Front lower control arm replacement

[t44tq]

I tried searching but didn’t find anything relevant.

Are there any tricks or suggested ways to remove the 21mm bolt from the top of the subframe securing the control arm? I can just barely get a box wrench on the bolt, but I think it’s just spinning. I don’t really see how to make enough space to get the 6mm Allen wrench on the bolt and a 21mm wrench on the nut to get it loose.

Do I need to remove the sway bar to make more space?
it’s very tight in there. Any suggestions? Thanks!

This is on a ‘02 M3 if it matters.

[Tbonem3]

Pickle fork or some other seperator type of tool with a long lever like a pickle fork, or something that derives its leverage from a screw action (hex head). Bathing it in PB/liquid wrench ahead of time or hitting with fire would help, but maybe not fire since there's a rubber boot, and the top is inaccessable I think.

Getting the nut off was the easy for me. I have a 1/2" drive flex head.

[eacmen]

Are you talking about the inner bolt? Should be pretty straight forward.

Might be a useful video:

https://youtu.be/35U7INZPDqg

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[toy4to]

This is also a very good video.

https://youtu.be/usfbSLE_1aI

[sapote]

I can just barely get a box wrench on the bolt, but I think it’s just spinning.

If the ball joint spins then place a floor jack under it and jack up a little to press the tapered shaft tight and it should not spin. Once the nut is off, use a large fork to separate it from the frame.

[t44tq]

Pickle fork or some other seperator type of tool with a long lever like a pickle fork, or something that derives its leverage from a screw action (hex head). Bathing it in PB/liquid wrench ahead of time or hitting with fire would help, but maybe not fire since there's a rubber boot, and the top is inaccessable I think.

Getting the nut off was the easy for me. I have a 1/2" drive flex head.

Not the ball joint at the suspension upright, the big nut on top of the subframe.

[t44tq]

If the ball joint spins then place a floor jack under it and jack up a little to press the tapered shaft tight and it should not spin. Once the nut is off, use a large fork to separate it from the frame.

Again, not the ball joint at the suspension upright- that one is easy. I’m talking about the big bolt that has a 6mm Allen in the center and takes a 21mm nut, on top of the subframe. Very limited access due to the sway bar, power steering lines, etc.

[eacmen]

Again, not the ball joint at the suspension upright- that one is easy. I'm talking about the big bolt that has a 6mm Allen in the center and takes a 21mm nut, on top of the subframe. Very limited access due to the sway bar, power steering lines, etc.

The inner ball joint is a tapered shaft ball joint. So putting a jack underneath it will push the taper into the subframe locking it into place.

I've been able to get an allen and a wrench in there, just need to get creative. I think I got a stubby allen and let it spin until hitting something so I didn't have to counterhold it myself.


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[bigjae46]

I just make my life easy...drop the front subframe. And really no way to torque the inner bolt with the subframe in the car. Also a good time to inspect the engine mounts.

Shameless plug - I have a pair of OE mounts if you need some.

[Slideways]

Craftsman 1/2" Drive Flex Head Quick Release Teardrop Ratchet with a short socket. To counter hold the ball joint, one of the reinforcement plate bolts can be threaded in from the bottom of the ball joint if I remember correctly.

[sapote]

Again, not the ball joint at the suspension upright- that one is easy. I’m talking about the big bolt that has a 6mm Allen in the center and takes a 21mm nut, on top of the subframe. Very limited access due to the sway bar, power steering lines, etc.

Only ball joint that has the 6mm Allen hole; why a normal bolt needs the Allen head?

[t44tq]

Craftsman 1/2" Drive Flex Head Quick Release Teardrop Ratchet with a short socket. To counter hold the ball joint, one of the reinforcement plate bolts can be threaded in from the bottom of the ball joint if I remember correctly.

If threading the plate bolt from underneath works, then I'm golden- I'll try that, thank you.

[t44tq]

The inner ball joint is a tapered shaft ball joint. So putting a jack underneath it will push the taper into the subframe locking it into place.

I've been able to get an allen and a wrench in there, just need to get creative. I think I got a stubby allen and let it spin until hitting something so I didn't have to counterhold it myself.


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After reading this a couple times, now I understand what you're talking about- again, I'll try it. Thank you.

[t44tq]

Only ball joint that has the 6mm Allen hole; why a normal bolt needs the Allen head?

Sorry- I didn't get what you were talking about until eacmen explained it to me- thank you.

[bimmerfan08]

Check out my rod bearing DIY in the DIY section. I cover front suspension refresh, too.