# Parking Brake Sluggish, Sticking, not releasing fully



## n968412L (Apr 23, 2009)

*Parking Brake Problem*

Anyone had any experience of the Parking Brake not releasing fully and therefore the car thinks it's on, sounds the gong and puts a big red P on the MFI?
I've had this problem a couple of times now. I can cure it by hooking my left foot under the parking brake pedal and just lifting it slightly at the top of its natural travel when operating the release handle. But it certainly makes me not want to put it on. Trip to the workshop required? 
Searched the archive and not found any obvious posts about this.
Thanks
Mike


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## PeterMills (Sep 1, 2006)

*Re: Parking Brake Problem (n968412L)*

Mike,
Never heard of that one.
PETER M


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## Cerdin (Oct 14, 2009)

*Re: Parking Brake Problem (n968412L)*

Hi Mike,
I have had something similar in my 2004 V10 since I was fortunate enough to buy it in April last year. When I 'release' the park brake, I usually have to repeat the action a few seconds later to prevent the gong from sounding. I have regarded it as an irritation rather than a serious problem, but then again I may be over optimistic.
Best - Rhys


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## Cerdin (Oct 14, 2009)

*Re: Parking Brake Problem (n968412L)*

Sorry! I meant 'Hi Peter'! Doh


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## n968412L (Apr 23, 2009)

*Re: Parking Brake Problem (Cerdin)*

Yes - I have had to repeat it in the past... but as of this morning I now have to pull up the foot pedal at the same time....
Good to know I'm not alone!
Regards
Mike


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## Prince Ludwig (Mar 24, 2007)

The only time I've experienced the sticky hand(foot?)brake problem was when taking the car to the Alps and temperatures fell to about -10c at night. Hasn't re-occured since...
Harry


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## vhs (Jun 20, 2006)

I hardly ever use the parking brake except on steep slopes as a back up to the transmission Park position. 
Viv


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## PanEuropean (Nov 3, 2001)

*Re: Parking Brake Problem (n968412L)*


_Quote, originally posted by *n968412L* »_Anyone had any experience of the Parking Brake not releasing fully and therefore the car thinks it's on, sounds the gong and puts a big red P on the MFI?

Hi Mike:
This is a fairly common outcome with many vehicles (from all manufacturers) if the parking brake is not used regularly. The short-term solution is exactly what you discovered (hook your foot underneath it and pull it up) - the long term solution is to ask your VW tech to lubricate the parking brake mechanicals at the wheel hubs (which is where the sluggishness is), then, once that is done, operate the brake once a month or so from that point on.
As long as you can fully release the brake and get rid of the annunciation by hooking your foot under the parking brake pedal, there is no need to make a special trip to the shop.
You may wish to try applying and releasing the brake about a dozen times (don't push it excessivly hard when you do this), and see if that loosens things up. It probably will. But, make a note to get the system lubricated at the next service visit in any case.
Michael


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## PeterMills (Sep 1, 2006)

*Re: Parking Brake Problem (PanEuropean)*

Michael,
Sounds like we should all make a habit of using the parking brake regularly (but not excessively) to mitigate this issue. Would that be your advice? 
It also perhaps may an idea to ask workshops on more 'mature' Phaeton to check that the parking break mechanisms (at the wheel hubs) are lubricated at services.
PETER M


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## car_guy (Aug 19, 2005)

*Re: Parking Brake Problem (n968412L)*

Does this problem present itself at all temperatures, or just when it is below freezing? I used to have a car that did this at say 30 deg. F but not at 34 deg. It required changing a parking brake cable replacement to fix it as evidently water had seeped into it.
Steven


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## PanEuropean (Nov 3, 2001)

*Re: Parking Brake Problem (PeterMills)*


_Quote, originally posted by *PeterMills* »_It also perhaps may an idea to ask workshops on more 'mature' Phaeton to check that the parking break mechanisms (at the wheel hubs) are lubricated at services.

Hi Peter:
I think the latter suggestion - paying more attention to the cable mechanism at scheduled service intervals - is probably the better solution, however, operating the brake monthly is probably the more practical solution.
Michael


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## invisiblewave (Sep 22, 2008)

*Re: Parking Brake Problem (PeterMills)*


_Quote, originally posted by *PeterMills* »_
Sounds like we should all make a habit of using the parking brake regularly (but not excessively) to mitigate this issue. Would that be your advice? 

