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#1
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Tapping noise from the rear
I crawled under the car to look and noticed the heat shield of the exhaust in the rear was missing three fasteners and it was hitting the exhaust and the driveshaft. Put it back in place and went for a test drive and it seemed that the sound was not so prominent anymore but it was still there. Could have been just a coincidence though. Also inspected the CV boots in the rear and they all seemed to be intact and dry, no grease anywhere to be seen. Also haven't noticed any vibrations when driving the car. I feel like it still could a bad CV axle, I guess they can go bad without having a torn CV boot but anything else to look for before I take the car to an indie? I will also do an another test drive today and let the wife drive the car me staying outside trying to pinpoint the location of the sound.
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09/2003 X5 3.0i 02/2003 X5 4.6is (non-runner) |
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#2
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Tapping noise from the rear
If the sound is very metallic and a clean sound would almost describe as "tink tink tink". It's almost surely lose bolts in the GIUBO.
If it's giubo you can usually reproduce with the car in neutral and drive wheels off the ground and rotate the wheels= driveshaft. It makes a distinct "tink" sound typically once or more per revolution often at the same spot so make a mark and watch it. I looked (but no luck) for a YouTube video that I used as reference that was almost identical to the problem I fixed. I only had to re torque the six bolts to spec and the problem went away. Hope it's as simple for you.
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2011 E70 • N55 (me) 2012 E70 • N63 (wife) |
#3
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Also: do the math on the frequency; drive shaft turns 3.9 or 4.1x per wheel revolution.
2.225m=7.3 ft per revolution on the wheel. CV will usually cause sound 2/3x per rev
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2011 E70 • N55 (me) 2012 E70 • N63 (wife) |
#4
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Quote:
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2003 BMW X5 3.0i -- MT5, 3.64s final gears, H&R lowering springs, K-Mac bushing kit 2007 BMW X3 3.0Si -- MT6 |
#5
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Okay after another test drive I can quite surely say the sound is coming from the passenger side rear wheel area, so I guess that rules out the giubo. Also filmed a short video of the sound where I accelerate from the stop to about 25 mph (40 kmh). As you can see the noise fades away when the speed increases and comes back when I let off the gas and let the car slow down. With a tape marking the spot, I was able to see that the noise occurs usually once per revolution of the wheel.
https://youtu.be/WfXYyW-WbTs
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09/2003 X5 3.0i 02/2003 X5 4.6is (non-runner) |
#6
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I had a similar thing end up being rust that got behind the dust shield. You prob have something inside the rotor/drum or between dust shield and rotor.
If you remove the rotor I bet you'll find a spot where the rust is evidently scraped away. I hear a double tap that might show up as two high spots on the rotor. Since it goes away faster it can also be on the outer edge of the rotor; as the rotor wears, sometimes the lip that grows on the end can touch parts of the caliper. Look for a scrape evidence.
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2011 E70 • N55 (me) 2012 E70 • N63 (wife) |
#7
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Thanks for the tips, appreciate it. At least the rotor is very worn, so there definitely is a significant lip. Replacing them is in my to-do-list for the summer. Anyway, I will try to find time to check the rotor and surroundings this weekend, at the latest next week. I'll report back what I found.
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09/2003 X5 3.0i 02/2003 X5 4.6is (non-runner) |
#8
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The video is very helpful. Now we know it's somewhere on the wheel end. Using the black tape on the wheel really helps timing the ticking sound.
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2003 BMW X5 3.0i -- MT5, 3.64s final gears, H&R lowering springs, K-Mac bushing kit 2007 BMW X3 3.0Si -- MT6 |
#9
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Check to see if where your e-brake hold downs go through the dust shield are still in good shape. That stamped "X" can rust out and your e brake shoes can move around. I had a very similar sound on my e34 and had to replace a wheel bearing just to get the dust shield/backing plate off. One other time I had a rock stuck between the rotor and backing plate and the noise went away when I pried the rock out.
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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed, |
#10
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An update to the situation, I decided to check the lug nuts of the wheel and all five of them were a bit loose. I was able to tighten all of them like 45-90 degrees. I don’t use a torque wrench for those, but have never had any issues with loose wheel nuts. I even double-checked all the wheels after changing to summer wheels and tires couple of weeks ago after having driven several hundred kilometers with them. Anyway, after the retightening, I have now driven over 300 km’s (190 miles) without the noise. Not really sure how the loose lug nuts would cause a sound like that but let’s hope that solved the issue. Or maybe there was something between the dust plate and rotor but it fell off by itself.
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09/2003 X5 3.0i 02/2003 X5 4.6is (non-runner) |
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