Unwucht und große Ratlosigkeit | Posts 16+

Okay, so...

I'm making progress. The tires are still fine after being balanced, the brakes have been completely cleaned and are working properly...

What I've noticed is that the right driveshaft (the one with the new joint) can be easily pulled outwards and pushed inwards, while the left one is completely stuck. It won't move in or out at all... is this normal?

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The right drive shaft (the one with the new joint) can be easily pulled outwards and pushed inwards.

The condition is not normal. Normally, the outer joint does not allow for any length adjustment unless it is defective or the joint is not properly secured (e.g., the wire locking mechanism is missing or not engaged).

Fold back the cuff and check it before things get thrown at your head.

"But so far, it's always been the case that the drive shafts have some play? I was also told this by Seat today, because that's what allows for length compensation during suspension travel..."

I have an appointment this week; the workshop foreman will take a look at it. Currently, there's a wave available from eblubb for €60, and if necessary, I'll buy it.

SEAT said that the inner joint might be faulty.

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but so far, it has always been the case that the drive shafts have some play? I was also told this by Seat today, because it is said to provide length compensation during suspension travel...

You're talking about verschandeln passing and not about regular gameplay.

Die Welle selbst lässt sich im eingebauten Zustand nicht schieben, wenn doch ist was defekt oder lose. Einzig und allein ist das innere Gelenk schiebbar, das äussere nicht. WOkay, also auch.
Under normal playing conditions, the wave can be moved back and forth by about 1 to 2 millimeters; no more than that.
Another possibility, although less common, is that the left propeller blade is under tension because the engine isn't perfectly aligned in the center.

"Strange, strange... I was told that a slight play of about 1cm on the wave, on the passenger side, would be okay... so I mean not rotating the wave (it's very tight there), but rather pulling the wave away from the transmission and then towards the transmission."

If it were the bearing, that would be fine, as the outer joint has been replaced recently and should still be under warranty. However, it's been a while since the replacement, and the imbalance only became a problem recently.

The left driveshaft's constant velocity joint makes a very slight clicking sound when I turn it, and it absolutely won't pull or compress.

I will take the car back to the Seat dealership on Monday for another inspection, as they have already been working on the imbalance issue for some time.

Okay, so...

Here's the summary of the results:

According to SEAT, the drive shafts are adjustable, meaning they can be moved towards the transmission/wheel bearing to compensate for any play or slack.

The left drive shaft is completely seized in this direction, but has some play when rotating, meaning it's worn out.

Essentially, the left wave is flat, and this is causing the imbalance and preventing the steering wheel from returning to the center position, despite a correctly measured front axle.

I'm now going to either buy a refurbished or used shaft and have it installed, and then hope that everything will be better.

Regards,
George.

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Drive shafts are adjustable, meaning they can be moved towards the transmission/wheel bearing to compensate for any play, according to SEAT.

This statement is not entirely correct.
Again, the wave itself is not adjustable; only the internal joint connecting to the driveshaft is. There's just a little bit of play in the outer joint (which isn't an adjustable joint), nothing more. But it doesn't matter anyway, since it's not my car.

Let's hope you don't break your neck while driving that thing.

Hi.
How else can the suspension travel of the left-hand arm be compensated for, other than by shifting the arm outwards or inwards within the joint?
If it were completely solid, would that shift the gears or something?
If the outer part of the wave is fixed, it cannot be shifted inwards, but there must be space for it in the inner joint. However, you only notice this when the part is removed or detached from the outside.

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Hi. How else can the vertical travel of the left wave be compensated for, other than by shifting the wave outwards or inwards into the joint? If it were completely solid, would that shift the gears or something? If the outer part of the wave is fixed, it cannot be shifted inwards, but there must be space for it in the inner joint. However, you only notice this when the part is removed or detached from the outside.

Look at this: http://www.t4-wiki.de/wiki/Gelenkwelle (I suspect the error is in point 9).

The outer joint is rigid in the axial direction. The complete displacement (axial compensation) occurs in the inner joint.

