[harshm235I]

Hello,

New to the forum, so here goes.

Was driving in snow last night and hit a curb pretty hard, looks like a broken lower control arm, but as i'm new to BMW, could someone please confirm (attached image)?

Also, i prefer to do my own maintenance and repair, but first time working on BMW, any pointers to a writeup or video on how to repair?

I was thinking to replace part then at least i can get it to an alignment shop.

Or am i simplifying a major issue?

Thanks,

[harshm235I]

Forgot to add details: 2015 M235I

[MarcoZandrini]

Go to www.realoem.com and enter the last 7 characters of your car's VIN. Hit enter and bookmark the page. Scroll down to front axle for part numbers.

[Dom147]

That's the lower control arm How did that even happen

the part number is 31106857329 for the left and 31106857330 for the right. You may as well replace both.

Replacing the control arms yourself is a good idea and very simple. Just make sure to torque while its on the ground and you should be good!

[harshm235I]

I have been reading up on the steps to replace the part.

One particular step has me confused. After installation of the new control arm, instructions are to "pre-load" or "pre-stress" to ride height using another jack before tightening the new arm.

My question is, if the car is jacked up, how do i know its ride height?

[Kernel Kurtz]

Originally Posted by harshm235I

I have been reading up on the steps to replace the part.

One particular step has me confused. After installation of the new control arm, instructions are to "pre-load" or "pre-stress" to ride height using another jack before tightening the new arm.

My question is, if the car is jacked up, how do i know its ride height?

I guess measure it first? You will want to use the second jack to raise the wheel so the spring is compressed and the wheel gap is the same as when it is sitting on no jacks, so that would probably be the best measurement to use.

[Dom147]

typically people measure ride height from the center cap to the fender line while the vehicle is on the ground. Then once you have to torque the control arm you raise the entire assembly using a jack to get those two points the same distance as before.

I hope that clears things up!

[harshm235I]

I am having issues matching/finding the part numbers. I found some parts on FCP Euro and Rock Auto, but the "interchange" or "OE" numbers dont match. Do they have to match exactly?

For example, the control arm bmw code is 31106857329, and on FCP euro i found lemforder 31126851259 but the description it says "OE number 31126851259" which is not the bmw part code.

Any ideas?

Thanks,

[Dom147]

It's the same. 31126851259 is just the code that lemforder uses for their database.

[M3SQRD]

Wow! I’ve never seen a control arm with its center section completely removed! What happened?

A more accurate ride height measurement is if you measure from the Aluminum lip of the wheel closest to the ground to the center of the wheel well. It’s more difficult to measure accurately, or repeatedly, from the center of the wheel cap. However, both approaches remove the tire section height, which can vary with pressure, from the height measurement.

[harshm235I]

It was snowing hard, must of hit some ice under the snow, bounced off the curb.

I know you cant tell just from an image, but do you all think i did more damage than just that arm? How can i tell if something major has bent or taken damage?

Spoke to a few car guys i know (hobby not pro) and they all seem to say get that part replaced and see how it drives.

[harshm235I]

Also, anyone know places to buy parts here in Ontario Canada.

[Kernel Kurtz]

Originally Posted by harshm235I

Spoke to a few car guys i know (hobby not pro) and they all seem to say get that part replaced and see how it drives.

Yup I'd replace the control arm and then take it to an alignment shop to get the full suspension geometry measurements. Go from there.

[harshm235I]

Changed the control arm, seemed to drive fine other than the wheel alignment comming off true, which i was expecting.

Found the braking system to be weak, thought it was becuase car was parked for 2-3 weeks.

I go to compare with the other side and find a cable missing from the braking system.

Looks electrical not Hydraulic.

No errors on the dashboard about braking system and i can select "sport+" and back to "normal" drive styles no issues.

Any idea of what its called so i can look into replacing?

Photos attached.

Thanks,

[harshm235I]

Here is the photo of the other side showing the cable connectivity.

[Dom147]

I believe that's normal. That little box would be open if anything was ripped out. I believe its some sort of wheel speed sensor that's only necessary for one side on each axle. The other wire that you see on both is for the EDC.

[harshm235I]

Thanks for all the replies team !!!!

Finally got both wishbone's replaced. Went for a test drive, i am hearing a humming noise.

I am assuming its the wheel bearing of the side that it the curb, but there is no play in the steering wheel or the physical wheel itself (did the lifting wheel of ground, 12:00 o'clock and 6 o'clock, then the 9 o'clock and 3 o'clock test, no play at all). Car handles fine other than wheel alignment out.

How can i confirm if its the wheel bearing?

If its not wheel bearing any thoughts on what it could be?

Thanks,

[Dom147]

Originally Posted by harshm235I

Thanks for all the replies team !!!!

Finally got both wishbone's replaced. Went for a test drive, i am hearing a humming noise.

I am assuming its the wheel bearing of the side that it the curb, but there is no play in the steering wheel or the physical wheel itself (did the lifting wheel of ground, 12:00 o'clock and 6 o'clock, then the 9 o'clock and 3 o'clock test, no play at all). Car handles fine other than wheel alignment out.

How can i confirm if its the wheel bearing?

If its not wheel bearing any thoughts on what it could be?

Thanks,

humming is probably due to the alignment being off