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      06-15-2014, 09:41 PM   #1
sipman
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Knock in steering that isn't bracing

Hi all,
I have a knock up front when I turn from side to side. I've tightened my strut to center bolts but no relief. Torque checked my wheel bolts and they are correct.

So any places to start looking? I'm thinking ball joints, maybe?
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      06-15-2014, 11:16 PM   #2
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I'm thinking ball joints too. Mileage?
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      06-16-2014, 09:58 AM   #3
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Sounds like sway bar bushings to me.

Audi has sway bars with a plastic coating that tends to delaminate and get stuck to the bushing, I don't know if BMW sway bars have the same tendency. The sway bar bushings could be sticking either way.

Easy check, hit your sway bar bushing with some thick grease from a grease gun.

You have like 30-40k miles right? Sounds too low for ball joints to fall, unless you got a defective one. Probably something rubber that failing from age instead of miles.



note: did you torque the brace to strut bolts as well, or just brace to center? mine was loose on the strut dome end when I caught it.
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      06-16-2014, 01:29 PM   #4
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Quote:
Originally Posted by jdoublehcubed View Post
Sounds like sway bar bushings to me.

Audi has sway bars with a plastic coating that tends to delaminate and get stuck to the bushing, I don't know if BMW sway bars have the same tendency. The sway bar bushings could be sticking either way.

Easy check, hit your sway bar bushing with some thick grease from a grease gun.

You have like 30-40k miles right? Sounds too low for ball joints to fall, unless you got a defective one. Probably something rubber that failing from age instead of miles.



note: did you torque the brace to strut bolts as well, or just brace to center? mine was loose on the strut dome end when I caught it.
I had one of these noises too and it was loose swaybar endlinks... Check those.
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      06-16-2014, 06:11 PM   #5
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Thanks all. Mileage is approx 24k.
I'll check both. Is there a good method to check balljoints and links? I'm hoping if it makes noise, there is enough wiggle room for me to discover the culprit by hand but if not, is there an established method?
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      06-16-2014, 07:04 PM   #6
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Check your control arm bushings... There is a possibility that they are causing the knocking.
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      06-16-2014, 08:48 PM   #7
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There's a gauge thing bmw uses to apply pressure using a screw and see if it moves, but I don't think its easy to use or widely available. I usually just pull on mine to see if I feel any slack, and maybe throw a wrench on it to make sure the nut is tight.

You could also try having someone turn the wheel (while the car is stationary) while your head is close to the wheel, and see if you hear it pop. Then try the same thing with it in the air and the suspension unloaded. Not sure if you'll replicate the loading accurately enough, but it might work, and it would help you narrow it down a lot more. I think I'd start with that before you take anything apart.
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      06-16-2014, 09:01 PM   #8
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I torqued the inner and outer, but I haven't torqued the cross brace. I'll start the official investigation this weekend
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      07-26-2014, 07:35 AM   #9
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OK, The sound has progressed, and the culprit still eludes me.
I put the car in the air yesterday and pushed, pulled, banged, etc and can't find the cause of this.
Basically, if I go over a rough (Philly roads rough) section with mainly the passenger wheel, the suspension sounds like it belongs on a taxi.
When I drive over smoother undulations, and bumps, no noise. This is with either wheel or with both.
But if I drive over one of those "speed bumps" that gets formed on the highway from expansion. You know, where it's like a line of asphalt about an inch or two tall that spans the entire width of the lane, and the two front tires kind of hop over them. Then the noise seems to be from both sides.
So basically, it seems that when either wheel's motion is well controlled and damped, then no noise of if the tire is following the road and never looses contact.
But if the suspension is forced to quickly extend and the stop suddenly, like driving over one of those 'speed bumps' or driving over one of the patches of road where the road is broken it makes noise.
Does that make sense?
I banged with a hammer on ever part, and the only noise i could make, besides the splash shield rattling, was maybe in the upper sway bar joint. But in twisting, it felt tight. Otherwise, I'm at a loss.
Also, I checked my engine mount bolts and they are all still tight.
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      07-26-2014, 08:19 AM   #10
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I had a knock up front and it turned out being the sway bar end link nuts were loose.
If you have adjustable end links they may have worked there way out of adjustment if the jam nut was not tightened.
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      07-26-2014, 02:57 PM   #11
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A little confused, you started the thread saying the noise happens when turning from side to side. Does this still produce the same noise as when the front end is subjected to a sudden bump or rough section?
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      07-26-2014, 08:13 PM   #12
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Yeah. I don't think I did a great job diagnosing the noise as it was so fresh. Turning the wheel while car was stationary does nothing. And I can't get it to make the noise in small turns but I think in strong changes of direction when the weight of the car shifts it will. But to be honest, I've really been focusing on the noise from the sudden bumps
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      07-26-2014, 08:21 PM   #13
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Have a friend drive your car and ask them to tap the brakes. Do the wheels move back a lot? That's a typical FCAB failure.

Try driving up a driveway at an angle. Does one side make the sound more than another?

I had a hell of a time finding a bad ball joint in my e39 m5. The knocking sound you described is identical, however. It was the tie rod ball joints and they only knocked when hot.
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      07-28-2014, 12:48 PM   #14
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Hey Jason.... I would check your motor mounts/bolts. The sound you are describing sounds like my car did when the bolts broke. It was only over "humps" when the motor would bounce up due to the sudden force of the bump and then slam back down that I would hear the noise.
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      07-30-2014, 03:08 PM   #15
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You're thinking mount to engine bolts, right? Or did the bushing in the mount fail, and it makes that noise?
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