I work with a bloke who's an ex-Ford mechanic, and I noticed that he always uses the parking brake which is very, very unusual behaviour in the US where practically every vehicle is automatic. When I asked him about it, he said that once you've had a transmission apart and seen the tiny little fork thing that holds the car when it's in Park, you'll always use the brake. I know the ZF transmission is somewhat different from the junk which the other manufacturers use, but the parking brake is designed for parking, just like on a manual car. Interestingly, it's called a hand brake or parking brake in Britain, over here it's always referred to as the "emergency brake", which I've never really understood. Does that mean people use it only when the hydraulic brakes fail???


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## n968412L (Apr 23, 2009)

*Re: Parking Brake Problem (invisiblewave)*

Thanks for all the input on this. It can't quite be lack of use, because I do use it a few times a week.... but mainly for the reason of just keeping it serviceable. I've driven for 30 years+ with hardly ever using one in anger. Very rare that the lowest ratio on a stick shift wouldn't hold a vehicle on most inclines (with the engine off of course), and for automatics, although the pawl that locks the transmission is not big, provided it's not abused in anyway, it's hard to imagine that it could ever fail on a stationery motor.
So, as a frequent, if not always, handbrake user - and frequent to avoid mechanical failures through lack of use - very galling to have this problem today.
But the good news is that it's now mended itself. It's still not convincing... but it's not failed on my commute home.
Next time it is in the workshop I shall certainly command it to be improved!
Thanks again.
Regards
Mike


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## invisiblewave (Sep 22, 2008)

*Re: Parking Brake Problem (n968412L)*

You live in Ramsbottom and rarely use the handbrake???








I always used the handbrake over there, on an hill I'd put it in neutral, put the handbrake on, release the brake pedal, then stick it in first just for safety.
Here, I've got lazy. Texans think 1 in 50 constitutes a steep incline, I can't recall the last time I drove up what I'd consider a hill. The only time I ever use the handbrake is when I park on my drive, which isn't too steep, but it's steep enough to make me feel that the transmission is taking too much strain in Park.


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## Jxander (Aug 5, 2008)

*Re: Parking Brake Problem (n968412L)*

I have the same issue. At this point two pulls are sufficient to release it but one pull is not enough.
I haven't compared the Phaeton to the Touareg on this issue. However, Touareg owners have complained about the same issue and have found that a gas return damper is the source of the complaint. There is a new improved replacement part available for Touaregs. I don't know if it also fits the Phaeton. It is an inexpensive fix. 
Here's the Touareg link.

http://www.clubtouareg.com/for....html


_Modified by Jxander at 1:41 PM 1-20-2010_


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## n968412L (Apr 23, 2009)

*Re: Parking Brake Problem (invisiblewave)*


_Quote, originally posted by *invisiblewave* »_You live in Ramsbottom and rarely use the handbrake???










Grew up and learnt to drive in Blackburn.... not too many hills in Rammy by comparison.

_Quote, originally posted by *invisiblewave* »_
The only time I ever use the handbrake is when I park on my drive, which isn't too steep, but it's steep enough to make me feel that the transmission is taking too much strain in Park. 

Be interesting to get a professional view on this. Again growing up driving landrovers which had a transmssion brake as a parking brake, very used to using that to hold landrover and trailer on some pretty hairy gradients. Landrover handbrakes got a bit of a bad rep, but if they're well maintained (and not full of gearbox oil) they are rock solid (and on all four wheels if you wanted). 
But I'm much happier driving Phaeton's now.







I don't think they have anything in common!
Regards
Mike


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## leedsphaeton (May 27, 2008)

*Sticky Park Brake*

Over the last few days, my car has developed an issue. I release the brake via the pull lever, however it does not fully release the park brake. Instead i have to pull the pedal up with my foot.
Is there a method to lubricate the pedal?


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## Jxander (Aug 5, 2008)

*Re: Sticky Park Brake (leedsphaeton)*

I haven't compared the Phaeton to the Touareg on this issue. However, Touareg owners have complained about the same issue and have found that a gas return damper is the source of the complaint. There is a new improved replacement part available for Touaregs. I don't know if it also fits the Phaeton. It is an inexpensive fix. 
Here's the Touareg link.
http://www.clubtouareg.com/for....html 
1/31/2010 - Just pulled up a diagram of the Phaeton parking brake mechanism. There is no damper to return the brake pedal. Sorry, Touareg solution is inappropriate.








