Incomplete clutch disengagement problem

[oldchevyguy]

Hi guys! Car is 99.9 percent done now. Have a problem with clutch disengagement. Not enough slave cylinder movement to disengage. I built a fixture to invert (right side up) the slave. I am 100 percent sure there is no air in the system! This car originally had a vw diesel engine, and may not have the "kit" master. I dont know. Anyone know the right willwood part number? Maybe it just needs rebuilding/replacing. Any ideas?

[GoDadGo]

What transmission are you running?
Mendiola, Porsche, Etc?

[beeman]

I have an extra kit master cylinder if you need one, but I don't know if that would fix your problem

[oldchevyguy]

What transmission are you running?
Mendiola, Porsche, Etc?

It's a Porsche 996- 01.

[tanderson1]

I was 100% sure that i had all the air out of my system too, I had the same problem. Someone on this forumn told me i must have air in there, they were right. I bled it again for the 4th time this time i used a c-clamp to hold the slave all the way in while i bled. I also moved the slave higher while bleading. Sure enough that did the trick.

I also had a g96-01 from a 996.

[GoDadGo]

It's a Porsche 996- 01.

Could you possibly call a Porsche Dealership to see if they could give you the specs for the clutch master cylinder?

https://www.pelicanparts.com/More_In...RoCH_kQAvD_BwE

Maybe the issue is the size of the master if you are 100% sure that all the air is out of the line and that you have no leaks in the system.

Good Luck!

[NAZ]

Most of the leading clutch makers can provide you with the distance the T/O has to travel for full engagement. Or you could determine that yourself -- just a bit harder. You could then calculate the volume needed to operate the clutch with your current slave cylinder and that will give you the volume your M/C needs to displace. Volume is a simpe calculation -- if you can calculate the displacement of a single cylinder engine you can calculate the volume of a M/C or slave cyl. That way you are using science not by guess and by golly to determine your needs. And if it comes out that what you have should be working then you know you have a problem with the system -- air entrapment, short stroke, etc.

And don't forget to bake into that calculation the T/O arm ratio -- you need to determine the slave cyl stroke necessary to achieve the T/O bearing travel for full release.

[tanderson1]

for your trans you need the wilwood master and the Porsche slave. Not the slave that came with the kit.

[oldchevyguy]

I have a willwood clutch master cylinder. I dont know what size bore it is. I cant read the side if it without taking it off. When I purchased the Porsche transaxle kit it came with the correct Porsche slave cylinder.
I really am sure there is not air in the system. I tilted the slave in a jig I made so that the bleeder screw was on top and tilted higher than the rest of the body.
So either the master is bypassing, or it's not the right size for the slave.
Any body running a 96-01? Did you use the kit supplied master cylinder?

[VRaptor SpeedWorks, LLC]

Here are all of the part numbers for all of the Wilwood MC's available. The kit comes with 3/4" MC's for both the brakes and clutch. You can easily see what size MC you have without taking it off....it's cast right into the side of the MC under the reservoir....easily seen as you can see from the photo.

Does you clutch pedal feel really solid or does it feel spongy?

20190705_084907.jpg

20190705_085253.jpg

[oldchevyguy]

Here are all of the part numbers for all of the Wilwood MC's available. The kit comes with 3/4" MC's for both the brakes and clutch. You can easily see what size MC you have without taking it off....it's cast right into the side of the MC under the reservoir....easily seen as you can see from the photo.

Does you clutch pedal feel really solid or does it feel spongy?

20190705_084907.jpg

20190705_085253.jpg

Peddle has very little freeplay, and no musheyness.

[oldchevyguy]

Ok, so I stood on my head, and looked from the other side, and i saw the 3/4 cast on the master cylinder housing. So it's got the "stock" mc size. Maybe its worn out. Talked to FFR tech, and he said they do wear out. Or, maybe my set (96-01 needs the next size up?

Can anyone using a g96-01 transaxle tell me what clutch master cylinder they are using? In other words, the one that can in the kit, or another one??? Thanks

[jamesfr58]

I have the G96-01 Transaxle and IU use the clutch slave cylinder listed below. It works and will engage and disengage, peddle is stiff after power bleeding. I found the best price on Ebay as Porsche parts are expensive from parts dealer. Hope this helps,

https://www.ebay.com/itm/Premium-Clu...item21543024da

Brand: Centric Parts
Part Number: 138.37003
Item Condition: New
Item Description: Clutch Slave Cylinder
Manufacturer Brand Description: Premium Clutch Slave Cylinder-Preferred
Quantity Needed: 1;
Item Specifics:
UPC: 805890630401
Application Summary - 2000: 1999 - 2008 Porsche 911, 2005 - 2005 Porsche Boxster

