So... I seem to have a new problem having just got my oil leaks sorted!

When applying brakes at over 60mph the steeriong wheel wobbles. Everything is smooth when not braking or at slower speeds.

I have not taken my wheels off or done anything to the suspension nor brakes. The only thing I can think that I have done is jack up quite strongly on one side to get under it for fixing the oil leaks.





I'd have thought any damage to the suspension would be clear at all times, not just when braking. Also general suspension parts really shouldn't mind a bit of lean. However I did read somebody suggest on another forum for a similar issue, the front end links (anti-roll bar to strut links I assume?). Apparently they can bend easily. I guess they would be stressed with weight on one side and not on the other.

What do you guys think? Can these links cause wobble only on braking? Could my jackign up have damaged something else? I have been considering maybe the ABS computer needs a reset?

 

Have you checked your lower control arm bushings to see if they are worn out?

 

Does the car vibrate when it happens too? I kinda think you have some slightly warped brake discs.

 

Warped rotors.

Just went through the same Q&A for my Subaru Tribeca this week.

 

My first thought was brake discs but I really haven't done anything that could warp them. I also checked them and turning by hand the friction through the brake pads was constant.

The car doesn't seem to wobble, only the steering.

I'll have tocheck the suspension carfully when I have a bit of time. I hope it's not the wishbone bushing, that sounds a pain to change! Apparently the subframe needs to be lowered?

 

Could you detect any warp on inspection or was it undetectable?

 

I think it's possible bad LCA bushings could make the car vibrate when braking at high speed, and they're known to go bad. There are a couple of ways to change them without dropping the subframe. One is using a special bushing tool, and the other is with a saw, but you have to be careful not to damage the bracket with this method. There are videos on Youtube for both methods. Most people replace the bushings with Powerflex street/performance (purple) bushings.

 

Rotors get thin, and rotors warp. It happens under normal driving g conditions as well as hard drive g conditions. If you have the knowledge and a micrometer measure the rotor thickness. If thickness is good measure the lateral run-out of your discs. If lateral run-out is within acceptable limits and thickness is OK on all 4 corners than you can suspect a worn suspension item. As others have stated, possible control arm bushings.

Take a pry bar and pry on the arm near the bushing. It shouldn't move much if you have stock bushings. If you have poly bushings you can just assume they're not gonna move but do a visual inspection to make sure the polyurethane hasn't suffered damage and gotten smashed, ripped, etc.

I'm leaning towards rotors though. Could be an extremely loose wheel bearing as well--but you'd hear that before it got so bad it warped your rotors.

 

I don't feel any pulsing though the brake pedal, only the steering. So I think that, and no tight spots when turning by hand, rules out disc problems.

It's starting to look like a slightly worn wishbone bush on the passenger side. I can make the wishbone move back and forward a tiny amount by pulling and pushing on it. On the drivers side it basically seems to have zero movement in that direction. Slightly tricky to tell though becasue the car wobbles on the jack at the same time.

I'm going to take it to my friendly mechanic next week and perhaps he can test better than I.

So, if I do need new bushes, which do you think are better: Lemforder, Febi or Meyle? Anybody know who makes the genuine ones for Mini?

I don't want Powerflex, the ride is stiff enough already!!

 

You want power flex unless you want to replace those bushings over and over.

Also, just because your pedal isn't pulsating doesn't mean the rotors are not warped. Warped rotors often cause the steering wheel to vibrate.

Good rule of thumb, if the steering wheel pulsates when braking front rotors are warped.
If the brake pedal pulsates the rear rotors are warped.
That's almost always the case.

 

We'll see what the mechanic thinks, hopefully he has a dial indicator to properly test the disk for variation and a decent pry bar to test the bushes.

Why does the brake pedal pulsate with warped rear disks but not for the front ones?

 

Because there is no steering linkage in the rear. Think of it almost like a solid axle. In the front the steering rack and bushings absorb the vibrations. In the rear the caliper absorbs the vibrations whoch transfer to the brake fluid which then makes you feel it in the pedal.