Did you find more or less by chance that your car seemed to lean slightly to one side? On closer inspection, it seems that the car’s attitude is not perfectly parallel to the ground (this can be seen more easily when the vehicle is lowered or lowered thanks to the mark of the wheel arches). The main causes of this phenomenon.
How to measure the difference?
First, we will have to try to be as precise as possible because it is necessary to quantify the offset between the two sides, but also to know if it is the front or rear gear that is concerned by the shift.
For that, we must take several measures to refine the results as much as possible. Also, the ground must be perfectly straight … If you have a doubt, park the car in both directions and take measurements to see if there is an impact on the positioning of the car. If the measurements are not the same on one side and the other, your floor is not perfectly horizontal. Also, remember to check the inflation of all tires.
Among the benchmarks that you can take about the ground are: the rocker panel, side turn signals located on the wings, door handles, wheel arches, etc. Attention, use mirrors may be misleading because they are usually not identical on one side or the other (same for settings).
You can also take measurements at the suspension system to see if everything is symmetrical on either side. In this case, it is essential to remove the wheels and thus to help a jack.
What are the possible causes?
Let’s look at the different possible causes of a difference in ride height between two sides of a car. However, you will need to clearly distinguish what type of train/axle is concerned. Indeed, if it is a rear torsion bar, the causes may not be the same as on a multi-link rear axle or McPherson front train or double-wishbone.
As you will explain this article, the shock absorberscannot be involved because they are not the ones who carry the car! So forget right away the shock absorbers to focus on the suspension.
Indeed, it is the spring that suspends (hence the name suspension) the car in the air, so it is she who assigns the height of the box.
So among the causes, it may be a tired spring that no longer has the same strength to “wear his side.” He crashes a little more on himself than his counterpart on the other side.
Some shock absorbers (as shown in the images below) can be modulated to adjust the ride height. I already see some who do not understand (because it is the spring that suspends) but you should know that the spring is supported on a damper element at the front, and this element is adjustable on the versions high-end (KW, Brillstein,etc.). So, it is enough that there is a shift between the adjustments of right and left so that the car is no longer right.
At the rear, the adjustment is not at the damper but at the location of the support that comes to accommodate the springs.
However, this scenario remains rather unlikely even if it is not totally impossible.
In the case where the rear axle makes its own, it will be necessary to check (in addition to possible springs, because there are not always in the case of a torsion axle) that the torsion bars are well positioned/set.
Of course, if a part of the bar is tired, then it will perhaps no longer suspend the car correctly (it is finally the same problem with a tired spring, except that here it is a question of other technique).
The pulled arm holding the wheel can also be touched and deformed.
Some silent blocs for undercarriages can have an influence. Indeed, by crashing/crashing, the car will lose a little height. Generally, this is accompanied by noises in the running gear because precisely the silent blocs do not do their job (it is then metal against metal) …Rubbers are allowing the setting of springs can also be involved.
Note also that the change of some silent blocsrequires to make a new geometry.