Clutch adjustment

[roadsterdoc]

The clutch actuation occurs in the 1st 10% of the pedal travel. In other words, when the pedal is almost all the way away from the floor. It is really annoying as it makes it difficult to drive smoothly. There must be a way to adjust it so that the actuation occurs closer to the middle of the pedal throw. I have searched found nothing.

Thanks for any help!

Chris

2001 996TT

Houston TX

[Loren]

The clutch on your car is hydraulic. For it to be that far off likely means that there is air in the lines or you have a leak. Have you checked the fluid level?

You will likely have to take the black plastic cover off to see the fill marks on the reservoir. It is the Green cap in front luggage compartment - if it is low use Pentosin CHF 11 S hydraulic fluid (not brake fluid).

In a few cases the clutch spring has failed and the pedal will (dramatically) go to the floor when pressed.

[roadsterdoc]

Thanks Loren. I checked the resevoir and it is full. Correct me if I am wrong, but if there were air in the line wouldn't it engage when the pedal is on the floor instead of at the top of the stroke?

Edited April 29, 2006 by roadsterdoc

[Loren]

Air does funny things depending on the amount and the compression.

Has the circuit been open for anything? bleeding or leak?

If it were my car I'd try bleeding it and see if it changes.

[boli 996]

The clutch actuation occurs in the 1st 10% of the pedal travel. In other words, when the pedal is almost all the way away from the floor. It is really annoying as it makes it difficult to drive smoothly. There must be a way to adjust it so that the actuation occurs closer to the middle of the pedal throw. I have searched found nothing.

Thanks for any help!

Chris

2001 996TT

Houston TX

Procedure to check clutch pedal:

Clutch: checking the play and pedal end position

- Checking clutch free play

- Checking the pedal end position (pedal return/return force)

- Checking clutch free play

The clutch master cylinder has an inner stop. The push rod and the clutch pedal are always pressed against this

stop by the boost spring. Due to the automatic hydraulic adjustment of the clutch, it is not possible to

determine the clutch play by checking at the clutch pedal.

top of page

Checking the pedal end position (pedal return/return force)

- Check that the pedal is in end position by pulling at the pedal (without the use of force) towards the

driver's seat.

Note

· The pedal must not give way during the process.

· If it gives way, the fault is in the boost spring or in the pedals.

The clutch push rod and the boost spring are not adjustable. The boost spring has 2 functions, namely to

provide pedal force assistance and to return the pedal. The following are some of the points which are

requirements for perfect clutch operation:

· Correct bleeding of the clutch hydraulics.

· No leaks in the hydraulic system.

· Pedal return to the starting position.

· Installation position of the pedals in accordance with the series condition.

Edited April 29, 2006 by boli 996

[roadsterdoc]

Thank you 'boli 996' for posting. I followed the instructions the best I could but they are a little difficult for me to understand. What, for example, does "Installation position of the pedals in accordance with the series condition" mean?? It sounds like it was translated into 3 other languages before english! :P

I picked up a can of Pentosin CHF 202 from the dealership today (it says power steering oil). I will attempt to bleed the clutch system. I assume that the standard 2-person bleeding technique is appropriate (depress pedal, open valve, close valve, release pedal and repeat).

[boli 996]

The instruction text is copied from a workshopmanual (I will not print the manufactor).I think the translation had been done from German into english.

"Installation position of the pedals in accordance with the series condition" mean??

-I think they mean that You have to check the installation of the pedals, (not correct installed as it should be).

I don't know if it's possible to You any other type of oil than Pentosin CHF 11 S.

To bleed the system,see attachment

You have got mail

Microsoft_Word___Dokum.pdf

Edited April 30, 2006 by boli 996

[1999Porsche911]

If I understand your probem correctly, you do not like that the clutch engages so far from the floor. In this case, the easy fix is to introduce air into the hydraulic system. Depress the pedal a few inches and open the bleeder on the slave. Pull the pedal to the top and close the bleeder.

This will introduce a little air to the system and your pedel travel will remain the same but it will have increased free travel at the top and engage closer to the floor. Repeat until the pedal engages where you want. Much easier to drive this way.

