Since LEGO used their own interpretation of a servo i found it easier to build a new front part than to adopt their system.
Unfortunately I had only a rather big servo on hand so the whole part is a little long. I'm waiting for a smaller servo to add another (shorter) stl.
The front fender and all other parts of the LEGO axle can be reused.
I tried to integrade the parts of the servo, but the whole part is only slightly smaller and needs to be printed on point to work. So this way it seems easier.