M3 rear subframe bushings increased height/wheel gap?

[pablom2c]

Hi,

I just installed VRSF intercooler, DINAN fixed front camber plates, and the four M3 rear subframe bushings.

When I picked up my car from the shop I noticed the front was raised a little bit which I expected from the fixed camber plates, but I also noticed the rear was significantly higher than before. The wheel gap is very noticeable. Is this normal? Even if the OEM bushings were in bad shape, can the new bushings raise the rear height that much? Or is there something wrong?

The shop told me it might take a few days for everything settle down since they had to take apart half the car to install the bushings, I drove the car a bit and everything seems very tight, there is no knocking or weird noises. I also have the front M3 control arms and B8 Bilstein dampers with the stock springs, I might go for the Eibach springs now that the car is raised all around to reduce the wheel gap and improve the handling further. I was worried the springs would cause rubbing because with my wide OZ wheels and offset (18x8 front et 34, rear 18x9 et 40) I had to roll the fenders before, but now it looks like the springs will fit without rubbing.

Let me know what you think?

...on to the next mods!

[ShocknAwe]

Make sure all the control arm bolts were torqued at ride height. If not the bushings will preload and the car will sit higher for a while. Downside to this is that the bushings will wear out much faster.

[Dackelone]

I second the idea a=of checking with the shop, that they torqued the suspension while it was on the ground. Otherwise the rubber bushings will be torn apart bc they are being twisted.

The way I did mine was to put the front(or rear depending on which axle you are working on...) up on jack stands Then loosen the bolt that holds that control arm... use a floorjack and a rubber or wooden block under that control arm... jack that suspension arm up - to simulate the suspensions ride height. Then torque that bolt - to specs.


The M3 rear subframe bushings are four units. Two for the front of the rear subframe and two for the rear part. See my DIY write up...

Dackel's replacement of rear suspension OE bushings with M3 ones…
https://www.1addicts.com/forums/showthread.php?t=638163

Maybe you can post some pics for us "experts" to analyze.

Dackel

[ShocknAwe]

Originally Posted by Dackelone

I second the idea a=of checking with the shop, that they torqued the suspension while it was on the ground. Otherwise the rubber bushings will be torn apart bc they are being twisted.

The way I did mine was to put the front(or rear depending on which axle you are working on...) up on jack stands Then loosen the bolt that holds that control arm... use a floorjack and a rubber or wooden block under that control arm... jack that suspension arm up - to simulate the suspensions ride height. Then torque that bolt - to specs.


The M3 rear subframe bushings are four units. Two for the front of the rear subframe and two for the rear part. See my DIY write up...

Dackel's replacement of rear suspension OE bushings with M3 ones…
https://www.1addicts.com/forums/showthread.php?t=638163

Maybe you can post some pics for us "experts" to analyze.

Dackel

This is accurate and how I did mine as well.

[tracer bullet]

I paid a shop (my kid was 2 at the time, that's my excuse), but I know they lifted the car by the wheels not the frame and had experience doing the job w/ other cars. I did nto notice any changes to the ride height at all.

[pablom2c]

Thanks a lot for your replies, I will check with the shop to see how they torqued the suspension.

[tracer bullet]

I'd consider asking them in a way that doesn't spill why you are asking. I.e. ask if it was lifted by the wheels or the frame. Maybe be ready with info documenting that it needs to be on the wheels, to present if needed. Don't try to trick them or anything, but also don't give them 100 ways out in case this is the issue and they did create it.

[iminhell1]

But it has to be aligned, or checked. So at some point it would have been lifted on the wheels.

[pablom2c]

Yes the car was aligned afterwards (-2.1 front camber!), and they have both type of elevators at the shop to raise from chassis or from wheels. But the one that raises from the wheels is for alignment, the other elevators that raise from the chassis is what they probably used to tighten everything... I'll see what they say.

To correct it they should raise it again by the wheels, loosen everything and retorque? They had told me to come back in around 500km to recheck everything is tight just in case.

[tracer bullet]

Originally Posted by dieguitov

To correct it they should raise it again by the wheels, loosen everything and retorque? They had told me to come back in around 500km to recheck everything is tight just in case.

That is the gist, yes. Not everything has to be redone, only certain parts. I'll have to defer to others as to which parts exactly. Other cars I've done the work on didn't have this characteristic, and I haven't had to wrench much on my 1-er, so I'm unsure about ours.

