Clutch Replacement: Unexpected Issues & Solutions

Hello fellow DIY enthusiasts,

Here's a short account of my clutch replacement experience.


Okay, let me start by saying a few things:
The replacement of the entire clutch (including the dual-mass flywheel) was a complete success.
In addition to the sliding issue, the following other errors have been resolved:
- The slight idle vibrations that I've been experiencing for about 20,000 km are gone (although they weren't that bad).
- The transmission, which has been making noise for 65,000 km, can now finally be shifted smoothly and quietly, without force or noise.
- The clutch engagement is now noticeably smoother and lighter (it engages earlier - disengages later - and the possible clutch travel is significantly longer).
- The bouncing when starting is now gone.
- The speed-dependent whistling noise during the warm-up phase is now gone (it wasn't related to the clutch).


But let's go step by step.
"On Friday, I started by carefully removing all the coverings (it's surprising what's hidden these days) and the battery along with its casing. I also had to remove the air filter housing. This isn't strictly necessary, but it provides a better view. I removed the starter motor and disconnected all the electrical connections to the transmission. After suspending the engine from a fender brace, I removed the complete engine mount on the left side and the torque support under the transmission. Then, I removed the bracket for the cable linkage and the clutch slave cylinder, hanging them above, which freed the transmission. However, I then saw that the hydraulic line for the power steering, which runs around the transmission, would be a problem. Upon closer inspection, it turned out that this line could be gently pushed over the transmission and therefore remain connected. To create more space, I then decided to remove the left drive shaft."
Now I pulled the gearbox out sideways from the clutch. Since I was alone, I couldn't easily lift the gearbox out, so I decided to "park" it on a wooden block on my pit cover underneath the car. This meant I only had 30cm of space between the gearbox and the clutch, but that was more than enough.

Then the clutch disc came to light... and it turned out to be an AT part.
So, the vehicle in front of me must have already had a new clutch installed. That makes the offer of a 40% discount on VW parts seem even more ridiculous to me.
The wear pattern on the old clutch was actually perfectly fine, except that it was completely glazed. No significant signs of wear were visible on the pressure plate or the dual-mass flywheel.
Despite these good prospects, I decided to replace the ZMS anyway. The "new" clutch (with 11800 km on it) had already started to wear down, and it's always better not to swap parts between different components.
Everything was reassembled, and after 8 hours of pure assembly time (completely alone), the job was done.

While assembling, I unfortunately snagged the vacuum hose on the vacuum reservoir. As a result, the connection broke off. When I then removed the vacuum reservoir, I noticed a 2 cm crack on the back. The other engine still had a working vacuum reservoir, which I then installed. That was probably the source of the whistling noise.
By the way, this vacuum reservoir is mounted on a 2x10cm metal plate, and the entire unit weighs just under 250 grams, but it's still secured with an M8 Allen screw. I wonder what else VW intended to attach to it.

The ZMS clutch unit can be completely assembled and disassembled using a long 12-tooth spline shaft. I could have even avoided disassembling the clutch altogether.


Special tools required:
9mm 12-point nut (pressure plate on the clutch disc).
16mm socket (no, VW no longer uses 17mm sockets).
18mm nut (no, VW no longer uses 19mm sizes).
30mm 12-point nut (axle nut, driveshaft).
8-tooth spline (drive shaft, inner side).
12-tooth spline (ZMS to crankshaft).
Fender crossmember.
Engine/transmission hoist.
Centering pin (I estimated the diameter using visual approximation and multiplied by Pi).
Locking mechanism for flywheel.



Conclusion:
Once all the coverings have been removed, changing the gearbox is a piece of cake.
You can safely ignore the standard tools (17mm and 19mm wrenches).
A TDI transmission is... heavy.
I removed quite a few parts that weren't actually necessary, but it ended up making the job much easier in the end.
The clutch was junk from the very beginning!
If I ever catch the architect who convinced me to build a basement during the house construction... I'm going to have a drink with him.

Bertil wrote:

In addition to the sliding issue, the following other errors have been resolved: - The slight idle vibrations that I've been experiencing for about 20,000 km are gone (although they weren't that bad). - The transmission, which has been making noise for 65,000 km, can now finally be shifted smoothly and quietly, without force or noise. - The clutch engagement is now noticeably smoother and easier (it engages earlier - disengages later - and the possible clutch travel is significantly longer). - The bouncing when starting is now gone. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. The wear pattern of the old clutch was actually completely fine, except that it was completely glazed. No significant signs of wear were visible on the pressure plate or the dual-mass flywheel.

Hi Bertil,

Can you attribute the frosting to any specific operating conditions that you are aware of, but that others might be able to avoid?

