I finally got around to editing my front control arm video.
I replaced the bushes on both sides with poly bushes as the rubber ones had disintegrated and the suspension was knocking. I took it for an alignment afterwards and it didn't need any adjustment at all.

100k miles in and my lower arm balljoint was absolutely perfect also. Here's how I did it.


I was keen not to bin the old control arms as they're only cast steel and the aftermarket ones look like pressed steel which I don't think is as good. There's not really a lot to go wrong with them, only the balljoint. In my case the balljoint was absolutely fine.

 

How does it ride with those bushings?

 

So far, absolutely perfectly.

 

thanks for responding! Do you notice any additional harshness?

 

Hard to tell really as the old bushes were shot when I bought the car, so I don't know what good feels like.

I wouldn't say the car is crashy any more than I would expect from a Porsche.

 

I'm going to swap the to Q7 Aluminum Control arms, I already have a new set. Just trying to decide if I'm going to press out the new bushings for Poly or just run them for a while.

 

It's 2026. Aren't polyurethane bushings known to be the performance enhancing equivalent of 1990's FartCan exhausts?
Like, don't they literally do zero of the things properly that are required from rubber bushings?
I never used them, but I didn't think they were a thing anymore.

 

Yes, they are the exact equivalent of "FartCan" exhausts. Same in 2026 as in the 90's.
Increased stiffness and NVH compared to stock bushings and all the benefits and downsides of that. Same as "FartCan" exhausts increased performance (if done right) AND noise.
I use them and they perform as expected.

 

While we're on the subject, what's the thinking as to torquing up the bolts with the wheels on the road.
On the e38 BMW, the manual said you had to only torque them with the vehicle in the "normal position."
They even wanted mechanics to put 80 lb weights on the seats to simulate passengers.
Do the stock mating surfaces lock up after torquing? Seems like they would, but then again..

 

Never mind, Grok convinced me.
I guess it's not explicitly mentioned in the service manual since an alignment would be done, and alignments are done with the wheels down.


Why This Matters

These are suspension components with eccentric bolts (for alignment) and bushings that need to be torqued in the loaded (normal ride height) position. Torquing them with the suspension hanging (e.g., on a hoist or jack stands with wheels off the ground) can preload the bushings incorrectly, leading to:

• Binding
• Premature wear
• Vibrations or noise
• Alignment issues

Standard Procedure (from FSM and multiple confirmed DIYs)

1. Install the new lower control arm and loosely hand-tighten or lightly torque the bolts (including the strut/fork connection and inner eccentric bolts).
2. Reinstall the wheel (if removed).
3. Lower the vehicle fully to the ground so the suspension is at normal ride height with the full weight of the car on the wheels.
4. Final torque the bolts to spec (typically with the car on level ground).
   

Common torque values (verify with your specific manual or a trusted source like the Rennlist PDF attachments, as they can vary slightly by exact part/revision):

• Strut to lower control arm fork: Often ~111 ft-lbs + 90° (or similar; one common value is 150 Nm / 111 ft-lbs + 90°).
• Inner control arm bolts (eccentric): Around 170 Nm / ~125 ft-lbs or per spec.
• Ball joint pinch bolt or related: Check exact values.

Practical Tips from Owners

• Many people lightly tighten everything on the hoist, lower the car, then do final torquing.
  
• If you can't easily lower it (e.g., alignment rack), jack under the lower control arm/ball joint area to compress the suspension to approximate ride height before torquing.
  
• Get an alignment immediately after—don't skip it, as these bolts affect camber/toe.
  

This is standard practice for most vehicles with rubber-bushed control arms (including related platforms like the VW Touareg/Audi Q7). Following the FSM avoids comebacks like vibrations that some owners have reported when torquing in the air.

 

For stock bushings, yes.
For poly bushings, doesn't matter as they're not bonded to the inner and outer sleeves. That's why they get greased up during assembly - bushings rotate freely, unlike stock type bonded rubber bushings which will spring the wrong way if installed incorrectly.

In reality, not sure how much benefit the e38 procedure really adds. You need to get them close, yes. But, if you have air suspension and drive in the "Low" position all the time like many do, then technically your bushings are always under "wrong" tension, as they were tightened at "Normal" height. So I'd say no need to go crazy during install.

 

My alignment shop ask whether I mostly drive by myself or with someone in the car and my weight. They set the ride height with weight in the car. When I do the suspension, thankfully I do have a drive on car lift in my shop, I do set my cast iron weightlifting plates in the drivers seat and floorwell when I torque up the bolts. Every car manual I have ever seen says the suspension should be tightened/torqued with the car weight on the suspension.

 

Makes sense. Yeah I actually bought two bags of sand from the Home Depot years ago.
Just didn't remember any mention of the practice on this board.
I think it was more critical with that squirrely BMW design. If you just looked at those bushings the wrong way you'd develop a shimmy that got progressively worse.
I used Powerflex bushings in the e38. The Cayenne design is so much more robust and stable IMO.

 

Probably wouldn't have to worry about having the weight on the suspension with Powerflex in the way the bushing moves. But with rubber bushings picture locking the rubber in with the suspension drooped, then you lower the vehicle and the suspension settles and the bushing now has a twist in it. So it will spend most of it's, shortened, life under a twist/stressed position instead of and unstressed position so it wears out much quicker.

 

Hi. It's 2026. Aren't comments like yours which are uninformed known to be unproductive in a conversation concerning the main topic of this thread. They are very much a thing still, not only aftermarket, but on certain GT-cars and overlanding Cayennes, or for those who may want a more firmer and less compliance or cushy ride, so to speak. What does 2026 have to do with anything? The unsarcastic response to your inquiry is No and No.