[TboneS54]

What exactly needs to be preloaded and tightened after subframe bushing job?

I guess it depends if they simply lowered it or removed it, but as far as I can tell, you're disconnecting the rear brake lines and rear shocks, probably at the bottom mount, before lowering the subframe.

But what else? Wouldn't the hub and control arms just naturally lower as the subframe lowers? The driveshaft will go with the diff.

You only need to preload bushings in joints that articulate. Bearings don't need preload (they spin freely in their nylon home) and bushings that don't rotate (like subframe bushings) don't need preload.

[dtla1]

Originally Posted by TboneS54

What exactly needs to be preloaded and tightened after subframe bushing job?

I guess it depends if they simply lowered it or removed it, but as far as I can tell, you're disconnecting the rear brake lines and rear shocks, probably at the bottom mount, before lowering the subframe.

But what else? Wouldn't the hub and control arms just naturally lower as the subframe lowers? The driveshaft will go with the diff.

You only need to preload bushings in joints that articulate. Bearings don't need preload (they spin freely in their nylon home) and bushings that don't rotate (like subframe bushings) don't need preload.

The control arms in the rear use regular bushings, not bearings. You may have already seen it, but if not, check out this thread for pictures and some light reading: https://www.1addicts.com/forums/show....php?t=1079383

[TboneS54]

I haven't, thanks for that! So are you saying you have to undo the control arms to lower the subframe? Thanks

[dtla1]

Originally Posted by TboneS54

I haven't, thanks for that! So are you saying you have to undo the control arms to lower the subframe? Thanks

IIRC, to install the M3 subframe bushings, you need to install them from the top of the subframe, so complete removal of the subframe is usually the easiest way to go so you can press out the original ones too.

Personally, I installed the two piece Whiteline replacements and was able to just lower the subframe a bit, but not completely, in order to install. Removal of the old ones was achieved with a torch and "pressing" them out using the weight of the car itself and a big socket to press it out.

[TboneS54]

That's my plan. I have Whiteline kit so install will be easy, maybe put them in the freezer first. I was contemplating buying the proper tool, but since I'm only pressing OE bushings out and not in, I'll try the socket/weight + penetrant maybe heat method.

My only research left is to figure out what all needs to be disconnected or loosened, that's why I was wondering what suspension parts are being undone such that they'd need to be preloaded before tightening - I don't see any rubber bushings (besides the subfame's) needing to be undone right?

Maybe unclip some sensor wires back there, undo the brake lines, undo the rear shocks at the bottom, done?

I agree though, if the shop completely removed OP's subframe, then it does seem likely that they didn't preload the arms before tightening resulting in the higher ride out in the rear.

I'm also hoping only lowering the subframe several inches is enough to install a rear swaybar and brackets. Really trying to avoid full subf removal.

[dtla1]

Originally Posted by TboneS54

That's my plan. I have Whiteline kit so install will be easy, maybe put them in the freezer first. I was contemplating buying the proper tool, but since I'm only pressing OE bushings out and not in, I'll try the socket/weight + penetrant maybe heat method.

My only research left is to figure out what all needs to be disconnected or loosened, that's why I was wondering what suspension parts are being undone such that they'd need to be preloaded before tightening - I don't see any rubber bushings (besides the subfame's) needing to be undone right?

Maybe unclip some sensor wires back there, undo the brake lines, undo the rear shocks at the bottom, done?

I agree though, if the shop completely removed OP's subframe, then it does seem likely that they didn't preload the arms before tightening resulting in the higher ride out in the rear.

I'm also hoping only lowering the subframe several inches is enough to install a rear swaybar and brackets. Really trying to avoid full subf removal.

I didn't remove the brake lines and was able to install my 2 piece whitelines. If you're going for the rear sway bar as well, I think you'll need more space though, not sure haven't done that myself.

Heat is going to be your friend getting the stock bushings out though, I don't think just penetrant and weight are going to do it, you really gotta get that outside surface of the bushing to melt in order to slide out. Maybe with a press you'd be able to do it without a torch, but on the car, I wouldn't think so.

But anyways, hope OP was able to get this sorted out.

[TboneS54]

Thanks for the tip, I'll have the torch ready.