Dumb Question - Strut Mount Rotating?

[benzor]

So in the process of doing my PS pump rebuild, I was turning the wheels lock to lock with the car off the ground. I heard a strange creaking noise progressively.

Turns out the springs were turning, and the rubber at the top of the strut mount. Here's a shot of the distorted mount.

So here's the question: should this be happening? I figured the ball joint was supposed to take most of the rotation of the wheel.

[Arthropraxis]

No, that should not happen. Check your steering rack bushings. Get someone to turn the steering wheel lock to lock while you look from under/beside the car at the steering rack, with the car on the ground. If the rack moves it needs new bushings.

[968 GUY]

There is a bearing encased in the upper mount.
Not 100% sure,but your upper mount may be toasted.

[benzor]

OK, will take a look for rack movement tonight.

968Guy, any thoughts on checking the upper mount? I figured its not the singular cause of failure, because if the bearing failed, that wouldn't explain the spring's rotation as well?

[968 GUY]

I believe the upper mount is the pivot point for the mcpherson strut.
That's why the spring and the strut rotate along with the spindle.
I THINK I'm right about this.

[benzor]

OK, will take a look at that too.

[mhr]

It definitely does rotate and the twisting of the rubber may be exaggerated because with the car in the air there is no load on the strut pushing it up into the bearing. That said if you are hearing allot of creaking or popping the bearing may be shot. Would not be surprising I had to change mine on my 91 S2 with 90k.

[benzor]

So I took a look at the rack - it is not moving, so looks like the 2 bushings are ok.

The strut mount bearings are not groaning, but they are rotating. Here's a video. Sounds like consensus opinion is that this is not a problem?

Strut mount rotating - YouTube

[mhr]

Looks normal to me

[Rasta Monsta]

The answer is yes, that is how the suspension is designed. There is a sealed bearing in the upper mount that rotates (with the strut, spring, and spring hat) when the steering angle changes.

[Arthropraxis]

I have late mounts, mine don't twist like that.

[924RACR]

Yes, they should rotate. That's why there has to be a bearing in there. Common to all strut cars.

I agree with what's been said about the groaning.

I've gotten the impression that you can evaluate the age/wear/sagging of the strut mount by the amount the "hat" is deflected up from the plastic lip on the top. The picture in the thread doesn't look too bad, I've seen some that really deform quite a bit...

[benzor]

Thanks guys. Taking it in for an alignment today!