OEM Struts

[S4Mon]

2012 S4 with 144K miles.
I'm still riding on the original struts and I'm not sure how to tell if they are worn out. There is no oil leakage on the tube's, no wet areas. I don't notice any bouncing when going over bumps. The car still has its sporty feeling, not a super comfortable ride. Should they be replaced anyway simply because of the mileage?

I see cars on the highway all the time where one wheel is bouncing like crazy from a blown strut but do Audis do that if there is a bad strut?

[Smac770]

The only way to really tell they are worn out is to dismount them and see if you can play them like an accordion easily, or properly bench test them. Their job is to resist movement, so if they can be moved easily, they are no longer doing their job. I replaced mine when I noticed what I felt was excess rear body roll in a sharp corner, compared to the vehicle movement taking that corner in the past. Once I got them out, there was no resistance going on. The fronts were not that bad, but clearly not like new. But I never noticed excess wave motion after a speed bump or such. I did mine at 160k.

I guess the idea is do you plan to run the car much longer? If so, it won't really matter if you do the dampers now or later. But if the question is "can I get 20k more out of this before I dump it without replacing dampers", if there's not an issue you're trying to solve, why bother spending the money.

[LowKeyLoki]

Dude 12 years and 144k miles, just replace them. Especially if they are not the ridiculously priced ADS struts. If you are about to get rid of it soon then maybe don’t but if you are keeping it longer then definitely replace them.

[DrGrapeApe]

All of mine were toast at just under 100k miles. I could compress all of them by hand and the rears would come back slowly, the fronts wouldn't come back at all. No signs of leaking fluid, the only indication I had that they were done was a very slight jostle over expansion joints on the highway.

[S4Mon]

Thanks for the responses all. I'm assuming I'll need an alignment if I R/R all 4 struts, correct?

[LowKeyLoki]

Thanks for the responses all. I'm assuming I'll need an alignment if I R/R all 4 struts, correct?

For sure

[Nillious]

Simply pressing on a damper can’t really tell you how worn it is unless it’s really bad. My oem dampers felt perfectly fine when I removed them at 90k. When I actually drove with the new ones it was immediately obvious they needed replacing. I didn’t even drive a mile before I noticed the increased control of motion in the car.

[S4Mon]

Can worn out struts cause the steering wheel to shake when at highway speeds (>55mph) or is this more likely to be caused by imbalanced tires up front? Even though I just had them balanced at Tire Discounters a couple weeks ago.

[B72.0T]

Can worn out struts cause the steering wheel to shake when at highway speeds (>55mph) or is this more likely to be caused by imbalanced tires up front? Even though I just had them balanced at Tire Discounters a couple weeks ago.

Worn struts can definitely cause shake and instability at higher speeds, happened to my former B6 A4. Mostly noticed around 70-80mph.
On another note, I too am sort of in the same boat as you, 2012 here with 128k miles, on stock struts/all suspension components. Car drives fine and no shaking during driving, but I did develop more of a rougher idle as of late. I believe it is time for new motor mounts. Soon after that at some point I will get struts and all control arms replaced.

[S4Mon]

Also do I need to replace all 4 springs as well while I'm in there? I wish they sold Bilstein B4 strut/coil springs already pre-assembled to simplify the whole process.

[B72.0T]

Unless upon inspection you find cracks and/or missing pieces to your springs, and unless you are planning on lowering your car, there is otherwise no need to replace your springs.

[S4Mon]

I do not want to lower the car so hopefully they are in good shape. I am not seeing any difference in ride height either.

There is an ebay listing for a Bilstein B4 front/rear strut kit with new mounts/boots for $515 shipped but it says the kit fits B8 A4 and B8 S4. Does that sound right?

[Smac770]

What's the Bilstein p/ns? Either they are the correct ones for your vehicle, or they are not. "B4" alone is not sufficient to confirm application.