If the shaft can be moved axially in place using a wrench, there's likely a problem because the outer joint is supposed to be rigid. (The exception is rear-wheel drive vehicles from Mercedes. These have two sliding joints.)

Yes, I also see that the shaft piece, which is rigidly connected to the wheel and outer joint, shifts inwards towards the inner joint, but only during suspension compression. Otherwise, it doesn't shift outwards or only shifts minimally.
Expanding view.

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Due to this additional function, this joint is also called a sliding joint. It only allows for small angles of bending, but it enables an axial displacement of the shaft by approximately 5 cm.

You're right, that's what it says. So, the inner joint is probably worn out... unfortunately, the outer one too; it definitely has a lot of play in its rotation and makes a "clicking" sound when starting.

Tomorrow I'll know for sure. The suspension will be replaced tomorrow. I just ordered a new outer and inner tie rod end; the purchase price of €115 is actually reasonable, considering that those parts cost almost three times as much from SEAT.

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That's what it says, you're right. So the inner joint is probably flattened...

No, not necessarily. You can only check this by removing it from the transmission, because a properly secured, axially rigid outer joint prevents this inspection.

Again, and this is the last time: If the INNER joint of the driveshaft allows axial movement, you have a serious problem there. I suspect that either the retaining ring is not properly engaged, or the spacer rings are missing. This causes the shaft to shift axially within the splines, and in the worst-case scenario, it could become disengaged. And then it becomes very dangerous if you're unlucky.Therefore, please double-check!

Hello BM,

I completely agree with you. However, the part was inspected by a SEAT specialist and deemed "okay." I'll bring it up again today. I might have also explained it poorly; it doesn't necessarily have play in the outer joint, but the shaft can shift slightly, and it's possible that only the inner joint is shifting during that movement.

I will definitely follow up again to ensure that this is checked thoroughly and that the rubber bellows are removed (on the right side).

My surgery is scheduled for 10 AM, and I'll know more after that.



Edit: Update regarding the workshop appointment.

Okay, so you were right, yesterday was a mistake. On the left (fixed) side, we only replaced the inner joint because it was completely stuck, and the imbalance has noticeably improved. I'll replace the outer joint on the other (loose) side in the next few days; it seems like the retaining ring came out.

Okay,

"Now both sides are working again. It wasn't the retaining ring, but the plastic spacer behind the outer joint... it was no longer there, even though the joint had only been installed relatively recently; either it was forgotten during installation back then, or it disintegrated."

Now both waves are perfectly stable, and the imbalance is gone.

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It wasn't the retaining ring, but the plastic spacer behind the outer joint... it was no longer found, even though the joint had only been installed relatively recently; either it was forgotten during installation back then, or it has disintegrated.

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I suspect that the retaining ring is not properly engaged, and/or that the spacer rings are missing.

I'm saying it , I would bet €100 that it was forgotten... it has happened to me before too .
It's a shame about the money that was wasted unnecessarily.

Well...

"Money was essentially wasted on expanding the left A-arm, and even then, only to 50% because the inner joint was completely seized, which I replaced at the same time. That's why I prefer to replace everything completely because I plan to drive this car until it dies, and I'd rather invest properly and do everything right so I don't get stranded somewhere and have to have the car towed."

The starter ring either disintegrated into powder or – as you and I suspect – simply wasn't there in the first place.

My theory about it is:

While removing the gasket, it was accidentally pulled down with it and ended up getting stuck inside the grease reservoir. This ring definitely wasn't included in the retrofit kit; I installed it myself... so it was simply overlooked.


That's why it's really great that this forum exists, because I wouldn't have been sure myself whether a wave needs to be fixed or free-moving.

Therefore, once again: THANK YOU, especially to you and everyone else who helped.

My entire front axle (and my nerves) will thank me for the next tens of thousands of kilometers.


For my own curiosity and to get a complete picture, I'd like to know if someone can explain how a loose drive shaft causes temporary imbalance... I can only imagine that the shaft is constantly moving back and forth towards the transmission/wheel hub, which introduces instability into the chassis... is that correct?


Greetings.
George.