vibrations
10-15-2014, 12:20 AM
#1
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vibrations
I get fairly strong vibration from the rear at certains speeds (around 70-75km/h) and mostly under load (full thottle). It never feels as smooth as it should be though. I've checked and replaced all the usual stuff but a bit stuck now what it could be. The car has done around 120.000km's now and is a MY00 AP1.
Up to about 6 months ago it was absolutely fine, no vibrations whatsoever (was running on eibach springs, no driveshaft spacers). Shortly after that I bought some new Bilstein coilovers and had them installed and had the alignment setup after that. It sits a bit lower than before, but not nearly at the end of the threads. The car drove fantastic after that, a bit harder but also a more damped feel. Was very smooth on good road surfaces at all speeds.
A month or 2 later I noticed some slight vibrations at motorway speeds (120-130km/h) that came and went. I could also feel a very slight vibration at around 75km/h under load. I had the wheels balanced to make sure that wasn't causing it, but made no difference. I assumed this was a case of pitted CV joints, so ordered some driveshaft spacers. Had them installed right away, but made no difference. Then I decided to swap over the left and right CV joint cups, but also made no difference.
The problem was only slightly noticable and drove fine otherwise, so took the car on an already planned holiday to the Swiss alps. On the way there it developed another problem, it made a noise from the right rear wheel and every wheel revolution. Had that checked out at a local garage and turned out to be a wheel bearing. I wasn't possible at the time to have it changed, so decided to drive on and keep monitoring it. Along the way the noise didn't get much worse, but vibrations under load get a lot worse (which didn't make it a fun drive home!). I made it home and had the wheel bearing and the hub changed (was damaged as well), thinking that would be the end of it. But unfortunately not...
The noises have gone, but the vibrations are still partly there (although not nearly as bad). I'm a bit at a loss now what it could be! Drivehaft related? Differential? Prop shaft? Would love to hear an opinion from you guys.
There's one much thing though which might be unrelated, but you never know. In my opinion there's quite a bit of drivetrain slack when coming on/off throttle. Not noticable when pressing on, but around town it can sometimes be annoying. There's also a slight bearing like 'woosh' noise when just coming on or off throttle, don't hear anything when under any kind of load. Is not speed or revs related either and has done this for a very long time already.
Up to about 6 months ago it was absolutely fine, no vibrations whatsoever (was running on eibach springs, no driveshaft spacers). Shortly after that I bought some new Bilstein coilovers and had them installed and had the alignment setup after that. It sits a bit lower than before, but not nearly at the end of the threads. The car drove fantastic after that, a bit harder but also a more damped feel. Was very smooth on good road surfaces at all speeds.
A month or 2 later I noticed some slight vibrations at motorway speeds (120-130km/h) that came and went. I could also feel a very slight vibration at around 75km/h under load. I had the wheels balanced to make sure that wasn't causing it, but made no difference. I assumed this was a case of pitted CV joints, so ordered some driveshaft spacers. Had them installed right away, but made no difference. Then I decided to swap over the left and right CV joint cups, but also made no difference.
The problem was only slightly noticable and drove fine otherwise, so took the car on an already planned holiday to the Swiss alps. On the way there it developed another problem, it made a noise from the right rear wheel and every wheel revolution. Had that checked out at a local garage and turned out to be a wheel bearing. I wasn't possible at the time to have it changed, so decided to drive on and keep monitoring it. Along the way the noise didn't get much worse, but vibrations under load get a lot worse (which didn't make it a fun drive home!). I made it home and had the wheel bearing and the hub changed (was damaged as well), thinking that would be the end of it. But unfortunately not...
The noises have gone, but the vibrations are still partly there (although not nearly as bad). I'm a bit at a loss now what it could be! Drivehaft related? Differential? Prop shaft? Would love to hear an opinion from you guys.
There's one much thing though which might be unrelated, but you never know. In my opinion there's quite a bit of drivetrain slack when coming on/off throttle. Not noticable when pressing on, but around town it can sometimes be annoying. There's also a slight bearing like 'woosh' noise when just coming on or off throttle, don't hear anything when under any kind of load. Is not speed or revs related either and has done this for a very long time already.
10-16-2014, 06:18 AM
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Anyone has an idea? My garage thinks there's an excessive anout of play in the ingoing side of the differential (where the prop shaft meets the diff). I can see how this would cause my drivetrain slack, but not how that would cause the vibration issues.
10-16-2014, 12:58 PM
#3
2 things spring to mind:
- the wheel bearing on the other side
- the diff input flange nut loose
Did the shop follow the Billman procedure for torquing the rear hub nut? Was the the other side also torqued? Since that is basically free if you diy, I would start with that.
Next I would check the nut on the diff input flange. Need to remove driveshaft from diff, then its right there (mark where the driveshaft mates to diff flange prior to disassembly!) Another member on here at an odd vibration and went nuts trying everything, then eventually found it was the flange nut. Just retorqued, problem solved. This can also be diy, just a little more work as you need to remove driveshaft.