It does appear that the brake pedal assembly must have a spring integrated in it as most of the rest appears to be just cabling. So possibly a bit of lubrication in the right spots might do some good. The real question is where exactly to apply the lubricant.











_Modified by Jxander at 9:59 PM 1-30-2010_


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## Prince Ludwig (Mar 24, 2007)

Hi Masood,
A few other people have had the same problem. The last thread that I remember on the subject is here: http://forums.vwvortex.com/zer...12217
Harry


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## Zaphh (Jul 5, 2008)

*Re: (Prince Ludwig)*

Hi Harry,
I'm having the same problem (sticky park brake) on my May 2004 car, so I have the feeling that the problem is developing...
Even though there is no clear solution to this problem yet, what do you think of putting it in the TOC ?
I am closing to 120Mm where I need to have the belt changed on my V8, so I will point the problem to my dealer, and report what solution they offer.
P.


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## n968412L (Apr 23, 2009)

*Re: (Zaphh)*

Pierre- I do not think it is age related, my Phaeton is MY08, with 20k miles on the clock.
For my money, and I've yet to grovel about in the footwell again, the spring is weak, or the design is poor - in that there is very little spring assistance at the top of the travel. The pedal seems free enough - it take no effort at all to lift it up the little distance needed to clear what ever it is that it sensing its position.
My P my be heading to the workshop again (4th time) to have the boot ECU replaced... it doesn't always open. If I can be bothered to do this soon, I'll ask them why the handbrake doesn't return properly.
Regards
Mike


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## Zaphh (Jul 5, 2008)

*Re: (n968412L)*

Hi Mike (or anyone else),
Any news wrt your sticky parking brake ?
I need to have my car serviced soon, so I would have like to benefit from what your garage found out (does the problem come from a sticky cable, a slow piston of some kind, some spring to change, ...).
Thanks,
P.


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## n968412L (Apr 23, 2009)

*Re: (Zaphh)*

Dear Pierre - apologies but I've made no progress on this... the problem largely cured itself... so I stopped worrying. And it's snowing again so lying on the floor to see what's what with the pedal doesn't appeal. Having said that it did stick again last weekend. If I get round to looking (weather permitting) I'll certainly post my results.
Regards
M


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## PanEuropean (Nov 3, 2001)

*Re: (Zaphh)*


_Quote, originally posted by *Zaphh* »_I need to have my car serviced soon, so I would have like to benefit from what your garage found out (does the problem come from a sticky cable, a slow piston of some kind, some spring to change, ...

Hi Pierre:
Almost always (meaning, 99.38% of the time), stiction in the parking brake control on ANY vehicle is caused by dirt or corrosion of the wire rope cable at the point where it emerges from the cable sheath and enters the rear wheel brake assemblies. The cable is normally made from carbon steel (for strength) - this is why it corrodes. Other materials are not as wear-resistant or as strong.
A good service facility - the kind of place where you buy your car, then take it in once or twice a year for service, and you know them by name and they know you as a regular customer - will automatically operate the parking brake and apply some lubricant to the above-mentioned area. This task is something that falls into the category of 'general due diligence' that is carried out on every scheduled preventative maintenance visit.
The photo below shows the Bowden cable (sheathed cable), the wire rope emerging from the Bowden cable, and the point where corrosion and dirt accumulate if the driver does not ever use the parking brake.
We, as owners, can prevent this problem of 'sticky parking brakes' (meaning, pedal does not pop upwards when release handle is pulled) by simply operating the parking brake once a month. All that we have to do is press it down, then release it - nothing more.
Michael


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## PanEuropean (Nov 3, 2001)

*Re: (PanEuropean)*

*Postscript:*
It is not necessary to disassemble anything to carry out this lubrication, it is not even necessary to remove the wheel and tire. The car only needs to be lifted up, nothing more. It takes at least 30 to 40 seconds to lubricate the moving parts and then function-check the parking brake (20 seconds per side, rear wheels only).
I happened to have a good picture of the rear wheel with the brake caliper removed for service (when I had my rear brakes renewed) - so, I used this photo. 
Michael


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## Zaphh (Jul 5, 2008)

*Re: (PanEuropean)*

I regularly used my parking brake until this winter, when it became sticky.
I asked because I seem to have read somewhere that the problem came from a slow piston...
I know the cable. What do you recommend lubrating it with ?
Thanks for your answer,
P.


