to the conveyor another, but everyone agrees on one thing - a shock absorber, like any mechanical device, has its own service life. If we talk about classic circuits without newfangled electronic bells and whistles, the damper lives no more than 80,000-100,000 km, this is the limit. It is quite possible that even after this run the shock absorber will remain operational, but only partially. In that «partially» and the main trouble lies - for such racks, the damping level can decrease by 50% or more, and this is the safety of control in border modes - do you need it? The above should also be taken as a guide to action: «Yeah, my shock absorbers have passed only 40 thousand, which means that everything is fine with them». Not at all a fact - it all depends on where, how, at what pace and with what load to ride. It is completely possible to finish off the suspension of a modern car even for a thousand kilometers, especially in the corresponding directions - a stupid thing is simple, so the performance of the damping elements must be clarified in other ways.
The funny thing is that there are not so many of them. The best diagnostic tool is a master diagnostician with 10 years or more of work experience who is not involved in branded marketing programs. The fact that the shock absorbers are out of order or will soon completely fail can be determined by yourself - by the behavior of the car, and, of course, by the only method generally accepted by the masses: first swing the front, then the rear of the car. If the car swung more than once - the replacement is unambiguous. This is understandable, but even here lies a lot of nuances, so you need sufficient experience or a diagnostic stand. Of course, experience is better, since the universal stand will diagnose not the dampers separately, but the suspension as a whole, so this is not an option either. Naturally, there are specialized stands with strain gauges designed specifically to test the effectiveness of damping, but the trouble is that in order to test the shock absorbers, they will have to be removed from the car. Okay, the rear ones, although this has recently become difficult due to the widespread use of multi-links, things are even worse with the front ones, especially in the case of the McPherson type, and after installing them in place, you will also have to do wheel alignment, so the cost of disassembly is assembly-installation with related work may well be compared with the cost of new conventional shock absorbers.
But this is in the case of the old-school classics - gas or gas-oil dampers without electronic control. When an electronically controlled structure is installed on a car, the situation changes, since one shock absorber, depending on the brand, can cost a thousand euros or two, so here the question of a different order arises in full growth - how to repair a car without resetting the family budget? It is not customary to drive premium vehicles for a long time - usually this continues until a new generation of this model appears in the price lists of dealers. After that, as a rule, the car goes to the secondary market with its sores starting to crawl out, and their owners are by no means shareholders «Gazprom» or people's deputies. Therefore, the repair of shock absorbers has recently reached a new level - well-known companies in their field even declare that the service life of remanufactured dampers is comparable to the service life of new ones. Is it so? Another question immediately arises: maybe it is worth buying a repaired spare part from Europe? The roads are good, and the workers are conscientious. The statistics accumulated in recent years answers, in general, all questions. Remanufactured shock absorbers from Europe have their own characteristics, it should be noted that they are not the most attractive, and besides, one should not think that «there» they do well, but ours is bad, it all depends on the particular employee or the policy of the company. It was possible to meet the original restored dampers, ordered through the officials, of the best quality, and this was determined even by eye. The scourge of shock absorbers, which were like on good roads, is a very long service life and insignificant rod strokes. As a result, the chrome rod rubs against the stuffing box and guide bushings in the same place all the time, and the abrasive is everywhere. During repair, the stock does not change - it makes no sense, the maximum that they can do with it is to slightly polish it, so that when you see a restored shock absorber with a worn belt, you can most likely assume that it is from Europe. And a damper with a worn rod will not walk for a long time - microroughnesses will quickly disable the stuffing box and further with all the consequences.
Once, in the good old days, the designer-developer of any node in the process of work also thought about how, in which case, to repair a failed mechanism with minimal effort and money. Remember penny bushings, jets, oil seals, bearings, etc., sold both separately and as repair kits. Today, the design engineer has the opposite task - to make repairs impossible or as difficult and extremely expensive as possible. If earlier, when, for example, the McPherson front shock absorber strut failed, it could be done quite simply - remove the strut, unscrew the top nut, remove all the insides, pour out the oil, insert a new cartridge into the released cylinder and tighten the nut back, now everything has changed. From the point of view of logic, the old approach is clearer - well, really, why change a hefty rack entirely when you can limit yourself to a cartridge - cheaper and easier.
However, cheaper, simpler and more logical does not mean more profitable, so now all shock absorbers are non-separable - welded or rolled, and this is a general trend. Cartridges are still being produced by some people, but for classic racks it’s cheaper to buy a whole new part than to cut an old one, weld a spacer and cut a thread. But in the case of complex structures with electronic control, repairs are still cheaper, and several times cheaper, so there are still a number of companies involved in the restoration of shock absorbers.
Shock absorbers that have been on Russian roads usually fail due to broken guides, torn anthers and worn oil seals. Often, dirt gets into electronically controlled valves and solenoids, causing them to wedge and stop working properly. Due to shock loads, the seals of the working piston suffer, respectively, in most cases, the repair may well give the desired result. The main thing is that there should be no damage to the chrome-plated rod, otherwise this whole undertaking will become economically impractical. What about dirt? Like dirt, any damper components are easy to remove, rinse and clean. Repairmen always have repair kits and the necessary equipment for disassembly and assembly of an initially non-repairable design. First, the upper part of the shock absorber with the gland is cut off, then the rod with the piston is removed. With any result of troubleshooting, all sealing elements of the structure are replaced with new ones, and then the master checks the control devices for operability, and the cylinder and rod for scoring and wear. And the valves themselves are the most reliable part of a controlled shock absorber, so the matter is usually limited to flushing.
The assembly process, in principle, is simple, but it is necessary to apply welding work - welding a thick-walled sleeve in place of the cut off upper part and cutting an internal thread to install a screw plug with an oil seal. Depending on the gas pressure, either adapters or mortise fittings are used to create the necessary pressure in the system. After filling with oil and gas, the restored shock absorber is checked on the stand in all respects, now it is not difficult to do this, since it has already been removed. Usually, after repair, self-respecting companies give a one-year warranty on the restored product. On the one hand, this is not much, but on the other hand, it is the suspension that primarily suffers from inadequate users - I had to deal with customers who could kill even premium segment dampers in a month, consumer extremism is already a fully formed concept. So from this side, the warranty period is quite acceptable. In addition, the repair is also supported by the fact that it will be much easier and, importantly, cheaper to restore the rack a second time.
When buying advanced modern technology, it is worth remembering one significant moment. It will be expensive not only at the time of purchase, but also during operation, this is how modern marketing works, and the suspension of a modern car on our roads is in the main risk zone.