This part generally fits Porsche vehicles and includes models such as 911, Boxster with the trims of Carrera 4 Convertible 2-Door, Carrera 4 Coupe 2-Door, Carrera 4S Convertible 2-Door, Carrera 4S Coupe 2-Door, Carrera Convertible 2-Door, Carrera Coupe 2-Door, Carrera S Convertible 2-Door, Carrera S Coupe 2-Door, S Convertible 2-Door, Targa 4 Convertible 2-Door, Targa 4 Coupe 2-Door, Targa Convertible 2-Door, Targa Coupe 2-Door . The engine types may include 3.2L 3179CC H6 GAS DOHC Naturally Aspirated, 3.4L 3400CC H6 GAS DOHC Naturally Aspirated, 3.6L 3596CC 219Cu. In. H6 GAS DOHC Naturally Aspirated, 3.6L 3596CC H6 GAS DOHC Naturally Aspirated, 3.8L 3824CC H6 GAS DOHC Naturally Aspirated. This part fits vehicles made in the following years 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008.

[oldchevyguy]

I have the G96-01 Transaxle and IU use the clutch slave cylinder listed below. It works and will engage and disengage, peddle is stiff after power bleeding. I found the best price on Ebay as Porsche parts are expensive from parts dealer. Hope this helps,

https://www.ebay.com/itm/Premium-Clu...item21543024da

Brand: Centric Parts
Part Number: 138.37003
Item Condition: New
Item Description: Clutch Slave Cylinder
Manufacturer Brand Description: Premium Clutch Slave Cylinder-Preferred
Quantity Needed: 1;
Item Specifics:
UPC: 805890630401
Application Summary - 2000: 1999 - 2008 Porsche 911, 2005 - 2005 Porsche Boxster

This part generally fits Porsche vehicles and includes models such as 911, Boxster with the trims of Carrera 4 Convertible 2-Door, Carrera 4 Coupe 2-Door, Carrera 4S Convertible 2-Door, Carrera 4S Coupe 2-Door, Carrera Convertible 2-Door, Carrera Coupe 2-Door, Carrera S Convertible 2-Door, Carrera S Coupe 2-Door, S Convertible 2-Door, Targa 4 Convertible 2-Door, Targa 4 Coupe 2-Door, Targa Convertible 2-Door, Targa Coupe 2-Door . The engine types may include 3.2L 3179CC H6 GAS DOHC Naturally Aspirated, 3.4L 3400CC H6 GAS DOHC Naturally Aspirated, 3.6L 3596CC 219Cu. In. H6 GAS DOHC Naturally Aspirated, 3.6L 3596CC H6 GAS DOHC Naturally Aspirated, 3.8L 3824CC H6 GAS DOHC Naturally Aspirated. This part fits vehicles made in the following years 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008.

Thanks. I already have that slave cylinder. The question is what are you using for the MASTER CYLINDER?

[GoDadGo]

What about just going up one size or maybe two?

Attached are two links for Wilwood's remote master cylinders:

https://www.wilwood.com/MasterCylind...ter%20Cylinder

https://www.wilwood.com/MasterCylind...Banjo%20Outlet

[oldchevyguy]

What about just going up one size or maybe two?

Attached are two links for Wilwood's remote master cylinders:

https://www.wilwood.com/MasterCylind...ter%20Cylinder

https://www.wilwood.com/MasterCylind...Banjo%20Outlet

I've thought about that. I've got 3/4 bore now. I could go to 7/8. Just wonder what everyone else is doing with the G96-01.?

[beeman]

The larger the master diameter, the more work you will be doing with your left foot. I have the same transmission with the OEM Porsche slave but dropped down to a 5/8 Toyota master cylinder with the goal of less pedal effort. But I haven't proved it works yet, which is why I haven't chimed in yet.
Have you ruled out clutch release fork, throw-out bearing, etc? Usually there is plenty of throw which requires a clutch stop to prevent overthrow

[oldchevyguy]

Anyone else have G96-01? What master cylinder are you using?

[jgtm]

I recently purchased a GTM with a very stiff clutch with Mendeola trans-axle. Turns out it had a 7/8 slave and a 13/16 master cylinder. After researching all this the master cylinder should be 1/8 inch smaller than your slave cylinder (industry standard). I replaced with a 3/4 inch master and it reduced the pedal effort I'm guessing 30 some percent. Still stiff but the clutch has springs for a 700 ft pound rating and will always be stiff. Sounds like you have the correct master and slave (22.2mm = 7/8) if they are both working correctly. You might try adjusting the pedal height for more travel with the master cylinder also.

[oldchevyguy]

Ok, so problem solved. I ordered a 13/16 " master cylinder [wilwood]. Removed the old one, which for a big guy like me is no small task. The old one had the threaded shaft shortened about 1 inch. Thinking this was wrong I installed the new one full lenght. Wrong! The pedal was way to high. So removed again and cut off the one inch. Reinstalled. Works perfectly now. I little stiff, like a early muscle car. Dont know why I had to shorten the rod. Has Wilwood pedal assembly. Anyway , It works!!!