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## leedsphaeton (May 27, 2008)

I found a much simpler fix, I engaged and released the park brake, around 10 times continiously, and the problem has not reoccured since.


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## PanEuropean (Nov 3, 2001)

*Re: (leedsphaeton)*

That will work too...


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## n968412L (Apr 23, 2009)

*Re: (PanEuropean)*

Masood's solution was the one I tried first - as it works for many other mechanical things.. .but didn't solve my problem.
I note Michael's point about the cable at the wheel.. and I'm sure this is generally good advice... particularly as my problem started after washing the car, and then it freezing over night. So... a combination of water swelling the pads and freezing too is a recipe for stiction... but I have to say I really think the problem for me is at the other end in that it only needs me to lift the foot pedal by about 5mm (and to which there is no resistance) for the alarm to cancel. Given that if the cable was sticking I'm not sure I'd be able to lift the pedal... I'm not sure the problem is at the wheel end.
But happy to be proved wrong! I must get back out and grovel on the floor and have a look!
M


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## Jxander (Aug 5, 2008)

*Re: (n968412L)*

Mike:
Mine has never stuck to the point where I have to lift it with my foot. But I was experiencing a need to pull the release lever two times before it fully released. I could see where the inner cable goes into its outer case and applied a little lock lubricant. I have not lubricated at the other end near the wheel which is exposed to the elements but I do plan to do that also. 
I have noticed that I have become accustomed over the years to merely "pop" the brake release lever and on the Phaeton it seems better to pully it gently but fully(don't pull too hard for fear of stretching the cable). I could be wrong but I bet you will get better performance if you pull the brake release fully and hold it there momentarily to allow time for the emergency brake pedal to return. However, good lubrication and possible adjustment(surely its adjustable somewhere to account for modest cable stretch) might be the only long-term cure.
Pooling our collective wisdom, we should be able to resolve this common issue.


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## PanEuropean (Nov 3, 2001)

*Re: (Jxander)*


_Quote, originally posted by *Jxander* »_...I was experiencing a need to pull the release lever two times before it fully released. 

That's an interesting observation. When my Phaeton was new (and I mean seriously new, as in 1 or 2 months after delivery), I noticed the same thing - sometimes, I had to pull the release handle twice before the park brake would release.
This might indicate that I was not holding the release lever out for a suitable period of time, or perhaps I was not pulling it far enough out, or perhaps there was some other thing influencing release of the parking brake. I guess I must have intuitively figured out that I was doing something wrong and adjusted my technique, because the problem went away after the first couple of months of ownership and has never returned.
Michael


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## n968412L (Apr 23, 2009)

*Re: (PanEuropean)*

Can't quite describe this properly... will concentrate on it when next releasing the brake, but I agree... I'm concious I do have to pull the release slowly and hold it at the full release position longer than my natural instinct is....


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## Zaphh (Jul 5, 2008)

