Kupplungsrutschen beim PD TDI ist kein Problem der Kupplung! | Posts 32+

BM wrote:

... Not quite, it's only meant to have a supportive effect.

That kind of assistance, however, distorts the pedal feel. It makes it difficult to judge whether the pressure plate reacts in a reasonably linear way. That will definitely be prevented by the dead center spring ...

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What could be possible is that VW may not have perfectly calibrated the spring force of the Belleville washer in the pressure plate, so that a proper reversal of force may not occur there for very long (even with very little wear). (See a technical manual for automobiles or...).

That's possible, but it has nothing to do with the clutch slipping.
However, because of this stupid feeling, I let myself get distracted and ended up stalling the car, and I thought my clutch was broken.

Herr Antje wrote:

It could also be a reason for the wandering print point... I once had a leak, but it didn't cause a slipping clutch; instead, it resulted in a wandering engagement point.

It's kind of a maybe... Usually, if there's a leak, the pedal will eventually start to sink. I wouldn't completely deny it, though.

I'm more inclined to believe that the bleed hole wasn't always fully open, which meant that the warming system (and thus the expanding brake fluid) caused the clutch to disengage.

The following points were particularly noteworthy:
- The error always occurred after a specific distance (25 km) and under very specific ambient temperatures (between -2 and +2°C).
- Once the clutch was engaged, the slippage disappeared in 80% of the cases.
- In multi-core systems (i.e., under extremely high thermal stress), I never experienced any throttling issues.
- The more clutch slips I experienced, the lower the likelihood that the clutch would start to slip.

Unfortunately, the effect worsened progressively, and eventually, the clutch simply failed on its own.

Hi,

It is also said that the friction-optimized master cylinder replaces the existing part. The slave cylinder is not affected. In cold weather, the old sensor prevents the clutch from being fully disengaged due to excessive friction.

I suspect that these noticeable donors are more likely to make noise, which is a fairly common issue. When I casually mentioned the noise during the upcoming maintenance, I found that the coolant reservoir was quite damp when I picked up the vehicle, even though, according to the order, the coolant wasn't supposed to be changed. Well, and the creaking was also gone after that .

Hi everyone,

'Everything you're writing here is very interesting. I'd like to summarize briefly for myself. Initially, it was assumed that the receiver cylinder should be replaced with a part number 1J0 721 261 J. However, this only provided temporary relief. It was only after replacing the donor cylinder that the clutch stopped slipping.' Correct?

Okay, here's the translation:

Now, my question is: Which master cylinder do I need to order for my ASZ engine in my Octavia 1U5? And where can I find it at the lowest price?

What should I be aware of when making the switch? Are there any tricks or things one should pay particular attention to?

cu
smith2

Hi everyone,

I just did a quick search in WebCat for ZF Sachs.
Master cylinder VW part number: 1J1 721 388 E, Sachs part number: 6284 000 033, EAN: 4013872369980.

Is this the right one? Where can I get it for the cheapest price?
cu
smith2

smith2 wrote:

... Replacing the master cylinder alone didn't prevent the clutch from slipping. Correct?

No problems for over 2 weeks.

If the clutch is already slipping too much, then it's likely time to replace it.

Quote:

... What should I be aware of when making the switch? Are there any tricks or things one should pay particular attention to?

I hope you have peace and patience.
For the G4, that's an extremely difficult thing.
You need a sturdy ratchet with one long extension and two short extensions (or two long extensions). What for? Later more...

Okay, I can only talk about this in relation to the G4.
- Completely remove the trim pieces located below the steering wheel.
- Remove the retaining plate in front of the brake pedal and clutch pedal.
Okay, let's go outside for now.
- Completely remove the air filter housing and intake manifold.
- Between the brake booster and the longitudinal support, you can glimpse the back of the master cylinder (visibility is somewhat limited).
- Remove enough brake fluid from the reservoir so that no more fluid can escape from the bleed hose connected to the clutch.
- Disconnect the return hose from the donor cylinder.
- Disconnect the pressure line from the receiver cylinder (fortunately, it's only clipped on).

