How to mount a banana-shaped coil spring correctly

We regularly hear about mechanics who have difficulties mounting banana springs (Side load springs / Lateral load springs).
 

In a MacPherson strut, a compressed coil spring will generate a force that constantly and with varying strength exerts a side load pressure on the shock absorber. This condition reduces the life of the shock absorber and its ability to ensure comfortable driving. 

 

 

A banana-shaped coil spring is designed in such a way that it, when fitted correctly, exerts an opposing force compensating for the aforementioned side load pressure. This creates a balance and leads to the best possible working conditions for the shock absorber, ensuring a longer lifetime.

Before disassembling the strut, it is important to notice the position of the spring with respect to which end of the spring that faces the strut bearing and which end faces the shock absorber's spring seat.  

 
 
It is only by turning the new coil spring correctly that it achieves its correct shape once the strut is assembled. Generally, it will be the "flatest" end of the spring that faces strut mount bearing and the most "open" end facing the shock absorber's spring seat. Furthermore, it is important to make sure that the ends of the coil spring are correctly positioned in the spring seats.
 
If the coil spring was turned upside down: 
 
The shock absorber will be exposed to sideways pressure that reduces the life of the shock absorber and its ability to ensure comfortable driving 
It can cause damage to strut bearing
The coil spring might scratch the inside surface of the vehicle’s fender, causing noise and possible deformation of the fender
 
Prospectively, the packaging of side load springs will be labeled with a QR codes leading to a fitting instruction.