*Parking Brake Problem (to be added in the TOC ?)*

At the beginning of the winter, when temperatures went below 0°C, my parking brake pedal would not release when pulling on the handle.
Since I was to have my car checked in March to get the French equivalent of an MOT (they call it a "technical control", do you have such a thing in the US ?) and since I saw that some of you never used the parking brake (Michael included, I think), and since I was really busy, I thought I would have the garage sort it out in March, and decided not to apply the parking brake anymore and keep the car in P.
In the beginning, there was no play whatsoever in the transmission. When I put the car in P mode and released the bake pedal, it would stay where it was.
Now, at the end of the winter, there is some noticeable play in that whenever I put the car in P and release the brake pedal, the car will move several inches forward or backward before being stopped by whatever stops it when the car is in P.
Last week, weather was good (14-17°C) and the brake pedal released fine and normally (at full speed). I went to the dealer, and as the car was up, I told them about the problem of having a stuck parking brake at freezing temperatures, and forwarded Michael's opinion that 99% of the chances were that the cable would be corroded, and that adding a bit of lubricant would do the trick...
He sprayed some lubricant while saying that normally, there is a rubber seal that would prevent any water from getting there, so he didn't think the problem came from there.
This week, we have freezing temperatures again, and again, the parking brake is stuck.
However, I found out (as was said on the forum several times) that by pulling the pedal with my foot, the parking brake would be released. This makes me think that indeed, the problem is not with the cable on the rear brake end, but something else (maybe the release mechanism on the pedal side).
Anyway, I am now worried with the play that developed since I used the P mode instead of the parking brake.
When the car was up at the dealer's, I tried to move the rear and front wheels by hand. There is not that much play in the rear, but a huge play in the front (I could rotate one wheel for maybe PI/6 or PI/4 radians (30 to 45°) before the other wheel would turn in the other direction, with a horrible "clunk" in the differential...
I asked the tech about this, but he said that it was normal that such play developed in the front, and unless I felt some thuds while driving, I would not have to worry about it...
Well, knowing all the transmission problems that occur on this car, I'm not that happy with this...
Can anyone on the forum tell me what they think ?
To finish on the transmission topic, I was surprised to see that I was able to get the rear wheels to turn (in the same direction) without getting the front wheels to turn.
Isn't there a physical Torsen differential between the front and rear wheels ? I know it is proactive, meaning that it transfers more power on the wheels that can use it, so would this result in allowing the front wheels to turn without getting the rear wheels to turn ?
This question is also important, as when 2 years ago, my car wouldn't start due to a defective (corroded) kessy module, I put the car in Neutral with the guy so that it would move, and the guy put 2 dollies under the front wheels, and we pushed it to the platform although I told him it was a 4WD. The guy said it was not a problem and indeed, we could push the car on 50 yards (here again, I would have expected the rear wheels to be connected to the front via the Torsen differential, and therefore, expected the front wheels to turn in the dollies when the rear wheels turned on the ground).
Quite many subjects in this post (could have been better if I had split it in 2 or 3 posts maybe).
To sum up:
1) anyone has a suggestion on the problem with the parking brake release mechanism at freezing temperatures (I think the cable is ruled out).
2) Anything to worry about concerning the play that has developed in the transmission while I used the P position instead of the parking brake ?
3) how could the front and rear wheel not be connected whatsoever, even though it is a 4WD ?
Thanks,
P.


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## Prince Ludwig (Mar 24, 2007)

*Re: Parking Brake Problem (Zaphh)*

Hi Pierre,

_Quote »_1) anyone has a suggestion on the problem with the parking brake release mechanism at freezing temperatures (I think the cable is ruled out).

I've only experienced the sticky parking brake once (in France strangely!) and that was when skiing so it was both wet and cold (-8 degrees c). Although I haven't investigated in more detail, given the fact that temperature seems to be a key factor I wonder whether it could be due to some lubricant gelling somewhere.

_Quote »_2) Anything to worry about concerning the play that has developed in the transmission while I used the P position instead of the parking brake ?

I'm not sure how the transmission in the Phaeton implements the parking brake but, as far as I'm aware, the usual mechanism is to extend a tooth into notches on the outside of the housing for the gear clutches. The small amount of movement you get could just be the housing slipping until the tooth engages. It could always have been like that and you've only noticed once you started paying it close attention







. Either way, I'll test mine and see how it performs.

_Quote »_3) how could the front and rear wheel not be connected whatsoever, even though it is a 4WD ?

Assuming all brakes are off and the gearbox is in park, if you turn one of the front or rear wheels, the other should turn in the opposite direction. If both wheels on one axle are turned in the same direction, the torsen will behave like an open differential and the wheels on the other axle will turn in the opposite direction. If, however, the gearbox is in neutral, the torsen will take the path of least resistance (which I assume would be the gearbox) so you won't get any movement on the opposing axle. I'll have a think about this, though, since the mechanical principle of torsens is not especially intuitive








Harry


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## adamkodish (Mar 5, 2006)

*Re: Parking Brake Problem (Prince Ludwig)*


_Quote, originally posted by *Prince Ludwig* »_Hi Pierre,
I've only experienced the sticky parking brake once (in France strangely!) and that was when skiing so it was both wet and cold (-8 degrees c). Although I haven't investigated in more detail, given the fact that temperature seems to be a key factor I wonder whether it could be due to some lubricant gelling somewhere.
Harry

I had this happen the other night when the temperature was about -2C.
This was the first time I've seen the problem and I use the parking brake at the end of each trip. Pulling the handle again released the brake.
Adam


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## Prince Ludwig (Mar 24, 2007)

Sorry, that should have read "sticky hand brake".
HH


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## Zaphh (Jul 5, 2008)

