Question for those who have aligned their subframe
 

Can any of you who have performed this operation say with certainty that the subframe can be aligned?

The centers of the dampers up front vary by 3/4" when measured from the seam weld just to the outside of the strut tower. BMW says it's my Megans...I say it's the subframe.

Michael, you know my take on this, but I'll post it here anyway for argument sake.
The front subframe can not be moved. the two front mounting points are basically pinned in so they are going nowhere.
The rear is less precise in location and you might have about 3/32" movement in any direction.

Added this; What seam weld are you taking about? From where are you measuring?

Right the front Sub-Frame is pinned on both sides, so there is no way to get it wrong. do you have any photo's of the parts in question?

Hey Greg - I know your take, but I want to make sure and here's why; right after the Megans where installed, I asked the alignment tech for 2 degree negative camber. Now, assuming the Megan perch/camber plates are absolutely identical left to right, and, that the subframe cannot be adjusted, I assumed that the notches indicating the amount of camber left to right would be, in fact, should be identical or nearly so. (No corner balancing yet, so weight should not affect camber) I had the car aligned five times since the Megans where installed. The first four times, the passenger side indicated two notches less camber than the driver's side despite the camber being equal according to the techs. After the subframe was installed, the difference grew to four notches.

So, I played a little game at my expense; I made both sides equal and asked BMW mini to re-align the car. The tech said that somehow the driver's side was more positive than when he performed the work a week earlier - due to my purposely moving the damper. When the tech re-aligned the car for the fifth time, it was again four notches different. Each notch represents about 1/8".

Greg, while standing at the front of the car looking at the strut towers, there is a pinch weld - my words - to the outside of each openning in the strut tower. I wrote 3/4" difference, it is a half inch - still a lot. I mis-measured...I'm old:grin:

The Megan plates are symetrical, they are symetrically installed with respect to the uni-body. And, the tech I spoke with profoundly stated, "no way, it fits, or it doesn't." - about subframe adjustment.

So, something ain't correct...perhaps one bearing sticks out farther than the other in the knuckle...perhaps the engine mounts and therefore the axle locations are off...I don't know. But it bugs the hell out of me and I cannot in good conscience go any further with my setup until I find the problem...something just has never felt right and a 1/2" is a problem. I have the eyes and the know-how, just not the place or the tools.

...funny, the tech saif that the car's centerline and therefore tracks are within 0.01", basically perfect.


EDIT: - another observation and measurment; with the bonnet open, I used a level to determine the location of the top of the wheel rim with respect to the edge of the black plastic fender liner. The driver's side sits 1/4" under the liner and the passenger side is a hair more than 1/4" outside the liner. Clearly, this measurement supports the location of the dampers and points to a huge misalignment somewhere.

Any thoughts guys? Anything???

Michael

I'll check the Grassroots Motorsports article when I get home, but that's the source I know of for the idea that the front subframe and strut mounts can be "wiggled" to even things out.

Isn't one of the GRM staff a member here?

I gather you are sure that your wheels are exactly the same offset.

I do know that Mini coopers are NOT even from one side to the other. 1/2" out?... not sure that is more then the rest. There is no way you will get the sides even, and I think .5" is not that out of line in a Mini.

There is just nothing there that I can think of that could possibly have mis-aligned itself .
Loose bolts on the rear bushing?
Lower ball joint failure?
Front hub bearings OK?
Loose front hub?
Bent strut?

Just popped into my mind again about how these megans adjust, with that sleeve doohickey thing. I said from day one that I thought that it was going to be a problem, and I think between you and Sid that it just might be.

Keep us posted!
I'll keep thinking. My suspension and sub frame is complety disassembled on the shop floor so it makes it easier to think about all the parts involved.


Added this; I have to remember that my experience is limited here to an early '03 car. Things have changed but not sure the front sub frame and suspension has.

I missed your thoughts about the sleeve thing...would you please re-share?

Before these were installed, I adjusted the spring perches left to right using a digital micrometer. Left to right, front and rear is identical.

Ball joints are all new...in hindsight, an axle could not be the cause. Left to right caster is off a hair - basically within spec according to the tech...less than a 1/2 deg??? So this cannot account for the differences in camber.

Also, since the subframe was installed I get a severe pulling problem; if I make a 90 degree turn to the right, the car pulls to the right until I make a 90 degree turn to the left, Then it pulls to the left:sly: :eek: :eek2: . This car is really #$^#^&%^&%& up! Maybe time to sell it and buy an EVO...:impatient I was told by the tech that the stock springs are designed to wind-up as the car turns. Along with SAI, the steering returns to center as SAI lowers the front end, and, as the spring's energy is reversed...not too sure about that one...

Regarding aligning the subframe; if this were true, how would the steering rack re-align with the steering shaft? to my way of thinking, there cannot be any play in that area either. It fits or it doesn't...unless the rack moves on the subframe.

The rear bushing is perfect by the way. Hey...dunno, but are the stock dampers identical left to right. I just thought that maybe these are designed to gat around some hidden design...or flaw...I've got to go check these.

Here's the pertinent quote from Grassroots Motorsports, April 2006 issue:

"While front camber settings are technically nonadjustable on all stock MINIs, there is still something that can be done: Loosen the top strut mounts and wiggle these around to get the last little bit of possible negative camber. You can also loosen up the front subframe and shift the entire cradle to one side or the other to equalize the camber of the front wheels."

Of course, just because it is in print doesn't make it true.

snid,

I remember reading that article...April issue??? Well, I cannot get under the car for a few weeks - daughter's graduation, weddings, yadda, so on and so forth. But hopefully before my debut at the Glen on July 17th.