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How to remove stock caster arms?

spaghettihoes

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I'm trying to replace the caster arms with Verklines but can't figure out how to undo the bolt that attaches to the subframe as the clearance is pretty tight. Do I just get a wrench in there or a swivel attached to a socket?

Hopefully someone who has done SPL caster bushings or the Verkline arm can share their experience.

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ubframe.
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razorlab

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Through the front with socket. Easier to take the bumper off but doable with it on. Watch your knuckles.
 
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spaghettihoes

spaghettihoes

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Through the front with socket. Easier to take the bumper off but doable with it on. Watch your knuckles.
Thanks that helped a lot, managed to get it off.

For anyone trying to do this in the future a deep socket, small extension and swivel worked enough for me to barely get a torque wrench in there without taking off the front bumper.
 

tracer bullet

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@spaghettihoes - Curious if you were happy with the new arms?

It's on my short list of things to do to my Z4 to try and gain a little bit of actual road feel through the steering wheel.
 

Z4m40i

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It’s the bushings that give the feel and they do make a difference.

in the first video you can see how the steering wheel shimmies under straight line braking, and the 2nd video you can see how the steering wheel almost snaps in trail braking. The bushings pretty much removed this.

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IMG_5076.webp



 
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tracer bullet

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For sure, removing the extra rubber, is why I'm interested. Glad to hear another backup them making a difference, thanks.

Installation not too bad? I've done springs / struts / control arms / tie rods / etc. a few times on other cars. Looks like access here is a royal pain but I'm able to get the car safely on stands and do have a variety of impact sockets and extensions, including a swivel, even if I can't fit the actual impact up there to use. The Z4 is totally rust free and not very old so I don't expect too much of a fight. I can borrow a ball joint popper, too.
 

Z4m40i

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Updated my comment with videos to demonstrate the issues with stock bushings.

Removing the arm is really straight forward, just need to remove the under panels to gain access.

All the arms are tapered fit so they all should drop out without hitting/pressing after unbolting the 21mm nut at the ball joint. The 13mm is a little hard to access- you’ll need a few extensions and a swivel. I’d recommend purchasing the bushing pre installed if you don’t have a press since the bushing is HUGE.

access at the green X
IMG_5364.webp
 

razorlab

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Updated my comment with videos to demonstrate the issues with stock bushings.

Removing the arm is really straight forward, just need to remove the under panels to gain access.

All the arms are tapered fit so they all should drop out without hitting/pressing after unbolting the 21mm nut at the ball joint. The 13mm is a little hard to access- you’ll need a few extensions and a swivel. I’d recommend purchasing the bushing pre installed if you don’t have a press since the bushing is HUGE.

access at the green X
IMG_5364.webp
That's not a photo of your actual Z4 right? It has the EU aluminum aux radiator mounts.
 

Z4m40i

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Nope, good eye. Just a quick google search for a photo to illustrate the access point.
 

tracer bullet

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It's funny that I already downloaded the exact same phots and have been staring at them. I was like "woah that was your car I was looking at earlier"?

Also, thank you!

I have access to a press, but I don't think there's many if any sleeves with it, will have to check on that. Thanks for showing the part numbers if I go that route.
 
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spaghettihoes

spaghettihoes

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@spaghettihoes - Curious if you were happy with the new arms?

It's on my short list of things to do to my Z4 to try and gain a little bit of actual road feel through the steering wheel.
I've been happy with them, Verkline definitely makes quality parts.

I didn't track the car before I put the arms on so I can't speak too much on the performance side other than spirited driving but to be honest I didn't notice any difference in ride quality or feel after I changed them. They just allow me to align my car's caster.

The install was a bit of a pain in the ass. As highlighted above, one of the main bolts goes through the subframe and I needed a ton of extensions and swivels to get a torque wrench on there. Other than that it was pretty straight forward. I didn't need to take the bumper off but it would have definitely made it easier. No need for a ball joint popping tool either.

The bolts are also one time use so you'll need to order replacements from BMW or Toyota. They're torque to yield so you need to stretch them by turning them a set amount after torquing them to their ft/lb spec.
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