- Inside, remove the three screws on the injection molding wall using the very long extension, and completely remove the clutch pedal block along with the sensor cylinder.
Caution: Work carefully and do not damage anything!
- Carefully remove the master cylinder from the pedal assembly on the workbench, and reinstall the new one in the same way.
- Reinstall the pedal assembly and tighten the screws (including the mounting bracket).
- Reinstall the drain line and pressure line.
- Top up brake fluid and bleed the system.
- Reinstall the air filter housing and intake manifold.

- Test drive

- Make sure everything is okay, and reassemble the interior trim pieces.

Quote:

I just did a quick search in WebCat for ZF Sachs. Master cylinder, VW part number: 1J1 721 388 E, Sachs part number: 6284 000 033, EAN: 4013872369980. Is this the right one?

For me, it was part number 1J1 721 388 A.

Quote:

Where can you get it the cheapest?

It's not that expensive, even when bought from an authorized dealer.

WOW ,

Thank you, BERTIL, for the information. I will get the donor cylinder from my friendly supplier. The clutch rarely slips, but it still feels 'strange,' especially since I've never really driven with a load (like a caravan or trailer).

Sure, here is the translation of the text from German to English:

'cu smith2'

hello,
Old topic; new theory!
After replacing the master brake cylinder and performing the corresponding work on the brake lines and reservoir, I suddenly have at least 3 cm of free play in the clutch pedal before the clutch starts to disengage.
That's 2.5 cm more than before!
why is that?
My only explanation is that there is a constant, slight overpressure in the expansion tank.
However, that shouldn't be the case, as the brakes would then always be slightly engaged.
However, this is not the case if the master cylinder is not in the balanced position.

Is there another explanation for this phenomenon?

Hi Leo,

Overpressure in the expansion tank is impossible. There is a ventilation hole in the lid.

Are you sure that the clutch hydraulic system was bled after the renovation?

Roger wrote:

Overpressure in the expansion tank is impossible. There is a ventilation hole in the lid. Are you sure that after the renovation, the clutch hydraulics were also bled?

... because it had not been properly ventilated.
I don't think it's necessary if the clutch's bleed hose was only removed and reattached. It should bleed itself in that area.

Hi Leo,

Well, what is "normal" anyway...? Just give it a try; it's not really that much work, and it's definitely worth a shot. Although, theoretically, I would also see it the way you do.

Okay, let's shake off the dust and get an update going...


Clutch problems again (continued and solution to the drama).

In January, things started up again. The clutch was slipping again, albeit very slightly, but it was noticeable.

So, at the end of January 2007, I purchased a clutch from "Sachs Race Engineering" along with the matching pressure plate. This clutch, in the configuration I chose (pressure plate + solid clutch disc with organic friction material), is specified for 325 Nm of torque. That should be enough.
On Saturday, February 24, 2007, I installed the SRE clutch. I also replaced the release bearing. In addition, I noticed a leak on the right-side differential oil seal. It was also updated.
The first test drive immediately reminded me of the clutch from my rally car.
Initially, the pedal feel was a bit unusual due to the extremely small amount of play in the clutch. However, this became less noticeable quite quickly, and after about 150 kilometers, the clutch play returned to a largely normal level. However, it is clearly noticeable that the pressure plate has a higher clamping force than the standard part.
It is not advisable to release the clutch quickly as usual. The clutch will engage abruptly, and the car will immediately lurch forward. The stresses on the powertrain are then quite significant.
It takes some practice to get used to the unfamiliar pedal positions and forces, and it's important to pay attention during gear changes, as the clutch engages very quickly. "kangaroo diesels" (engine stalling) were almost unavoidable in the first few days.


Here are some surprising side effects I've noticed in my car after the clutch replacement:

1. - The clutch can now also handle chip tuning.
2. - The loud noise that occurred when shifting quickly from fourth to fifth gear has disappeared and cannot be reproduced.
3. - The switching forces are significantly lower.
4. - The car is running much more smoothly now.