[roadsterdoc]

The Porsche parts guy said the CHF-202 replaces the CHF-11S, but you raise a good question. A google search came up with this about Pentosin:

Joel Reiser - PCA WebSite - 2/6/2006 wrote:

"...Another point worth mentioning is that there has been some confusion about Pentosin products. Some people say "Pentosin" as if that automatically means "hydraulic oil", and then they go and use Pentosin brake fluid where Pentosin's hydraulic oil CHF-11S and CHF-202 are specified for the power steering, or vice versa. This is really really bad, since the two systems are not compatible. Pentosin is a brand name of a company that makes fine products, but we can't be careless when we decide where to pour each into the car.

CHF-11S and CHF-202 are compatible, those are the older and newer versions of the hydraulic oil used for power steering. But neither of those two Pentosin products are compatible with Pentosin's (or anyone else's) brake fluid. "

Regarding '1999Porsche911s' suggestion to add air to the system, that may yield the results I want...but I'm reluctant to do so and would be surprised if this is the only solution (I've been wrong before!). I'll try to bleed it today and post the results.

[1999Porsche911]

The Porsche parts guy said the CHF-202 replaces the CHF-11S, but you raise a good question. A google search came up with this about Pentosin:

Joel Reiser - PCA WebSite - 2/6/2006 wrote:

"...Another point worth mentioning is that there has been some confusion about Pentosin products. Some people say "Pentosin" as if that automatically means "hydraulic oil", and then they go and use Pentosin brake fluid where Pentosin's hydraulic oil CHF-11S and CHF-202 are specified for the power steering, or vice versa. This is really really bad, since the two systems are not compatible. Pentosin is a brand name of a company that makes fine products, but we can't be careless when we decide where to pour each into the car.

CHF-11S and CHF-202 are compatible, those are the older and newer versions of the hydraulic oil used for power steering. But neither of those two Pentosin products are compatible with Pentosin's (or anyone else's) brake fluid. "

Regarding '1999Porsche911s' suggestion to add air to the system, that may yield the results I want...but I'm reluctant to do so and would be surprised if this is the only solution (I've been wrong before!). I'll try to bleed it today and post the results.

A hydraulic clutch system without an adjustable piston either at the slave or the pedal will always engage at the top of the pedal if the system is free of air. No matter how high or low you adjust the pedal, the engagement will still be at the top of the pedal release. Only by somehow establishing play in the hydraulic system can you reduce the level at which the clutch will engage. On a cable controlled clutch, this was accomplished by indroducing slack into the line. With hydraulics, the fluid is the cable and without adjustable pistons, the only way you can introduce slack is to intoduce air. This allows the pedal to be pressed down further before the line is compressed enough to begin working. It is a perminant and dependable solution and has been a standard way of adjusting hydraulic clutches since they were first introduced.

Edited April 30, 2006 by 1999Porsche911

[Kiko]

Whats the mileage on that clutch? As the clutch dics gets worn the pedal comes up. Maybe you need to change the clutch.

The Porsche parts guy said the CHF-202 replaces the CHF-11S, but you raise a good question. A google search came up with this about Pentosin:

Joel Reiser - PCA WebSite - 2/6/2006 wrote:

"...Another point worth mentioning is that there has been some confusion about Pentosin products. Some people say "Pentosin" as if that automatically means "hydraulic oil", and then they go and use Pentosin brake fluid where Pentosin's hydraulic oil CHF-11S and CHF-202 are specified for the power steering, or vice versa. This is really really bad, since the two systems are not compatible. Pentosin is a brand name of a company that makes fine products, but we can't be careless when we decide where to pour each into the car.

CHF-11S and CHF-202 are compatible, those are the older and newer versions of the hydraulic oil used for power steering. But neither of those two Pentosin products are compatible with Pentosin's (or anyone else's) brake fluid. "

Regarding '1999Porsche911s' suggestion to add air to the system, that may yield the results I want...but I'm reluctant to do so and would be surprised if this is the only solution (I've been wrong before!). I'll try to bleed it today and post the results.

A hydraulic clutch system without an adjustable piston either at the slave or the pedal will always engage at the top of the pedal if the system is free of air. No matter how high or low you adjust the pedal, the engagement will still be at the top of the pedal release. Only by somehow establishing play in the hydraulic system can you reduce the level at which the clutch will engage. On a cable controlled clutch, this was accomplished by indroducing slack into the line. With hydraulics, the fluid is the cable and without adjustable pistons, the only way you can introduce slack is to intoduce air. This allows the pedal to be pressed down further before the line is compressed enough to begin working. It is a perminant and dependable solution and has been a standard way of adjusting hydraulic clutches since they were first introduced.

