Let's talk front control arm bushings!

[Ape Factory]

Sexy topic. I know.

With all the weight over the front wheels, the front control arm bushings take a beating and they are known to prematurely wear causing the infamous suspension creak. I have the creak but only over slow, big bumps like sh. I was convinced it was the top mounts but now I'm not so sure. I'm hoisting the car up tomorrow and inspecting everything fully before making any conclusions or decisions.

Since I already have the plans (and parts) to replace the upper shock mounts with the 034 density line units, I'm thinking I'll upgrade the rest of the bushings while I'm in there and have things disassembled.

I **think** I've talked myself out of solid bushings. 034 has a kit and ECS sells them individually. Looking at $700 for just the bushings plus the lifelong increase in NVH on a daily-driven car. I've done solid once before, on my third gen RX7 track car. I didn't notice a huge difference in sound or vibration but it was already loud and set up fairly stiff.

So...that leaves me with a few options.

The easy button option© is to get the 034 density line lower control arm kit. I already have the Stern adjustable uppers so no need to get the full upper/lower kit. The kit already comes with all the necessary hardware as well. What I don't know is just how much firmer/harder their bushings are vs. OEM. I have the question out to them and I'm waiting on a response.

Second option is Powerflex. I really like this option. Two of the bushings are press-in and I sold my press before moving to Texas. So I'd have to get a new press. I can get them in street, or, what I'm leaning towards, race. I figure it's a step down from the full onslaught of solid bushings at half the cost but will yield a good percentage of what the solid bushings would gain in terms of minimizing deflection.

They're a UK company with a U.S. distribution division and I don't have widespread purchase options. I looked for a U.S.-based company but nothing really came up (unless I own a Camaro or Mustang). I know ECS does sell Powerflex but it doesn't appear they have anything in stock and the prices are the same as Powerflex directly.

I'd again have to press them in myself but it isn't that time consuming once the arms are out. The only downside is the 034's come with a heavy duty ball joints. I don't necessarily need them right now but if you're already taking everything apart, might as well, right?

Here's the Powerflex list of bushings needed (and they have rears too when it comes time for those).

Straight control arm
Front lower control arm bushing PFF3-701Bx2 $105.99
Front lower shock bushing PPF3-705Bx2 $108.99

Curved Control Arm
Front lower radius arm to chassis PFF3-702Bx2 $154.99

With the Stern upper arms, it looks as if their bushings are rubber. I'm assuming the OD is proprietary to the Stern arms and is not Audi "sized". I've got an email into PURE Motorsports to see if that's the case. I'd like to upgrade those while I'm at it.

[Sazexa]

I wouldn't rule out 034. I installed them because my factory bushings were beyond worn, they were shot. Anything above 65 MPH was dreaded vibration, and it made all sorts of noise. I bought 034's hole kit with new control arms and, bushing, joints, and hardware. It took maybe 4-5 hours to do on a lift, taking my sweet old time in no rush.

The controls introduced absolutely zero NVH, at least nothing I DIDN'T want. While they are double the stiffness of factory ones, the change these add was one of the more subtle to my car. They really aid in turn-in feel, and long-sweeping turn feel as well. As I said, I haven't noticed a bit of NVH.

034 says their rubber is "100% stiffer," so double the stiffness. But it doesn't translate to an uncomfortable ride by any means.

I replace my factory units at ~90K. I'll gladly buy another 034 kit in another 60-80K miles.

As far as control arms goes, I think it's only necessary if you plan a drop great than around 1.5" inches. Basically every inch lower translates to about 1 degree of less camber with these cars I believe. I've got a set of coil overs, and, before I install them I may look into a front adjustment kit. I'll assess my alignment figures afterwards and go from there. I believe the rear has more negative camber than the front by default, so, if the front isn't drastically throw out of whack, I may keep the uppers as they are. One last quick note on the subject as a general rule of thumb; camber is where the tire wears, toe is how quickly.

[Ape Factory]

I honestly don't know how much of camber the OEM control arms can compensate for. I would think zero since the OEM upper arms don't look like they're adjustable at all. Maybe an eccentric on the upright? Dunno...my last car was dropped less than an inch on Aragosta coilovers and I ended up killing a set of very expensive Bridgestones quickly. I believe I was at like .9" front and .75" rear. Had to go with front upper arms. I would say to include a set of adjustable arms with your suspension plans. I know it adds more cost but it'll be cheaper than a set of new tires in two months. I'd go for the Sterns or the SPC arms as they're adjustable on-car and no need to detach them at the ball joint/pinch bolt end.

