So I've got sort of a strange issue (or, rather, set of issues) with my '13 Cooper S that I've not come across anywhere in my searches through the interwebs or forums.

The four symptoms are:
1) No matter what wheels/tires I have on the car, I hear road noise from the front end at low speeds (30-45mph).
2) At very precise spots in the travel of the steering, whether turning left or right, I feel a very slight vibration in the steering wheel.
3) When slowing down at very low speeds (10mph or so), the car seems to lurch to some extent.
4) When braking at high speeds (60+) I feel slight pulsation in the brake pedal.

I'll start with a bit of extra details on each point.

Point 1:
With the stock RE050a tires, the blizzak WS70s and alternate 16" bridgespokes I had on for the winter, and my current Continental ContiExtremeContact DW tires (on 17" infinite streams), I hear a "whirring" road noise constantly at low-medium speeds. All have been checked for balance a second time after their initial mounting (even the stockers). The sound is constant, and doesn't vary while turning but does vary by speed. I can't clearly determine the source. Whichever side I'm sitting on (driver or passenger) it seems to be coming from the opposite.

Point 2:
Generally when making a right turn at an intersection from a stop, there's a specific point of the turn (roughly where the hand bolster on the steering wheel is at the very top center as it turns) that I feel a vibration. It doesn't happen if I'm in a big empty space trying to reproduce the issue. I also feel a slight hint of this issue when the steering wheel is around the same position in the opposite direction while exiting roundabouts, but never while turning. If I'm on a long sweeping turn in a dipped section of road at higher speeds (50-55 or so), I also feel a slight hint of this same vibration. I also feel a similar, if not the same, sensation when at certain points when going around curved transitional areas between highways.

Point 3:
With the stock brakes, the centric rotors and EBC yellowstuff pads that were installed at ~900 miles, and with my current Wilwood brakes, I feel a lurching sensation at low speeds while braking very gradually. It isn't the brakes, since it has happened even from new on each of the other sets that I've had installed, so I can't imagine what it could be. I even went as far as to have the centric rotors that were on before the Wilwoods turned (with only 900 miles on them) to confirm that it wasn't a deposit issue, and the issue was still there.

Point 4:
This is pretty self explanatory. At moderate to high braking pressure at higher speeds (maybe 65+ or so) I feel a very slight pulsation...nay...not even pulsation, vibration when applying the brakes.

I've tried to have the dealership reproduce these issues a couple of times now, and they can't seem to understand what I'm explaining even if I have someone in the car with me when it happens. The car has only ~9k miles on it, but I've made mods so they may just be shrugging me off. Since I am my own warranty in the affected areas because I've changed the brakes a few times, I'm perfectly fine with correcting the issue myself. I'm really not sure what it could be. The vibrations seem likely to be a bad CV somewhere...but also seem like they could possibly be bearing or spindle related. I've done basic bad bearing testing (rocking the wheels from several angles on both sides), and didn't find any obvious sign of a failure there.

Can anyone make sense of this? I'm right on the verge of throwing on a pair of new driveshafts, pair of new bearing/spindle assemblies, and having my rotors turned. I'm confident that it would remove any of the possible culprits from the scenario, and would almost certainly resolve the issue, but it is (of course) a bit expensive at $1400 for new oem parts. I feel like pulling everything apart to replace only one (driveshaft assembly/spindle/bearing) would be half assed, so I don't think I'd bother with it. I also don't want to have newer of either on one side than the other, so if one side is getting replaced they both need to get replaced.

I haven't ever come across anything like this before. If I jack the car up and spin the wheels, they don't have any apparent wobble. If I watch the gap between the rotor and brake pad while turning, I don't see any evidence of sway there either. The alignment is correct as well. I've had enough bad luck with enough dealers over the years that I'm far past expecting that they'll fix it, especially considering the mods, but this is a real head scratcher. These issues are all extremely slight, and don't seem noticeable to anyone else that I've had drive my car. They don't seem like anything bad enough to make me think the car shouldn't be driven or that anything is seriously wrong. I'm super OCD about my vehicles though, so they bother me.

Short of the sledgehammer approach above that I'm considering, does anyone have any troubleshooting suggestions?

--Matt

 

Oh my, I hope I've not rambled on so long that no one will read this.

If there were any upgraded driveshafts available, they'd already be on the way to prep for swapping. The best I've found so far is a "not yet" from driveshaft shop. $550 apiece for replacement stockers is a tough pill to swallow though.

--Matt

 

Well, it looks like Driveshaft Shop will produce a set if I (or someone) sends them a set of sample Axles. It looks like used ones can be had pretty cheaply (<$200 for a set), but they recommend sending new ones for this process to avoid recreating some issue with the sample set.

--Matt

 

I ended up getting the dealer to look at this issue, but at fairly substantial cost (JCW BBK). Once they installed it they immediately noticed that points 1, 3, and 4 were still present. Replacing the wheel bearing on the front passenger side eliminated them. I've noticed, since I've had the car back, that 2 is still an issue. Now that my warranty is usable again, I'll give the dealership another try when I have some time.

--Matt

 

I am assuming the wheel bearing you speak of is the wheel hub?

http://www.outmotoring.com/mini-coop...b_bushing.html

If I understand you correctly, issues 1,3, and 4 are solved but not issues #2? Those assumptions made I would think the control arm bushings in the front may have uneven wear due to the wheel bearing being messed up in the first place. I'm assuming you've done an alignment but I would recommend getting these:
http://www.outmotoring.com/mini-coop...l_arm_kit.html

or

http://www.madnessmotorworks.com/mad...-bushings.aspx

I would hate for you to spend more money than you already have on this issue for me to be potentially wrong, but it may be worth a shot. After those are installed then get an alignment.

 

Yep, hub and bearing assembly. Just like that. Correct on #2 still remaining.

It has rumbled like that during turns since day one when I picked it up, so I don't think bushings are going to be the issue. Having spent all that scratch for the JCW brakes to get the warranty kicking again, I'm going to give them another chance to take care of it. The circumstances under which it happens (speed, steering angle, amount of throttle) are pretty precise though, so it'll take another day off work to get up there and drive it with someone. I've had them try to reproduce it 3 times now in a dropoff situation, and returned without anything having been repaired all but the last time when they replaced the bearing. I'm fairly convinced it's a CV, but I'm at their mercy unless I want to pay OOP for it (which would be kind of silly at this point).

I'm not sure how/why they were so certain that the Wilwood brakes had anything to do with the issue, but I can understand that they're not allowed to touch non-stock parts when working on warranty repairs. Oh well though, I like these JCW brakes just as well as those ones.

--Matt

 

Ah ok. For some reason I gave myself the impression that issue #2 was not a problem since you've had it (even though re-reading you clearly state it was). So that's my bad. In that case I would agree that you have a CV issue. That should be replaced under warranty by MINI/the dealership, but if this keeps giving you problems I would look at 'lemon law-ing' them. These are expenses you should not be paying especially since it's a '13 model year. What sounds does it make when it acts up? Usually CV's make a horrible noise if something is wrong.

 

Not really much of a sound. A slight rumble if anything. It's a mild vibration that can be felt throughout the car though, steering wheel and seats.

--Matt

 

Well, I think MINI finally fixed this. I kept going back persistently, and they finally escalated my issue to MINI Corporate. Someone came out to the dealership to look at the car and authorized a steering rack replacement. They completed the work and the car seems to be right now. I certainly have my doubts that the rack solved all 4 issues, and attribute it to being more likely related to the front end being thoroughly disassembled and reassembled, but all of the issues seem to be gone!

Who'da thunk?

--Matt