[squidlyboy]

Had some BC Racing BR-Type Coilovers installed recently on my 2014 328i M-Sport and after a few weeks of driving around, I want to adjust the rear ride height slightly and have some questions regarding the proper removal of the right bolts in order to do so. This is what BC Racing Technical Support told me at a very high-level:

1. Unbolt the Lower Shock Mounting Bolt and leave the shock dangling
2. Leave the spring attached and sitting in the spring cup/basket. It should be loosened
3. Unlock the Upper Spring Lock Ring, and turn Lower Adjustment Ring to turn the Threaded Perch - to adjust ride height
   • turn right-to-left (lengthen perch) to raise ride height
   • turn left-to-right (shorten perch) to lower ride height
4. Use a jack under the spring cup/basket to make sure spring is firmly in place - i.e. top/bottom has no movement sitting in the cup/basket (but zero pre-load - i.e. no spring compression)
5. Jack the cup/basket a little higher to compress the spring - 8mm-10mm to give it the proper pre-load - the extra compression/pre-load is to insure spring has no play and won't rattle or make noise
6. Unlock/loosen Strut/Shock Lock Ring and adjust shock height up or down by turning the threaded barrel until mounting hole lines up with mounting bolt hole in Control Arm
7. Attach mounting bolt through shock mounting hole to attach it to the control arm, then tighten
8. Tighten the strut lock ring against shock.
9. Tighten the Upper Spring Lock Ring against Lower Adjustment Ring to lock Ride Height Adjustment Perch.

This seems reasonable until i jacked up the car and took off the wheels. This is what i saw and now i have the following questions. I haven't called BC back as this now seems to be an F30-specific question, so i wanted to ask the F30 experts who have done the same for their BCs or other similar coilovers.

BTW, I hope this diagram is correct. Please correct if I've mislabeled/misidentified anything. I went by BC's description over the phone and tried my best to identify everything as accurately as possible.

• BC seemed to indicate that once the shock was loosened in step one, that the shock would just dangle and the spring would lower/uncompress. However given that there are two other bolts on both ends of the control arm that are attached, how would the spring uncompress/loosen? Am I thinking about this right? It seems that i would have to remove one of the mounting bolts on either end of the Control Arm to allow the spring to uncompress. Or does the whole control arm just lower (and separate from the spring) once the shock is detached? i.e. shock keeps control arm up and spring compressed?

• If the shock is what keeps the spring compressed, do I need to jack/support the control arm to even remove the shock mounting bolt in step 1? I assume the whole assembly is still under tension and that it would be hard to remove the bolt unless you relieve the tension by supporting the control arm prior to loosening the bolt. Is this correct?

[f30luxline]

Not same car but the principle is the same. This guy is a great source for reference.

I'll be installing my BC's this weekend and will take a couple brief videos.

[f30luxline]

I have installed my BC's. You shouldn't have any problems following what BC told you.

[squidlyboy]

Originally Posted by f30luxline

I have installed my BC's. You shouldn't have any problems following what BC told you.

Just saw someone finally responded to this. I had given up and decided not to mess with it This video is awesome. I think it answered most of my questions, so thank you for posting it up.

I get in jist what needs to be done, but i have some very specific questions.

1) Will removing just the one bolt attaching the shock allow me to just pull down the whole suspension by hand? The video seems to indicate so, but in the F30, there seems to be all these other bolts necessary to do so. I don't wanna do this work myself if its too complicated

2) Any idea what size that star bolt is that connects the strut to the suspension? Its a special item and i don't wanna have to buy a whole range of special sockets for this one bolt.

Thanks again for posting that vid - was super helpful!

[f30luxline]

1) Will removing just the one bolt attaching the shock allow me to just pull down the whole suspension by hand? The video seems to indicate so, but in the F30, there seems to be all these other bolts necessary to do so. I don't wanna do this work myself if its too complicated

Yes but.....It is best practice to loosen the inner control arm bolt. This would prevent the bushing from tearing/ripping and causing permanent damage. You will then need to replace the bushing and sometimes the whole arm. This is more prone on older cars where the bushing has already started to deteriorate. I took the chance and did not do this on my car and did not have any issues.

2)Any idea what size that star bolt is that connects the strut to the suspension? Its a special item and i don't wanna have to buy a whole range of special sockets for this one bolt.

All star bolts can be removed with a 12 point tool. I believe the size is 14mm