*Re: Parking Brake Problem (Prince Ludwig)*


_Quote, originally posted by *Prince Ludwig* »_Hi Pierre,
...
I'm not sure how the transmission in the Phaeton implements the parking brake but, as far as I'm aware, the usual mechanism is to extend a tooth into notches on the outside of the housing for the gear clutches. The small amount of movement you get could just be the housing slipping until the tooth engages. It could always have been like that and you've only noticed once you started paying it close attention







. Either way, I'll test mine and see how it performs.
...
Harry

Nope. I'm quite sure the play developed ever since I stopped using the parking brake. I remember being impressed when I first parked without using the parking brake that there was virtually no play. I would put the car in P and it would stay there. I wondered how the tooth could happen to be in front of the notch whatever the position I stop in.
Now, as I said, the car can go forward or backward (depending on the slope) a good 5 to 10 inches (I would say, but did not measure it). Now, maybe my transmission developed this over the very same period coincidentally, and this may not have anything to do with my stopping to use the parking brake, but I would swear things are related.
From now on, freezing temperatures or not, until the sticky parking brake problem is solved, I will use it, to the risk of damaging the top of my shoes by retracting the pedal by pulling it with my foot.
I will get the dealer to have a look at it, but my next appointment will be at 120Mm and this will not be before a couple of months so by then, freezing temperatures will be long forgotten, and the problem will have disappeared.
So let's say I'll try to get the problem solved next winter, when it reappears...








P.


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## PanEuropean (Nov 3, 2001)

*Re: Parking Brake Problem (Zaphh)*

Below is an illustration that shows the construction and operation of the park lock feature that is built into the 6 speed transmission. It is quite straightforward and very typical, simply a pawl that fits into a cog wheel to stop the rear portion of the driveline from turning.
Michael


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## n968412L (Apr 23, 2009)

*Re: Parking Brake Problem (Prince Ludwig)*


_Quote, originally posted by *Prince Ludwig* »_
I'll have a think about this, though, since the mechanical principle of torsens is not especially intuitive








Harry

Too damn right! This might help:
http://www.torsen.com/files/Tr...e.pdf
Or it might not!
I think Harry's right... if the transission is locked, turning both back wheels should counter rotate the front wheels - although I think the Torsen will multiply the resistance and make it feel very stiff. If the trasmission is in neutral, then dependent on the box resistance, I'd expect the front wheels to turn in the opposite direction... but not as fast - ie a differential effect with the box turning a bit.... but here I'm really taxing my imagination with how the damn thing works.
As far as Pierre's experience of float in the transmission, mine (21k miles) has always floated - and being used to vehicles with transmission brakes, was not fazed by this at all. Not sure where the final diff is in relation to the brake on the gear box, but there is probably two diffs between the brake and the wheels - so I would have expected quite a bit of "slop". This is definitely more marked on a gradient - as you might expect. I would think that my Phaeton rolls 4 or 6 inches before the float is taken up. To me this seems perfectly normal for a transmission brake and I'd not worried about it... but I'm only assuming that this is normal for Phateons.... I don't know.
Again my experience of "agricultural" open diffs is that PI/6 was quite normal to turn one wheel before the other starte to turn in the opposite direction..... but again I might have expected a bit more precision from a Phaeton.
Fascinating....


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## Zaphh (Jul 5, 2008)

*Re: Parking Brake Problem (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_Below is an illustration that shows the construction and operation of the park lock feature that is built into the 6 speed transmission. It is quite straightforward and very typical, simply a pawl that fits into a cog wheel to stop the rear portion of the driveline from turning.
Michael

Ok. So I take it from the illustration that no play can come from the pawl into the cog wheel.
Now, how is the cog wheel connected to the wheels ? Any possibility of getting some play to grow in between the cog wheel and the wheels ?
As for the front wheels not turning when the rear wheels are turned (in the same direction), I can assure you both front and back axles seem to be disconnected. Now this is when the car is in Neutral.
Would it be different if a gear was engaged ?
P.


