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Discussion Starter #1
As the title would suggest.

Replaced so far:

Three of four engine mounts

Both front wheel bearings

Gearbox oil replaced (some swarf but nothing unusual)

No vibrations through pedals or gear stick

Clutch and flywheel replaced circa 10k ago

Both driveshafts replaced (remanufactured and under warranty)

Driveshaft replacement had nearly fixed the issue (as it was much much worse) but under acceleration when exceeding 60mph a high frequency vibration starts (very similar to driving over corregations/course road surfaces/a "mild" version of the white line at the side of the motorway at speed).

Any ideas anyone?

I'm wondering if the replacement driveshafts are duff.

Tracking seems a little off (c. 2-5 degrees) and all wheels recently balanced.

No clicking on full lock (going forwards) either...

I'd love to get it sorted as with the amount of work I've done I'm starting to get a bit fed up with it.

Not looking at AutoTrader yet. But I'm getting tempted...

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Only under acceleration when above 60 mph? So no vibrations if you, for example, cruise at a constant 70 mph?

I'm just spitballing here, but could it be that at 60 mph, the suspension geometry changes enough to cause some worn component in there to vibrate under acceleration?
 

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Suggest checking the brakes and the wheel weights. Sometimes it can be the rears,


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Does it feel like it's a lateral shake of the front of the car, like the wheels want to shake off when you're putting some power on?

How long ago were the driveshafts done?
Mine were done about 2 years ago because of I think what you describe. I have the shakes again now, so I'm assuming it's spiders or shafts again. Maybe I just have too much torque with the map and its destroying driveshaft spiders for fun.
 
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Discussion Starter #7
I definitely destroyed my old driveshafts. And yes, I've had a remap that the rolling road indicated 480ft lbs torque.

The shafts are about a week old. There feels to be perhaps a millimetre of rotational play in the spider/cup assembly on the drivers side (if that makes sense).

Passenger side is tight seemingly.

Would that degree of play be enough to cause the issue or is that within tolerance?

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Discussion Starter #9
Destroy is perhaps a strong word. I certainly know that the joints ejected their grease, which caused the onset of failure. But I take your point.

I don't believe the diff is an issue but neither do I know if it's been checked.

I'll put it on the list....

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Discussion Starter #10
Destroy is perhaps a strong word. I certainly know that the joints ejected their grease, which caused the onset of failure. But I take your point.

I don't believe the diff is an issue but neither do I know if it's been checked.

I'll put it on the list....

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Thinking about it, this only presents under load. Plus I have no whine from the driveline at all.

Also, planting the throttle from low speeds gives no vibration that I can discern. It's only when I exceed circa 60 mph.

If it was the diff I'd be getting symptoms all the time, wouldn't I?

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I would expect more signs of damage if it was the diff, yes. That's why I still think some suspension component is possibly the issue - suspension geometry changes depending on speed, partly as a result of the airflow around the car, which might be why the issue is only showing up under very specific circumstances.

But I'm not expert on this. :paperbag:
 

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Is it a real vibration or a feeling of any vibration ???...
So if it is a real vibration the right question is what does vibrate exactly ???...
I would suggest one thing especially because your car one half rebuild with new parts.
There exist a plastic shield behind front wheel each side fixed with two bolts.
If bolts are loosen ( or lost even ) this shield play creates some nasty feeling that something serious happens. It happens exactly on acceleration. Check it.
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When my spiders and near side omocinetic joint needed replacing, it was very similar to having an unbalanced washing machine on full spin sitting on the axle- yes that violent a shake. I have the same again, so I'm hoping it's just the offside joint that needs doing now otherwise I've killed the spiders etc in 1.5 years.

If you go back to the early years of this 159 sub forum, there's plenty about driveshafts failing early on in the car's life and it's mainly with standard torque. Be nice to know how many people with remaps are having to replace driveshaft components way too regularly.
 

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Discussion Starter #15
Yep. That's exactly what I had. That's a very good way of describing it.

What I do know is that this vibration want there before, so I do wonder if something got damaged.

I'm seriously considering demapping, or at least getting the torque reduced once I work out what this problem is...

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Discussion Starter #16
Right, I'm under her today.

With the gearbox in neutral I have seen that there's rotational play in the drivers-side driveshaft. (On ramps so the wheel isn't moving).

Furthermore the play isn't fully transmitted through the cup/spider (i.e. There's slack).

My calcs tell me that I've got 0.6 mm of play (23 thousands or just under 1/32 as a guide).

I'm currently looking for a reference point, but wondered if anyone on here knows what the actual tolerance is supposed to be for the cup and spider?

Or, if this play is considered acceptable?



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Bio idea what is acceptable but I can roll my driveshaft back and forth and get a nice knocking in the spider area. I kind of assumed this was normal and would tighten up under load.
 

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did you find a solution for the problem? i also have the vibration. So far i changed a lot of parts with no success in resolving the problem. At Bosch service they said that it may be the right engine mount or something in the gearbox.
 

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Get it on a rolling road. That should help you look at the car and listen for the source whilst running the car up to the problem speeds
 

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I would look at the drive shafts. You'll feel it through the seat more than steering. The vibration will be worse under load so get a few people on board and accelerate uphill at about 60MPH. If the vibration stops as soon as you lift off the throttle then it is drive shafts.
 
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