I have an 05 MCS, and my alignment shop can't set up the right rear toe-in to any less than 6mm, but my left rear toe-in adjustment is perfectly fine.

Do I need new rear trailing arms?

Thanks
Elie

 

...dunno, how mant miles on your rig? I just ordered two new trail arm bushings...these may be worn on your car.

 

Less than 30,000 miles, meb. My suspension guy suggested new brackets. I thought bushes would be enough....

 

I'm kinda doubting you need new trailing arms. How good is this alignment shop? Even if your answer is, hey, they are a full race set up shop, that does not mean that the guy working on your car understands what's really going on.
The thinking that you may have a defective arm or bushing carrier is unlikely. It's more likely that this guy is missing something. Unless it's somehow broken, then you'd be better off thinking about new aftermarket control arms. Meb is right about making sure your bushing is OK.

 

This guy is voted the best in my state (i live in australia). However, his expertise is with *** race cars, and high end cars like porsche and ferrari (race and road). He's just never worked on a mini before, mine is his first.

He only had a glance at it, but if you guys seem to think it can only be a bushing, i'll tell him.

Firstly though, would a bushing deteriorate after 30k miles? Secondly, do you recommend that I go aftermarket?

I already have aftermarket rear control arms.

 

So is this "bad" control arms or trailing arms?

 

Confusing then. If you have aftermarket, "adjustable" control arms, then where lies this problem? There is no way he can say it's the trailing arm at this point. Who put in the control arms? The car would have been aligned at this point. If the control arms were not set to the exact same length as factory when installed then you may be all out'a whack.
Best way to do this is to start over and set your control arms to factory length. Then set you tow via trailing arms. OR, set both your trailing arms to center of their adjustment and lock'm down there. Then set up your alignment, camber and toe from the control arms only. This is what I do.

 

So, the R53 has another option other than the R56 arms for the trailing arm conversion??? I did not know they made after market trailing arms for our cars...

Can someone go more in depth?
Thanks

 

No, no aftermarket trailing arms that I know of, though anything can be made. The option that some use is the later factory aluminum arms.

 

Gotch ya...that is what I thought
Did not know if there were some racing ones made up or not...

 

I'm replacing the trailing arm bushings, not any of the 4 control arm bushings.

I have 121,000 miles on the car and I simply feel it's time.

...changing out all of the engine mounts as well - front end stuff was just done and JCW kit installed next Weekend.

 

Cool, i'll show him all of this when my car comes back from the repairer's. Thanks for the help guys, will update in a few weeks...

 

I am a Honda tech and do alignments on a daily basis. I would first loosen the bolts that mount the rear subframe to the body, allow the subframe to center itself (side to side) and tighten the bolts back up and try the alignment again.

The bolt holes in the subframe usually are a few mm larger than the bolts so there is room for the subframe to get pushed to one side a small amount (usually by hitting a curb I'd imagine) and when it does you'll get your symptoms.

 

True. This might help if he did not already have adjustable control arms. He does, so a subframe shift is not necessary.

 

this problem only showed up once i installed coilovers and dropped the rear 25mm....

But thanks for the tips, will show him all the above...

 

How hard is it to replace the rear trailing arm bushings? Is it costly? Should I go back to stock? I got about 122,000 on my 2003 Cooper with lots of hard driving, so it is probaly to to change them. How can you tell when they are totaly worn out?

 

Does he have adjustables for the upper arms as well? Or just the lowers?

 

Again, good point. I assumed it was all four, but if it's lowers only then your thought of shifting the frame is a good one.

 

This example doesn’t seem to apply here, since it only occurred after the coilover installation, but I know of an MCS that had a defective trailing arm, the distance between the hub spindle and pivot on the end was shorter on the bad arm than the good arm (read that as bent). It is possible damage could have occurred at some time before the owner took possession and repairs performed so it wasn’t noticeable, but just the same the disparity wasn’t discovered until it was put on an independent shop’s rack. So, measure the arms in case one may be bent.

If the subframe has shifted, there will be marks where the bolt heads located in the middle had been indexed previously, it is like that on mine but it hasn’t interfered with the adjustment range.

 

my adjustable arms have been fitted to replace the stock UPPER arms. My lower control arms are standard.

 

quick Q....he does know there are bolts up top on the trailing arm to the body for adjustment also, not just on the lower control arm?

 

not too sure. My car won't go in for another month, but I'll show him this thread when I go

 

Toe should only be adjusted at the trailing arm bushing - those 3 bolts. This is a big PITA adjustment as it takes a few hands to get it right. In several of my past alignment experiences, the techs used the adjustable control arms to adjust toe, and this is wrong. This method of adjusting toe will screw up a lot of things, but it appears easier at first...until the car is driven

Are all of the pieces attached? Are they installed in the propoer sequence? Is the ride height left to right identical - by measuring? Are all four lower links (two control arms, four links/bushings) in good working order - worm bushings? Add K-huevo's comments, and Onasled's thoughts and there are a few things to check. I offer these comments because on more than one occasion, I have made mistakes...very simple and stupid mistakes. Human we are.

 

This is new to me, will relay all the above, I'm betting that he used the arms to adjust toe, i never see more than one tech working on my rear alignment.

 

etalj,

Keep in mind, when a mini have only stock arms, toe can only be adjusted via the trailing arm.

Small changes to the stock geometry to correct for lowering camber won't hurt many things, but as soon as control arms are used to adjust toe, we get some very wierd camber and toe curves.

...set the car on jack stands on level ground, remove one rear tire, stand a small sheet of plywood up -vertical and perpendicular to the car's axis - in front of the rear axle. remove the spring. you can use any number of ways to plot a curve on the ply wood as the suspension is compressed...toe steer - toe out at full compression is bad!