These are the symptoms I get since a couple of weeks (08 2LT, 200'000km):

- Slight vibrations in the steering wheel above about 70 km/h, which come and stay for a couple of seconds, then vanish and eventually come again after a couple of seconds or so
- When downshifting (manual transmission) at higher speeds, I can feel a slight jolt in the steering wheel
- When breaking, I can sometimes feel a slight jolt in the steering wheel
- When lifting the foot from the braking pedal (at standstill) and releasing the pressure from the pedal, I can sometimes feel a slight jolt in the steering wheel
- When breaking at highway speeds, the car doesn't seem to break in a even line, but seems to have the tendency to veer in one or the other direction

We put the car on a lift for a quick check. Suspension seemed to be ok. Everything the mechanic tested and pulled and pressed on seemed to be tight (tie rod ends etc.). Brakes seemed to be ok from a visual standpoint.

The only thing we found was some rather noticeable tolerance/slackness in the steering wheel column's inner joint (meaning in the passenger compartment).

Could that explain all the symptoms?

 

You mean the steering intermediate shaft part number 25834100 and yes that could be your issue. If the inner u joint is loose you need to replace that shaft. Sadly 25834100 is obsolete and discontinued. Dorman has a replacement

 

Check the LCA bushings.

 

Also, again check the lower control arm rear bushings. Mechanics sometimes miss this very common problem. (I see Don beat me to it while I was typing. I would use that vid with caution. It takes some experience to read that test correctly.)

I like Oldblue’s steering shaft u-joint suggestion. It’s easily missed. Alone, shouldn’t cause all of your symptoms, but can unmask other problems.

 

Thanks for all your input!
Would that be the correct steering shaft?

 

Yes that’s it, after you remove that upper bolt, if the shaft won’t collapse, you can just cut the shaft to get the yolk off . Don’t pound on it , you might damage the steering rack or column

 

Ok thanks. Will order it and report back once it's swapped out.

 

Ok, so here's an update regarding this issue after having the Dorman intermediate steering shaft installed:

- SOLVED (even before replacing the shaft): Slight vibrations in the steering wheel above about 70 km/h, which come and stay for a couple of seconds, then vanish and eventually come again after a couple of seconds or so
-> I noticed that the rubber plug, which is held down by a screw to keep the airbox in place, had vanished (most likely rot away). Therefore the airbox was loose and seemed to have caused the vibrations (and about 0.5l/100km more gasoline consumption). I made a make-shift rubber plug out of some rubber sheets. Now the airbox sits tight again. No more vibrations and consumption immediately went down by 0.5l/100km. Maybe the vibrations also interfered with the combustion process...?

- SOLVED by replacing the shaft: When lifting the foot from the braking pedal (at standstill) and releasing the pressure from the pedal, I can sometimes feel a slight jolt in the steering wheel
-> the steering wheel doesn't jolt anymore when standing still

NOT SOLVED:
- When downshifting (manual transmission) at > 50kmh, I can feel a slight jolt to the left in the steering wheel, which initiates a very short, slight steering wheel shudder to both sides until it's centering again.
- When applying sudden break pressure when rolling forward (even at walking pace), I can feel a slight jolt in the steering wheel to the left. When applying gradual brake pressure, there is no jolt. When applying sudden break pressure when rolling backwards, there is no jolt, either.
- When breaking at highway speeds, the car seems to have the tendency to veer in one or the other direction ever so slightly with the steering wheel jolting very slightly.

All bushings, joints etc. in the front seem to be ok.
For testing purposes, we also removed the 60A EPS fuse to check the behaviour without the power steering motor. Even without the motor, the jolt was there.

As already pointed out in previous posts, could the remaining symptoms point to the lower control arm (although everything seems to be tight)? If yes, which side probably?
Or could these symptoms be caused by something else?

 

LCA rear bushings and possibly ball joints can cause those symptoms

 

When you roll up to a stop sign does it feel like the brakes are letting go a bit? Like as if the body moves forward but the wheel are not moving? That is the LCA bushings. Test as show in the video.