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## Prince Ludwig (Mar 24, 2007)

_Quote, originally posted by *n968412L* »_I think the Torsen will multiply the resistance and make it feel very stiff

I think you might be on the money here although I'd go further and say that the torsen wouldn't allow any movement.
The basic principle that the torsen diff operates on is that a worm gear (the grey bit in the photo below) can drive a worm wheel (the gold bit) but not vice-versa








The thing that took me a while to get my head round with the torsen diff is that, despite appearances, the gear that connects to the drive shaft is the worm gear and the planet gears are the worm wheels:








Therefore, if the differential housing is locked (gearbox in park) and you turn both rear wheels in the same direction, the driveshaft will turn and try to drive the rear planet gears. However, because the front and rear planet gears are connected through the spur gears, they won't be able to move because the front planet gears cannot drive the front axle (a worm wheel can't drive a worm gear). If, however, you rotated the front wheels in the opposite direction to the rear wheels at the same time, then all wheels would rotate freely.
I hope that makes sense, as I said the torsen is not very straightforward to explain!
HH


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## n968412L (Apr 23, 2009)

*Re: (Prince Ludwig)*

Harry - I largely agree with you... and freely admit you might be right - because it is hard to visualize. We need to get hold of one and have a play.....
But, and my thoughts are informed by the PDF I attached to my previous post, dependent on the angle of the teeth on the worm I wonder if the reverse drive is not possible. I do agree that for the worm/worm gear combination you have drawn, the gear can't turn the worm... but the angle between the worm teeth and the worm wheel axis looks to be less in the diff than in your drawing. And if you also compare the hypoid gears in the diff (not drawn here) - ie the crown wheel and pinion - because of the off axis arrangement that's much more like a worm... but clearly does work both ways. So I'm not sure....
The other aspect that makes me think it works both ways... in your excllenent drawing... consider holding the LH half shaft fixed whilst the input shaft turns. Clearly the pinions will rotate and the worm on the RHS will turn the RH half shaft..... but from a relative point of view, is the LH half shaft turning its pinion...?? depdends on you point of view but I think it is. And a locked LH half shaft is only the extreme case - any differential rotation, from one point of view, could be the half shaft driving the pinions.... I guess it's which shaft do you take as your reference point. But happy if someone can see a dreadful solecism in my logic...
I'll have to keep my eyes open for the opportunity to find one in the wild so I can have a play with it.... 
Regards
M


_Modified by n968412L at 9:59 PM 3-8-2010_


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## PanEuropean (Nov 3, 2001)

*Re: Parking Brake Problem (Zaphh)*


_Quote, originally posted by *Zaphh* »_...So I take it from the illustration that no play can come from the pawl into the cog wheel...

I don't think that is a safe assumption. First, there has to be a little bit of play designed into the pawl, otherwise, you would never get the vehicle out of Park if you had parked the car on an incline and there was slight tension on the pawl (in other words, if the pawl was holding the car).
Second, it is not unreasonable to expect that the pawl will wear a bit with time. I don't think you would get a huge amount of slop in the assembly - the amount of backlash is limited by the distance between the gear teeth - but you could get some backlash developing as the pawl wears.
Michael


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## Zaphh (Jul 5, 2008)

*Re: Parking Brake Problem (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_
... but you could get some backlash developing as the pawl wears.
Michael

Yes, but probably not as much as going from unnoticeable to 5 - 10 inches forward or backward...
There has to be another spot where play can develop...
What about your car (or someone else's car) ? What amount of backlash is there on a car where the parking brake is never used ?
P.


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## PanEuropean (Nov 3, 2001)

*Re: Parking Brake Problem (Zaphh)*

Maybe a couple of inches (5 cm).
Michael


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## n968412L (Apr 23, 2009)

*Re: Parking Brake Problem (Zaphh)*

Dear Pierre - my opinion, stress opinion not fact, is that the play you are witnessing is entirely normal. I would agree that my Phaeton could easily be moving 8 inches when in Park with handbrake not applied. As I said earlier, this has been about normal for my experience of transmission brakes - and it's mainly the float in the differentials. Here, I think, there are two differentials in series - so twice the slop.
I only make this point because I think you might be mentally torturing yourself about a mechanical problem that is not real... although of course if I was you I'd be seeking indepenent corroboration rather than rely on some soothing words from a moron in a chat room (ie me).
Incidentally when Harry was drawing me into Torsen complexities, I'd overlooked the bit in your post where you say that you moved the car with the front wheels on dollies and the transmission in neutral... I think I'd like Harry to say whether he thinks lines up with his thoughts on how Torsen works. I think I'm perfectly happy with this -but I think Harry was implying that this probably was not possible? But this is so complex I could be quite wrong!
But bakc to your problem... I hope you can get some one else to help put your mind at rest... or set you on the right path to a repair.
Regards
M


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## Prince Ludwig (Mar 24, 2007)

_Quote »_Incidentally when Harry was drawing me into Torsen complexities, I'd overlooked the bit in your post where you say that you moved the car with the front wheels on dollies and the transmission in neutral... I think I'd like Harry to say whether he thinks lines up with his thoughts on how Torsen works. I think I'm perfectly happy with this -but I think Harry was implying that this probably was not possible? But this is so complex I could be quite wrong!