It might be difficult to diagnose if its wheel bearing on other side. If you can get it on a lift, and run it in gear, can use a mechanics stethescope to listen to bearing .
- the wheel bearing on the other side
- the diff input flange nut loose
Did the shop follow the Billman procedure for torquing the rear hub nut? Was the the other side also torqued? Since that is basically free if you diy, I would start with that.
Next I would check the nut on the diff input flange. Need to remove driveshaft from diff, then its right there (mark where the driveshaft mates to diff flange prior to disassembly!) Another member on here at an odd vibration and went nuts trying everything, then eventually found it was the flange nut. Just retorqued, problem solved. This can also be diy, just a little more work as you need to remove driveshaft.
It might be difficult to diagnose if its wheel bearing on other side. If you can get it on a lift, and run it in gear, can use a mechanics stethescope to listen to bearing .
10-16-2014, 07:31 PM
#4
Don't even need to remove the drive shaft, just the tail end of it(make sure you mark it so you know how to put it back), torque the flange nut(aka lock nut) until it takes between 7 to 12 inch pounds to rotate the flange 
the manual states a torque range anywhere between 94-210 ft lbs for the flange nut. Measure the force needed to turn the flange using a torque wrench with the bendy rod and rotate the flange with it(with a socket attached to the nut obviously). To tighten the lock nut, you have to keep the flange from turning, you can use the parking brake, or pony up some serious dough for that special tool with the bolt holes. I use the parking brake.
To recap, mark with white-out, then loosen tail end of drive shaft, use dial torque wrench to measure turning force of flange by turning nut, if under spec, tighten lock nut by using parking brake, and tighten a little at a time. Remove parking brake and see if flange turning torque is to specs. If it is, and the lock nut is tightened within range, bolt the drive shaft back up making sure to line up the mark you made, dab a bit of lock-tite on the prop shaft bolts, and torque to 24 ft lbs.
the manual states a torque range anywhere between 94-210 ft lbs for the flange nut. Measure the force needed to turn the flange using a torque wrench with the bendy rod and rotate the flange with it(with a socket attached to the nut obviously). To tighten the lock nut, you have to keep the flange from turning, you can use the parking brake, or pony up some serious dough for that special tool with the bolt holes. I use the parking brake.To recap, mark with white-out, then loosen tail end of drive shaft, use dial torque wrench to measure turning force of flange by turning nut, if under spec, tighten lock nut by using parking brake, and tighten a little at a time. Remove parking brake and see if flange turning torque is to specs. If it is, and the lock nut is tightened within range, bolt the drive shaft back up making sure to line up the mark you made, dab a bit of lock-tite on the prop shaft bolts, and torque to 24 ft lbs.
10-16-2014, 11:52 PM
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Thanks guys, appreciate the idea's! I've had a chat with my mechanic and it seems I must have misunderstood him. There is no excessive play in the prop shaft or diff input, but in the driveshafts. Both driveshafts (passenger and driver side) have play in them and can be moved by hand. I'm not sure now much is considered normal, but according to him it shouldn't be like this. There is a ring that can be tightened, but you'd have to open up the diff for that. Not sure if changing the diff would in fact be easier.
Perhaps a picture would help
If I'm correct you guys are referring to the nut circled in red. Might be wise to have a look at, but is probably not the cause. My mechanic is referring to the blue circled ring, which is used to tighten up the bearing/shaft?
Perhaps a picture would help
If I'm correct you guys are referring to the nut circled in red. Might be wise to have a look at, but is probably not the cause. My mechanic is referring to the blue circled ring, which is used to tighten up the bearing/shaft?
10-17-2014, 02:14 AM
#6
You're allowed a little play shoving the axles in and out of the diff, there should be no lateral play, also if the axle shaft isn't lubed at the splines past the axle nut you'll get an occasional clunk going from forward gears to reverse.
10-17-2014, 02:54 AM
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The axles do have some lateral play in the diff, so my mechanic may be right. However it's probably easier to replace the diff for a used one then opening it. I'm still not entirely convinced this causes the vibration tough, but I can definately see how this would affect the slack in the drivetrain.
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10-17-2014, 08:09 AM
#8
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try the easy/obvious thing first, the wheel balancing. check the prob shaft balance. diff flange nut torque. maybe the driveshaft outboard splines are worn. engine/tranny/diff mounts?
good luck.
good luck.
10-17-2014, 11:05 AM
#9
The axles do have some lateral play in the diff, so my mechanic may be right. However it's probably easier to replace the diff for a used one then opening it. I'm still not entirely convinced this causes the vibration tough, but I can definately see how this would affect the slack in the drivetrain.
10-20-2014, 02:27 AM
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Originally Posted by Jurgen79' timestamp='1413543280' post='23372792
The axles do have some lateral play in the diff, so my mechanic may be right. However it's probably easier to replace the diff for a used one then opening it. I'm still not entirely convinced this causes the vibration tough, but I can definately see how this would affect the slack in the drivetrain.