so I came acrooss a similar issue with the idrive magnets where the idrive controller was sticking and not functioning properly after dismantling.
I have the solution to fix this and you need no washers / spacers to perform this.
follow these simple steps and you be done before you know it.
1- remove the back plate( it is held by 4 screws)
2- remove the magnets from the plate and keep the on the side, pay attention to the way they are sitting in the frame as they need to be re inserted in the same orientation.
3- (this is the most important part) grab the back plate and and tighten the screws while the plate is on a flat surface
tighten the 4 x screws untill 3mm of the screw end is visible from other side of the plate, make sure the screws ends are all equally tighten and you can see between 3 - 3.5mm of the screw ends.
Tip: place the plate on a flat surface and balance the screws, it is easier done than said.
4- place the plate on the idrive ( do not insert the magnets at this stage), make sure you do not apply pressure to the plate at this stage, you will notice the gap between the plate and screw is now increased, the gap should be no less than 1mm, tighten the screws. do not over tighten the screws to close the gap!
5- inser the magnets on the bottom plate, they should just pop into place.
thats all,
if the idrive still sticks repeat step 3 with increasing the screw ends over hang slightly.
I will try to post a video on how to do this. ps appologies for the miss spellign and grammer errors