One of the family had questioned the clutch operation, so I went for a fairly long trip in the Greenline today to get it warmed up, set the parameters for a regen etc. 

 

After a few miles I noticed a scuffing rumbling that I first thought seemed to be at road speed, but then in town I noticed the pedal getting stiffer, and a clutch slip and a rattle from the engine bay in that last part of the pedal travel just as before its fully released.

 

Clutch gives no sign of slipping at full throttle in 2nd, but roll on in 5th does seem a bit sluggish but I put that down to it being a 1.6tdi. 

 

My diagnosis = DMF, or clutch release.

 

Any thoughts would be helpful (I know I'm going to need a 2nd job to pay for repairs)

 

 

The clutch will of course slip at the bottom of the pedal travel, it should not do so when your foot is off the pedal, if its worn then it will manifect in top gear first.

 

You should be able to feel it or see it on the rev counter, another indication would be the gear indicator on the maxidot changing to a lower ratio than the one you have actually selected.

 

Editted, I misread your posting, you said just before release.

 

There is a plastic bleed block called a peak torque limiter because it actually slows the release of the clutch and resumption of turbo boost, its intended to protect the drive train from traffic light grand prix starts,  the tiny orifice could have become blocked by a particle which would explain all of your symptoms, its a cheap and easy repair to have done before you accept the labour charge of replacing the DMF and clutch.

Edited 27 February, 20215 yr by J.R.

Greenline does not have a DMF.

40 minutes ago, J.R. said:

There is a plastic bleed block called a peak torque limiter because it actually slows the release of the clutch and resumption of turbo boost, its intended to protect the drive train from traffic light grand prix starts,  the tiny orifice could have become blocked by a particle which would explain all of your symptoms, its a cheap and easy repair to have done before you accept the labour charge of replacing the DMF and clutch.

 

Now that is interesting as I've just been out checking the brake reservoir levels thinking the mechanism rather than the clutch itself is the issue ... I've never heard of this part can you give me an idea where this item is situated on a 1.6tdi motor please? 

4 hours ago, Urrell said:

Greenline does not have a DMF.

 

I did not know that !

 

17 minutes ago, b1ackb1rd said:

I've never heard of this part can you give me an idea where this item is situated on a 1.6tdi motor please?

What part are you asking about if the clutch slave cylinder it's in the bellhousing.

assuming the 1.6 is no different to the 2.0 Tdi then its the connection between the flexible pipe leading to the clutch housing and the plastic tube of the concentric release bearing. Its adjacent to the gear linkage under the air filter housing and has a white knurled knob and vertical bleed nipple.

 

If you remove the U duct between the inlet water snorkel (unclip the lid first) and the air filter housing you will probably see it, if not then remove the filter housing and all will be revealed.

 

I have spent far too much time in that area over the last few weeks for similar as yet undiagnosed and probably unrelated problems, in the course of which I have learned all about its operation and the IMO dubious reasons for its existence.

 

Basically you can declutch as fast as you can push the pedal to the floor the shuttle valve offers no resistance but when engaging the clutch it will only return at its own speed even if you sidestep the clutch, there is a tiny metered hole allowing the fluid to return and the master cylinder only has one seal and does not draw fresh fluid from a partial vacuum on the upstroke like a traditional one.

 

I drilled mine out thinking that it was causing my problems and found that the throttle pick up between gearchanges was much faster with virtually no delay for the turbo spooling up, it was not the problem so I have refitted a standard unmodified one to avoid other possible problems.

 

At the very least you should pressure bleed your system from this valve, if the fluid comes out black then you will have a failing master cylinder like I did, any of these particles could restrict the metered hole, indeed there is a high powered magnet on the end of the master cylinder piston which was covered in rubber like remains of my seal which must have had metallic composants in the mix.

 

The clutch master cylinder on RHD models gets very hot from the DPF.

Edited 27 February, 20215 yr by J.R.

40 minutes ago, J.R. said:

assuming the 1.6 is no different to the 2.0 Tdi then its the connection between the flexible pipe leading to the clutch housing and the plastic tube of the concentric release bearing. Its adjacent to the gear linkage under the air filter housing and has a white knurled knob and vertical bleed nipple.

 

If you remove the U duct between the inlet water snorkel (unclip the lid first) and the air filter housing you will probably see it, if not then remove the filter housing and all will be revealed.

 

I have spent far too much time in that area over the last few weeks for similar as yet undiagnosed and probably unrelated problems, in the course of which I have learned all about its operation and the IMO dubious reasons for its existence.

 

Basically you can declutch as fast as you can push the pedal to the floor the shuttle valve offers no resistance but when engaging the clutch it will only return at its own speed even if you sidestep the clutch, there is a tiny metered hole allowing the fluid to return and the master cylinder only has one seal and does not draw fresh fluid from a partial vacuum on the upstroke like a traditional one.

 

I drilled mine out thinking that it was causing my problems and found that the throttle pick up between gearchanges was much faster with virtually no delay for the turbo spooling up, it was not the problem so I have refitted a standard unmodified one to avoid other possible problems.

 

At the very least you should pressure bleed your system from this valve, if the fluid comes out black then you will have a failing master cylinder like I did, any of these particles could restrict the metered hole, indeed there is a high powered magnet on the end of the master cylinder piston which was covered in rubber like remains of my seal which must have had metallic composants in the mix.

 

The clutch master cylinder on RHD models gets very hot from the DPF.

 

Thank you, I shall have a look in the morning.

One piece of good news is the lack of any debris on the end of the master cylinder piston when I looked today 

How did you get it apart to look? I had to cut my old one apart to do an autopsy.

 

An Octopus armed with 6 seperate pointed tools and a puller might be able to release the pressed together plastic assembly but I couldn't.

 

And I'm betting if you had actually removed the master cylinder today for the first time you would not be talking so nonchalantly and your forearms would look like you had been self harming

Scuffing/rumbling was one of the symptoms we had when the clutch finger spring failed and machined the inside of the bell housing.

1 hour ago, weasley said:

Scuffing/rumbling was one of the symptoms we had when the clutch finger spring failed and machined the inside of the bell housing.

 

That thought occurred when I read your earlier post. 

 

On balance, I have no choice but to get a garage to fit a new clutch asap and then deal with whatever else they find.