Were you able to identify anything that might explain why shifting was so difficult before?

Otherwise: It's great that everything worked out so well .

Hi Ulf,

ulf wrote:

.... Can you attribute the frosting to any specific operating conditions that you are aware of, but that others might be able to avoid?

Unfortunately, not.
Bremsscheiben oder -beläge, die Anzeichen von Verglasung aufweisen, sind grundsätzlich immer das Ergebnis von starker Überhitzung und schlechter Wärmeableitung. Diese Überhitzung sollte jedoch auf der Druckplatte oder der doppelten Massenschwungscheibe (ZMS) sichtbar sein.
I think the printing plate was the real culprit.
The clutch would always disengage prematurely, even when the foot only touched the pedal (meaning, far too early). Some drivers don't take their foot off the pedal at all (I don't...). When these two factors combine, the clutch is ruined in a very short time. Because glazing prevents the friction linings from self-cleaning (or makes it increasingly difficult), the friction factor also decreases. The clutch starts to slip.

Quote:

Were you able to identify anything that might explain why shifting was so difficult before?

Again, no. Since I haven't adjusted anything in the circuit, the clutch was probably the culprit. However, it could also have been the dual-mass flywheel. The entire shifting process is now much smoother. Before, I felt like I was driving with a stiff, unsprung clutch.
I still don't understand the reason why they moved the torsion spring from the clutch disc to the flywheel.

Hi Bertil!
Did you also replace the needle bearing and the crankshaft oil seal?
This weekend, I also started replacing the clutch at a friend's place. Unfortunately, we didn't have a replacement for the faulty needle bearing.

wolfi_b wrote:

Did you also replace the needle bearing and the crankshaft oil seal?

No.
The rear axle bearing was in excellent condition (which it should be at 80,000 km), and the seal was perfectly dry. Therefore, I didn't see any reason to replace those parts.

I didn't mean the release bearing, but the needle bearing that sits in the crankshaft and receives the end of the input shaft of the gearbox. Or is it different with dual-mass flywheels?

So far, I haven't experienced any needle bearings failing.

wolfi_b wrote:

I didn't mean the release bearing, but the needle bearing that sits in the crankshaft and receives the end of the gearbox input shaft. Or is it different with dual-mass flywheels?

In which week?
There was no storage space available for me.

I didn't mean the release bearing, but the needle bearing that sits in the crankshaft and receives the end of the transmission input shaft. Or is it different with dual-mass flywheels?

In which week?
There was no storage space for me there.

Huh? What is that? Normally, every engine with a manual transmission has a needle bearing in the crankshaft. Automatic transmissions don't have that. But I think you were just wearing the wrong glasses .

lappen wrote:

So far, I haven't experienced any needle bearings that were defective.......

I'm not particularly surprised, considering it has over 250,000 km.

I can take a photo for you .

In some cases, only half of the rolling elements remained. This acted like a partially disengaged clutch, making it difficult to engage the gears in some instances. No noises were heard.

'A photo would be interesting. We've already replaced several couplings with higher mileage, and in those cases, the needle bearing was fine. How do you remove the bearing from the crankshaft?'

I hope Bertil doesn't mind us picking apart his thread a little, but it fits the theme.

That remains to be seen. Either with some kind of tool, or I got the tip to fill the hole with grease, insert a bolt with a diameter that's not too small, and tap it in with a hammer. The pressure should push the bearing out .
This afternoon, we'll see if it works.

Yes! I hadn't thought of that... Sorry, Bertil, if it bothers you, just delete it!


Hmmmm, a hook? I don't know. I don't think it would work well. Grease? Awesome!! But if it works, why not. I've already thought about making something similar to a wall anchor, and then somehow thickening it behind the needle bearing. But so far, it hasn't been necessary.

wolfi_b wrote:

I hope Bertil doesn't mind that we're going to pick apart his thread a little bit, but it fits the topic.

...

lappen wrote:

Yes!! I hadn't thought of that.... Sorry Bertil, if it bothers you, just delete it!

It's okay.
It's about sharing experiences right now.
Even though it might sound trivial, it's often the smaller things that really cause delays.

On the G4, for example, there's a small metal plate located behind the right drive shaft, which is secured with a 10mm screw. This plate needs to be removed, for example, to allow the drive shaft flange to clear the flywheel.

Tonight, I'll talk about needle bearings. I'll check a sample engine to see how they work (it would be great if there's one available).

Hi,

Which car was it?
At least the G3 doesn't have a needle bearing.

Greetings,
dieter

Audi 80 1Z.

Quote:

At least the G3 doesn't have a needle bearing.

I also couldn't find any in the AKTE system for the G3.