1995 A6 suspension knock with steering turn

   #1  

stabes

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Hello all,

For years my dad has lived with this irritating klunk every time he turns the wheel. It drives me mad!
Have taken it to a few people who tell me that the spring is rotating inside its housing, which causes the loud klunking sound when the wheel is turned - probably because it's lost some tension.
BTW, it doesn't matter which way the wheel is turned. Usually worse when turning full lock to the right. All rubber grommets etc apparently okay. Doesn't do it when weight of car is lifted off the wheels.

Anyone heard of this?

Mart
 
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AIB Wolfgang

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Hi Mart,
there is a ball-bearing under the upper plate of the MacPherson strut. You have to remove this.
 
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stabes

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Hello Wolfgang,

A ball bearing? Just one ball bearing? I presume I need to replace it?

Mart
 
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Uwe

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I agree with Wolfgang; it sound like it's time to replace the upper strut bearings.

Personally, if the struts themselves are original (20 years old), I would replace them too while I had it all apart.
 
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DrPeter

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Hi,

A ball bearing? Just one ball bearing? I presume I need to replace it?

Google (image) this part number [4A0412249], that should be the bearing.
- It fits between the upper Spring Perch and the bearing plate.

- You will need refer to the factory repair manual and a proper spring compressor to replace it... (Be careful!! - lots of spring tension)

- And Uwe is right, might as well replace the struts and add the upper strut mounts.

Google this part number too [4A0412377C] - should be the Upper Strut Mount

- Please check with the dealer for the correct part numbers, I am not a parts person and I could be wrong about the part numbers that fit your vehicle! I provided them just for illustration purposes.

Hope this helps,

drpeter
 
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stabes

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Thanks all. I replaced the upper strut mounts about three years back hoping that would cure the knock, but it didn't.
In a nutshell, it seems unlikely that it would be the spring causing this - having lost its tension over the years.

Mart
 
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DrPeter

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Thanks all. I replaced the upper strut mounts about three years back hoping that would cure the knock, but it didn't.
In a nutshell, it seems unlikely that it would be the spring causing this - having lost its tension over the years.

- Can you isolate where the noise is coming from? If you lift the front end off the ground (front wheels off the ground) and attempt to recreate the concern, does the noise go away or change?

Have you:
- Replaced the control arm(wishbone) bushings?, Front sub-frame bushings?
- Re-torqued all the front suspension components, including the steering rack, wheel hub/bearing bolts?


drpeter
 
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stabes

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Only happens with the wheels on the ground. I have looked at the spring while the steering is turned and at certain points, and when the knock happens, the spring seems to stick instead of moving smoothly with the wheel rotation.

Mart
 
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Dana

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If you do not have access to a drive-on vehicle hoist (like an alignment machine, where turntables are used to leave the suspension loaded) you might try a lube. Perhaps a heavy soap and water mix to spray in a specific area and see if the noise issue can be isolated that way.
 
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El Polaco

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I agree with trying to isolate the noise by using a drive-on rack or something that keeps the suspension loaded. I remember seeing a lower ball joint on a 996 that had a "klunk" when the wheel is turned past a certain point. You can try to put a long screw driver or wooden dowel, don't use fingers, against parts in question and see if you can isolate where the noise is coming from while someone turns the wheel. I don't think I agree with the coil spring loosing tension. If you have ever assembled a strut on these cars, there is plenty of compression on the spring before the weight of the car is even added to the mix. Let us know what you find.

j.
 
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stabes

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Thanks everyone for the input. Will pull this thing apart in the next few weeks.

Mart
 
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