1. That should be logical. The clutch is designed for that purpose.

Here's the translation:

Regarding point 2: This fact surprises me somewhat. I've driven various TDI models, and almost all of them had this problem. Until now, I assumed it was a general transmission issue related to overly rapid gear changes. However, it seems that the clutches in these models aren't disengaging quickly enough. The sports clutches are designed for quick disengagement, despite their significantly smaller footprint.

Regarding point 3, I can't explain it at the moment. It's likely that this is also related to the better/faster engagement of the clutch (see point 2).

4. The left engine mount and the torque strut (at the rear) were removed and have now been reinstalled without any stress or strain. Therefore, a significant reduction in noise transmission from the powertrain is already possible.

After everything that happened, it seems to me that the clutch was intentionally designed as a "weak point" in the system. Engines that perform slightly better than their specifications and exceed their paper performance figures then experience problems with the clutch. Chip tuning is often not possible at all, or only possible with limitations.
With the standard clutch, after shifting gears, it was rarely possible to avoid a jolt in the drivetrain when re-engaging. Often, I had the impression that the clutch continued to slip slightly after engaging. With the sport clutch, things are very different. Here, there is a risk to the drivetrain. Therefore, anyone who chooses the combination with the sport clutch should make their gear changes much more passive and gentle. Otherwise, the next damage (to the transmission or drive shaft) is practically guaranteed.



Here are a few notes for people who have never driven with a sports clutch before:
The forces applied to the pedal are significantly higher! This is due to the springs used in the pressure plate. In "stop and go" driving, you should already have well-trained legs. Holding the clutch in the disengaged position for extended periods requires significantly more strength and endurance in the foot. The clutch engagement travel and the area where the clutch slips are much smaller. Therefore, some practice is also needed here to avoid unnecessarily stressing the drivetrain. It's best to get used to using the idle function right away.
With the version using sintered linings, these characteristics are further amplified. The "grinding area" becomes significantly smaller in this case. More accurately, it's hardly present anymore.

Quote:

2. - The loud noise when shifting quickly from fourth to fifth gear has disappeared and cannot be reproduced. 3. - The switching forces are significantly lower.

In cases 2 and 3, the clutch diaphragm spring could also be the culprit (perhaps worn or too weak), preventing it from fully disengaging the clutch during release, or the now stronger spring may be translating the movements more directly without giving way internally.
It would also be interesting to know if there is a so-called Belleville washer between the friction material of the new clutch disc, which slightly expands the friction material when the clutch is disengaged.

May I ask how much the SRE training cost you?
I had also considered that at the time.
For me, it was around 500 euros back then, or something like that.

LG
Maxx.

BM wrote:

In cases 2 and 3, the clutch diaphragm spring could also be the culprit (possibly worn or too weak), preventing it from fully disengaging the clutch during the release process.

"With three clutches? Then I would have had the defect three times with different parts..." Almost impossible.
In each case, the complete unit (clutch, pressure plate, and dual-mass flywheel) was replaced.
I left the last dual-mass flywheel (DMF) in place, even though I'm using the SRE clutch.

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...or the now stronger spring translates the movements more directly, without giving way.

That's definitely true.

Quote:

It would also be interesting to know if there is a so-called Belleville washer between the friction material of the new clutch disc, which slightly expands the friction material when the clutch is disengaged?

No. The SRE is completely rigid. There are no flexible elements in the panel. However, the printing plate is completely different.

Quote:

May I ask how much the SRE training cost you?

Pressure plate and clutch disc: approximately 600 euros (I got a small discount).

Quote:

With three clutches? Then I would have had the defect three times with different parts... Almost impossible.

That's why I also said "......or too weak".

BM wrote:

... Therefore, I also meant "......or too weak".

I already understood that.
Since I also observed that, I suspected the hydraulics. That actually improved the situation for a while. But either my hydraulics are tired again, or the pressure plate has already worn out completely.
I would confidently say: Undersizing .