Clutch Judder K7003801

[garciapiano]

I've always experienced a significant clutch engagement judder with my TDI - both with the original clutch and after a by-the-book replacement with the stock Sachs "Quiet" K7003801 clutch. Brand new stock Sachs flywheel. Flywheel and pressure plate torqued to spec evenly. I have stock hydraulic mounts, save for the front mount which is the BFI stealth poly mount. All mounts are in good condition and installed correctly. But, the entire car vibrates when the clutch is slipping. I've just figured this is a characteristic of the mk3 platform and diesel engine. Maybe I'm not revving it up enough when clutching into 1st?

The judder is much less obvious when the engine is warmed up. I'm just curious if this is just a TDI thing... I haven't driven a gas clutch that judders as much as the TDI clutch.

 

[ToddA1]

Maybe it’s the poly mount? I don’t experience this on my cars.

-Todd

 

[garciapiano]

Maybe it’s the poly mount? I don’t experience this on my cars.

-Todd

Are you stock fuel and tuning? I am Malone Stage 2 with the DCL 1019s... so maybe it could be my slightly more aggressive tune. My guess is the IQ is a bit different on the cold start and that could be causing some of the roughness. Mount could definitely be part of it as well.

 

[ToddA1]

Two cars are stuck. One car has a Kerma tune with DLC1019.

-Todd

 

[Mongler98]

Did you replace or resurface the flywheel? A improperly bedded in or flywheel with hot spots will do this.

 

[garciapiano]

Did you replace or resurface the flywheel? A improperly bedded in or flywheel with hot spots will do this.

Whelp, sounds like I probably messed up my new flywheel. Not sure how I’d drive it differently since I am not someone who rides the clutch.

I’ll try a stock front mount and see if it helps any.

 

[Steve Addy]

Whelp, sounds like I probably messed up my new flywheel. Not sure how I’d drive it differently since I am not someone who rides the clutch.

I’ll try a stock front mount and see if it helps any.

I wouldn't write off the flywheel yet...

Steve

 

[Mongler98]

Take a look at the BFI mount. I'm assuming you used the replacment bolt that came with the kit?
I did. They sent the wrong one or something but the bolt was a little bit longer than it should have been. It caused a lot of shaking like you described.
Worth checking out.

 

[h.ubk]

I don't think this is a part of the MK3 platform. Mine doesn't do that.

h.ubk

 

[Mongler98]

I don't think this is a part of the MK3 platform. Mine doesn't do that.

h.ubk

OP's car is a 1997 Jetta TDI (1Z)
DEFINITELY an MK3

 

[garciapiano]

I got the OEM front mount and threw it on. Definitley a more isolated ride than the BFI front mount. With OEM mounts all around, the slight judder during clutch slip is certainly still there but the car is generally more tamed, so I like that. Not sure how long these mounts will hold up under Stage 2 driving, though. At this point I've pretty much given up on having that "transparent" gas-like clutch action.

 

[garciapiano]

The clutch judder is bad. So bad that I’m embarrassed to drive my girlfriend around in it. I’m going to guess that there are two things going on here:

- Runout or hotspots on the flywheel
- crank walk due to bad thrust bearings (I really hope not)

The exact same judder problem manifesting with two stock style clutches is a worrisome prospect. Either I suck at breaking in the clutch or there is something else engine-related going on. I am going to tear it apart this weekend and try again with a LuK A4-style DMF. I’ve always been a bit perturbed by the harshness of the AHU and I’m hoping the DMF A) survives my power upgrades and B) doesn’t suffer the same hotspot fate that the Sachs Quiet Clutch did. And hopefully drive a bit more smoothly.

 

[Marc Bourget]

Not mentioned but I'm assuming you're practicing a "dead throttle start"

Leave foot off throttle and careful with letting out the clutch. Minimizes if not eliminates the shudder. If I try to drive it like a gas engine, shudder gets worse.

 

[Jetta SS]

My car does this too. While cold. Once it's warmed up it stops. I'm still running the original clutch.