As long as the transmission was in neutral there shouldn't be any problems - an input from one of the drive shafts can't turn the other shaft (due to the lock-up of the planet gears) so will try and turn the entire differential housing which, if the gearbox is in neutral, will just spin freely.
Harry


_Modified by Prince Ludwig at 11:42 AM 3-9-2010_


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## n968412L (Apr 23, 2009)

*Re: (Prince Ludwig)*

Sorry Harry - my mistake. You did say this in a previous post. Have you any "hands on" experience of a Torsen diff - ie do you absolutely know your right about the lock up aspect, or is it an assumption based on your assessment of the design?
Cheers
M


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## Prince Ludwig (Mar 24, 2007)

The latter although I'm pretty confident that I've made the right assumptions about the design - if the planet gear (worm wheel) could drive the side gear (worm wheel), the design wouldn't work as intended (I think!)
Harry


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## n968412L (Apr 23, 2009)

*Re: (Prince Ludwig)*

And I think something different... but only a little. Hope we can resolve it sometime!
I think we're both right really... it's just a question of degree. I think one half shaft can drive another... but only with significantly more torque... ie the torque is lost in the diff... which presumably means a lot of heat under heavy slippage... so mabye I am wrong.... but it's this torque difference, or bias, that the worm gears provide.
What do you think of my simily with the hypoid crow and pinion? Is that not similar to the Torsen worm wheels? 
Going to bed now... has made my head hurt. Suggest we only carry this on when we've got access to a physical implementation of the diff that we can play with!
Regards
M


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## Zaphh (Jul 5, 2008)

*Re: Parking Brake Problem (n968412L)*


_Quote, originally posted by *n968412L* »_Dear Pierre - my opinion, stress opinion not fact, is that the play you are witnessing is entirely normal. I would agree that my Phaeton could easily be moving 8 inches when in Park with handbrake not applied. As I said earlier, this has been about normal for my experience of transmission brakes - and it's mainly the float in the differentials. Here, I think, there are two differentials in series - so twice the slop.
I only make this point because I think you might be mentally torturing yourself about a mechanical problem that is not real... although of course if I was you I'd be seeking indepenent corroboration rather than rely on some soothing words from a moron in a chat room (ie me).
Incidentally when Harry was drawing me into Torsen complexities, I'd overlooked the bit in your post where you say that you moved the car with the front wheels on dollies and the transmission in neutral... I think I'd like Harry to say whether he thinks lines up with his thoughts on how Torsen works. I think I'm perfectly happy with this -but I think Harry was implying that this probably was not possible? But this is so complex I could be quite wrong!
But bakc to your problem... I hope you can get some one else to help put your mind at rest... or set you on the right path to a repair.
Regards
M

The problem is that I'm really under the impression that the slip *developed* between november and now, i.e. during the period where I stopped using the parking brake systematically as I have always done before.
Now, you all make me doubt. Maybe it was there from the start (but my other car being an automatic Citroen XM which shows the same play in the transmission when in Park without the parking brake), I clearly recall being positively surprised at how small the slack was on the Phaeton...
So it may be my memory.
Anyway, since there is no clunking when the car is running, I'm quite happy with this.
P.


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## Youkouman (Dec 13, 2011)

*Park brake Release Handle*

Its exactly the same for me! Since I replaced the first one that broke, I've been having to support the release of the Parking brake with my left foot.

Now, the handle has broken again... Quite annoying.

2. Why do my fuel pumps keep dying on me???? Anybody???

3. Is there any way to repair a faulty Trunk support strut?

Please help.....


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## invisiblewave (Sep 22, 2008)

Do you run the car to empty before filling the petrol tank?


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## xoxkarly (Oct 6, 2013)

Thank you SO much for posting that tip on tapping the parking brake. My 04 Touareg's wouldn't come completely off, googled the problem and found your thread. Made an account just to say thanks a million once again! Saved me a lot of stress


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