Control Arm Question
 

Hi, are Control arm and Knuckle the same thing? Have a 2004 BMW X5 3.0i and have to replace upper and lower control arms in the front. Was thrown off when the parts guy asked if I needed ball joints for the knuckles also.

I believe the knuckle is essentially the hub. The piece where the axle and arms connect to. The ball joints should come with the arms..... looks at ecstuning.com (sponsor) for your parts....that's what I did.

I think usually the ball joint comes with the forward lower arm. Ironically, was just e-mailing with my shop to see if the ball joints were replaced too this last spring when I had 'em do the arms.

Was also just going to post: Does anyone have a copy (or provide a link) to that really awesome wire frame picture of all of the X5's front suspension components? Actually, the rear too.

I came across that pic yesterday after researching a zillion posts, but now I can't find that one post. This gent's post is needin' the pic too.

Thanks guys!

I just ordered front lower control arms and ball joints, they are purchased separately. I believe the rear lower control arm comes with the ball joint.

Check out www.realoem.com they have all the diagrams for the parts. Don't go by their pricing though.

Here's the image you mean

http://static.bmwfans.info/images/epc/MTI3ODU5X3A=.png

Go to Welcome, BMW fans! for the original and many more.

The tension strut (no. 6) has separate balljoints (no. 15) that alot of people don't change, but which can also be the source of shimmys etc. The rear control arm (no. 10) has the balljoint built in.

I've had the shimmy (so to speak) since getting new tires. I'll be having the front lowers and ball joints replaced next week. I hope, hope, hope it fixes the problem. I chose to forego the rear arms because the shop didn't think there was anything wrong with them and heck...I'm not made of $$$.

I know you don't wanna hear this (I didn't when I was told) but it's almost undetectable levels of play that can make a shimmy. I changed my tension struts, then ball joints, then control arms, then tie rods - i.e. All done at separate times within a few days/weeks of each other. There was no play in anything while it was on the car except the tension strut bushes, but everything that was changed made some difference. Only after changing everything can I say I am shimmy free.

You will find once you take the parts off you will find some slop in the balljoints more than likely.

This is what I'm finding as well. Basically, plan on replacing everything with a rubber bushing or ball joint.. in 'waves', and be prepared to replace them all in order to get your X5 back to the way it used to drive new. The best thing to do is just keep of what you've replaced so far at each wave.

Yeah, unfortunately that's what I've heard. I figured I'd change the front arms and ball joints first. I'd love to do it all, but since I don't have the DIY skills, the cost is prohibitive to do it all at once.

You'll save on labour if you get the front stuff all done at once (once the wheels are off and they've got the tools out, its not much hassle to remove and refit all the arms etc.)

however I understand not being able to buy all the parts at once - without a doubt the parts are way more than the labour!

Just want to ad that replacing the ball joint only is really difficult. I tried to save a few bucks and go that route; it took an acetylene torch, big hammer, big vice, big pickle fork, and about 70 whacks before mine came out of the control arm. Buy the arm that has it pressed in already, it will have a new bushing as well.:thumbup:

The tension strut or the other control arm?

The tension strut is not sold with a bj pressed in, they are separate but you can put them together before you install it if you like to make it into a complete unit. Not much benefit though - they install into each other easily anyway.

As for removal of the tension strut, it can be removed with the bj attached - the bj is screwed into the wheel knuckle/hub with / screws, you can undo these without splitting the bj from the tension strut, then just undo the tension strut on the bushings side - no bj splitting required and then install new tension strut and new bj. HOWEVER you may fond the bj is seized inti the knuckle - with mine, got the 2 screws out just fine, split the bj with 2 blows of my construction sledge hammer (not met a bj yet that can resist this hammer) but the bj was siezed up there in the knuckle, not moving. In the end, it took a blow torch and air chisel to get out of it's little home.

As regards the other control arm, it is all one unit with the bj on the end and not available as separates, and on this one the bj threaded end goes direct into the knuckle, so it is not removable without separating the bj one way or another. Again, a 20kg sledge hammer with 2" handle makes it easy if you don't have the proper splitter.