While Bilstein has B4 p/ns for A4 1BA and A4 1BE, for the S4 1BD, Bilstein is going to direct you to their B8 monotube dampers. 1BE and 1BD are the same ride height, but the Sachs dampers for 1BD are likely "more sporty" than the ones for 1BE.

S4: https://cart.bilsteinus.com/catalogue?VehicleType=Car**Truck**SUV**Van&Year=2012&Make=Audi&Model=S4&SubModel=Base&performancelevel=Performance%20Level%202&category_id=1&catname=Shocks%20%26%20Struts
A4: https://cart.bilsteinus.com/catalogue?VehicleType=Car**Truck**SUV**Van&Year=2012&Make=Audi&Model=A4%20Quattro&SubModel=Base&category_id=1&catname=Shocks%20%26%20Struts

The B8 are normally targeted at a lower ride height than stock 1BD. But I guess they figure B8 matches the 1BD ride height closer than B6 (which is what I have on my 1BA A4 these days).

1BE and 1BD are the same springs. If you're not interested in the sportier dampers, or the much increased cost for B6/B8 front struts, the B4 sport dampers will work just fine. But you need to make sure they are the B4 sport p/ns, not the B4 standard p/ns.

[Nillious]

I used the b4 sport dampers on my 13 s4. Go with the b6 or b8 dampers. The b4 is underdamped imo. This is probably why the b4 is not a suggestion from bilstein. I went against the grain looking for better ride but ended up with too much chassis motion over uneven roads.

[S4Mon]

Thanks for the input Nillious.

I noticed something yesterday during my commute and the steering wheel shaking. Yesterday morning (low 70s) my steering wheel did not shake at all and in the afternoon (low 80s) it did not shake at all.

Thursday morning (mid 70s) it did not shake but coming home from work it was shaking moderately the whole way on the interstate. It was very hot outside, 102 F.

Can very high ambient temps affect something on the car to make the steering wheel shake? I replaced all the front control arms recently with Meyhle HD. Also replaced the front passenger CV axle, inner and outer tie rods.

[LowKeyLoki]

Check your tire pressures and check for uneven wear or run out or cupping etc.

[S4Mon]

All tire pressures are at 41psi. What is run out in tires? I don't see any cupping. How can driving the same road a day apart produce different results? Strange

[LowKeyLoki]

41 psi cold is kinda high, I think most people run 36psi cold. Did you replace suspension components already and or steering linkages? Bad ball joint on control arm or tie rods will cause vibration at speeds above 45-55mph
And run out I just meant uneven wear inner vs outer tread on the tire

[S4Mon]

41psi cold is what is printed on the door jam sticker for 19" wheels.

I have all new control arms up front (drivers/passenger). A new CV axle, inner and outer tie rods on passenger side. New rotors/pads since April (no shaking when braking, also the wheel spins with no rubbing when car is jacked up).

[S4Mon]

Tire wear looks fairly even across the tread surface. I don't have a tread depth gage but I'm not seeing a noticeable difference between the inner and outer sections.

A guy at Tire Discounters said my tires are cupped when he ran his hand forward and backwards across the tread. Maybe my struts are worn out and messed up my tires?

I'm shopping for Bilstein B6s...

[DrGrapeApe]

The door sticker is deceiving, it's 41psi in all tires if you're at max load. In the owners manual it'll list lower pressures for normal loads.

[S4Mon]

Oops I've been running 41 for the past 9 years lol. Honestly I've never seen excessive wear in the center

[Nillious]

I run 36 rear and 38 fronts. 41 all around gave the car a very nervous feeling around corners almost like oversteer. Car is very planted feeling at the lower pressures.

[S4Mon]

Nice, I'll check my owners manual and adjust accordingly

[evanb]

I run 36 rear and 38 fronts. 41 all around gave the car a very nervous feeling around corners almost like oversteer. Car is very planted feeling at the lower pressures.

It may depend on the tire as well. I run 40psi all around on PS4S' and it doesn't feel nervous at all.

[S4Mon]

My steering wheel hasn't shaked at all this week, strange.