[roadsterdoc]

Only 24,700 miles on the car and there is no slippage whatsoever.

I have not had time to bleed the system yet, or to add air. The thought of air in the lines disturbs me but I guess it's not a big deal as long as it is the clutch and not brake lines! I'm still not sure it will cure the abrupt transition problem...only move the transition to the middle of the stroke (which would be some improvement).

Thanks guys...keep the thought coming!

[1999Porsche911]

Only 24,700 miles on the car and there is no slippage whatsoever.

I have not had time to bleed the system yet, or to add air. The thought of air in the lines disturbs me but I guess it's not a big deal as long as it is the clutch and not brake lines! I'm still not sure it will cure the abrupt transition problem...only move the transition to the middle of the stroke (which would be some improvement).

Thanks guys...keep the thought coming!

The abruptness is most likely caused by where the pedal is when the pressure plate kicks the actuator arm out all the way. In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible. Lowering the engagement point of the pedal will reduce the pull effect of the boost spring. Or you can eliminate it all together by removing the spring and drive the car without pedal assiatnce. Much smoother, Removing the spring is also the best way to feel the movement of the entire clutch system for diagnossis.

Edited May 5, 2006 by 1999Porsche911

[roadsterdoc]

The abruptness is most likely caused by where the pedal is when the pressure plate kicks the actuator arm out all the way. In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible. Lowering the engagement point of the pedal will reduce the pull effect of the boost spring. Or you can eliminate it all together by removing the spring and drive the car without pedal assiatnce. Much smoother, Removing the spring is also the best way to feel the movement of the entire clutch system for diagnossis.

Aha! Now we are getting somewhere: "...In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible..." I think this describes the crux of the problem which is my primary complaint.

Two questions:

How do I lower the engagement point of the pedal?

Where is the spring...is it on the slave cylinder?

[1999Porsche911]

The abruptness is most likely caused by where the pedal is when the pressure plate kicks the actuator arm out all the way. In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible. Lowering the engagement point of the pedal will reduce the pull effect of the boost spring. Or you can eliminate it all together by removing the spring and drive the car without pedal assiatnce. Much smoother, Removing the spring is also the best way to feel the movement of the entire clutch system for diagnossis.

Aha! Now we are getting somewhere: "...In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible..." I think this describes the crux of the problem which is my primary complaint.

Two questions:

How do I lower the engagement point of the pedal?

Where is the spring...is it on the slave cylinder?

Crawl under the dash and have a look. The spring's main purpose it to assit pushing the pedal to the floor and NOT bring it to the top. Easy to remove, but make sure you put a small nail or pin in the end hole provided in the piston so the spring does not pop out when removed. Then drive the car with it removed and you'll get the correct feel for the cutch mechnism.

However, try simply reducing the engagement point of the pedel as I descibed above by introducing air into the system. This, by itself, may move the pedal to a point where the spring does not interfere. My pedal, which engaged at the top with the new stage 2 clutch, now engages about half way up. Play with it until you get a comfortable engagement point. You'll be surprised how much smoother your shifting is.

[ebaker]

The clutch may be worn. The pedal gets higher as the lining gets thinner. A clutch system that has air will have a low pedal.

Edited May 20, 2006 by ebaker

[roadsterdoc]

Here's a late follow up post. I took the car to a seasoned Porsche mechanic and he said yes indeed, it is high off the floor but it is within normal limits. He estimates the wear at 60% and that I should leave it as-is. Honestly, I am looking forward to wearing it out and getting a replacement!

[Gabriel]

However, try simply reducing the engagement point of the pedel as I descibed above by introducing air into the system. This, by itself, may move the pedal to a point where the spring does not interfere. My pedal, which engaged at the top with the new stage 2 clutch, now engages about half way up. Play with it until you get a comfortable engagement point. You'll be surprised how much smoother your shifting is.