My car is already on the Bilstein B16 kit with the Stern adjustable upper control arms. I'm assuming the Stern inboard bushings are simple rubber of OEM density/hardness so I was looking to upgrade those inner bushings. The outer are already solid ball joints. I read their description and it says it utilizes OEM bushings for the inboard side but I'm not sure on the inside diameter of the Stern arms.

I did not realize the 034's were 100% stiffer than OEM actually...they list it as a 65 durometer rubber but I don't know what the OEM bushings are rated at so there was no reference point.

As far as NVH goes, I figured the bottom control arms wouldn't introduce much NVH and I really wasn't that worried about it. But good to know on the 034's. They are my first choice mostly because it'll simplify the process.

And agree on the camber/toe. I'm running about 1.4 degrees all around currently. About as far as I want to go for a daily-driven vehicle. Tires seem to be wearing nice and evenly across the tread and I'm happy with mid corner/exit performance. Not 100% keen on initial turn-in just yet.

Anyway, I'll wait for a response from Pure MS and 034 before making a final decision. Power flex does have a durometer chart here: https://powerflexusa.com/howtochoose.aspx

Notice the purple bushings are 80A or 30% stiffer and "race" or black is 95A or 80% stiffer. Now we don't know what the reference is as I'm sure the OEM's use different durometer rubber.

BUT, if Powerflex and 034 (or whomever makes their bushings) are using the same scale to measure harness, then the density line, at 65A, is lower than the Powerflex street line (purple) bushings. That'd sway me towards the Powerflex stuff.

[Ape Factory]

Ok...popped both front wheels off to inspect everything. It's been raining almost every other day or days in a row for weeks so I ended up having to wash the suspension down to get a clear look. End result, I didn't see any torn bushings at all and no adverse play.

What I DID find is one bearing that was different from all the others. When I was in the process of trying to buy the car, they did mention a bad bushing had been replaced. He couldn't remember which one or get me more information. Well, turns out it was the driver's side leading upper control arm. I don't know why I didn't spot this earlier but it's a bit larger than the rest and doesn't look like it's positioned correctly in the control arm housing. I'm making an educated guess this is where the squeak is coming from.

Also had a response from Pure Motorsports, the inner bearings are OEM sized. So I can indeed replace them with the Powerflex bushings.

Looking at bearing/ball joint presses now to see what the total cost would be if I pressed everything out and in on my own. The lower curved control arm has a massive bushing on the inboard side.

I also sprayed the suspect bushing, and only that bushing with a bit of PB Blasters. I then took the car out to run errands. Guess what, zero creaking. I think I have my culprit. Time to order more nuts and bolts!

Will post photos later.

[Ape Factory]

Here's a pic of the offending bushing, first pic, with the passenger's side (correct) bushing below. It almost looks like there's an extra washer stuck in there. Never a fan of letting others work on my car. Too many bad mechanics doing what's easy and not what's correct.

[Ape Factory]

I've talked myself off the ledge. After investigating further, it doesn't appear it's a wise choice to use poly bushings due to wear issues on a daily driver. Ultimately that's what I'm trying to avoid. I may try a set on the upper control arms but I'm now leaning towards replacing the one offending bushing when I have the shocks out of the car. I've had zero noise from the suspension over the past two days. I'll take the extra money and do rear sway links instead. And when it comes time, I'll most likely go with the 034 lower control arms.

[red4life5]

I've talked myself off the ledge. After investigating further, it doesn't appear it's a wise choice to use poly bushings due to wear issues on a daily driver. Ultimately that's what I'm trying to avoid. I may try a set on the upper control arms but I'm now leaning towards replacing the one offending bushing when I have the shocks out of the car. I've had zero noise from the suspension over the past two days. I'll take the extra money and do rear sway links instead. And when it comes time, I'll most likely go with the 034 lower control arms.

That’s a good choice; I have them and support you there!


2010 A4 S-Line Prestige

[Ape Factory]

That’s a good choice; I have them and support you there!

What’s been your experience with them? Saw a lot of negative feedback in the RS4 section.

[red4life5]

What’s been your experience with them? Saw a lot of negative feedback in the RS4 section.

I like a stiff ride. I coded my steering to be very tight and I’m on Springs if that makes a difference. For the $400 price point on lower arms compared to the stealer-ship I will never look back. I haven’t heard of someone having a negative experience with lower ones. All the spherical link, upper arms crap is what everyone complains about


2010 A4 S-Line Prestige

[Ape Factory]

Oh ok I misunderstood. I thought you were referring to the poly bushings not the 034 arms. Understand now!

[Ape Factory]

Posted a bunch more info in my build thread but after diving into this today to change out the offending bushing, I discovered it was a poly bushing in there which was causing the squeaking. Looks like they're Powerflex black race bushings. Glad I didn't swap them all out for poly. The noise would have driven me crazy.