I have a 2002 996 and the clutch also engages fairly high. I tried removing the boost spring but couldn't get it out. In any case, the technique 1999Porsche911 is recommending sounds a lot better, as it will lower the engagement point which will make removing the spring an unnecessary thing. I am concerned about this technique, though. Why is it no one else recommends this? Doesn't introducing air create a spongy pedal feel? Any other side effects? Doesn't this go contrary to the notion of bleeding the hydraulic system?

[fastboydave]

I cant believe what i've read above?? Under NO circumstances should AIR be introduced to any hydraulic system! If you have an issue with your clutch, it is because either air IS in the system already, your clutch is wearing out, or there is some other problem. You dont 'fluff' something to treat the symptoms, you solve the route cause. Air is unpredictable and over the course of time changes. Let me ask a question, would you introduce AIR into your brake system?? NO, thought not! So there is your answer.

I have had air in my clutch system (not by choice) and the pedal/bite goes to the floor, NOT the other way round. Also the 'bite' becomes 'unpredictable' in that the bite position keeps changing. I suggest that if your bite is high, your clutch is on the way out. I think that i have read on here there is slight adjustment you can make, but only slight, so book it in for a clutch job. Done.

[miguel oliveira]

Hi

I have a 2003 996TT, and I feel the same with the clutch only working in the last part, the car has 42000 kms and the pedal feels very light , I would like to try to put some air but I dont Know where is the bleeder for the clutch.

Does anyone has pics or detail instructions

Thank you all

[Loren]

The bleeder is mounted high on the transmission slave cylinder.

Unless you have a lift you will need to remove the left rear wheel to get to it.

[miguel oliveira]

The bleeder is mounted high on the transmission slave cylinder.

Unless you have a lift you will need to remove the left rear wheel to get to it.

Thanks Loren

Do you have any pictures so I can find it more easy

[Loren]

Sorry, I don't have any pics.

It is very on the transmission - and looks just like a brake bleed screw.

[Gabriel]

I cant believe what i've read above?? Under NO circumstances should AIR be introduced to any hydraulic system! If you have an issue with your clutch, it is because either air IS in the system already, your clutch is wearing out, or there is some other problem. You dont 'fluff' something to treat the symptoms, you solve the route cause. Air is unpredictable and over the course of time changes. Let me ask a question, would you introduce AIR into your brake system?? NO, thought not! So there is your answer.

I have had air in my clutch system (not by choice) and the pedal/bite goes to the floor, NOT the other way round. Also the 'bite' becomes 'unpredictable' in that the bite position keeps changing. I suggest that if your bite is high, your clutch is on the way out. I think that i have read on here there is slight adjustment you can make, but only slight, so book it in for a clutch job. Done.

I find it surprising the variance of opinions on this topic. Most people seem to agree that introducing air is not a good idea, though. But it seems that for at least one person that has worked categorically well. How can that be?

[btrapps]

The abruptness is most likely caused by where the pedal is when the pressure plate kicks the actuator arm out all the way. In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible. Lowering the engagement point of the pedal will reduce the pull effect of the boost spring. Or you can eliminate it all together by removing the spring and drive the car without pedal assiatnce. Much smoother, Removing the spring is also the best way to feel the movement of the entire clutch system for diagnossis.

Aha! Now we are getting somewhere: "...In certain positions, this upward pressure on the pedal along with the pivot of the pedal boost spring will make smooth release of the pedal nearly impossible..." I think this describes the crux of the problem which is my primary complaint.

Two questions:

How do I lower the engagement point of the pedal?

Where is the spring...is it on the slave cylinder?

Crawl under the dash and have a look. The spring's main purpose it to assit pushing the pedal to the floor and NOT bring it to the top. Easy to remove, but make sure you put a small nail or pin in the end hole provided in the piston so the spring does not pop out when removed. Then drive the car with it removed and you'll get the correct feel for the cutch mechnism.

However, try simply reducing the engagement point of the pedel as I descibed above by introducing air into the system. This, by itself, may move the pedal to a point where the spring does not interfere. My pedal, which engaged at the top with the new stage 2 clutch, now engages about half way up. Play with it until you get a comfortable engagement point. You'll be surprised how much smoother your shifting is.

Sorry to bring this back from the dead.. Has anyone removed this helper spring and likes the feel more of the clutch pedal?