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I have my Pantera 2881vin now for about 4 months and learning constantly and using this forum which is very usefull BTW.

I swapped my leaking master clutch cylinder, for a new one which I got through a vendor in the Netherlands. I did not change the slave cylinder or anything else. I have a system without the effort reduction kit. After mounting the new master clutch cylinder and bleeding the system, it turned out that there was not enough throw on the slave cylinder or distance which it travelled after maximum depressing the pedal to fully disengage the clutch.

Which is strange because before the swap the clutch disengagement worked well. It looks like the new master cylinder is not suited/compatible to the slave cylinder currently mounted. There were limited options to adjust the clutch system, basically only the distance of the clevis on the master cylinder rod. Started out with the same setting as for the old MC. Varying did not result in resolving the issue. There was not means to adjust the distance of the rod on the slave cylinder. It is not like it should be when looking at the parts manual and discussions. It actually has no means to adjust free play and is mounted horizontally.

Clutch Slave Cylinder 3

Now looking at my setup I see that it is certainly not stock and therfor I am assessing my options. see pic.

One of the parameters which would help me is to know what is the actual throw or distance the slave cylinder travels when the clutch pedal is fully depressed. When manually (with a big lever!) checking the disengagement of the clutch, I measured it to be around 1,5 inch ( one and a half).

I also read about a long throw slave cylinder. I guess this slave cylinder has a longer throw/distance it travels after clutch pedal depressing.

Does anybody have these figures available for me for both the stock and/or longthrow clutch slave cylinder? And can anyone explain the purpose of the long throw slave cylinder for me? Any other tips or insights?

Thanks in advance,



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  • Clutch Slave Cylinder 3
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thanks for your quick reply Simon. The thing is that it has worked up till now in that set up. I do agree that returning to stock is better however, I have no stock set up parts available at the moment. Would be interested in procuring these.

bedankt Simon, wilde al contact met je opnemen na de link van Martin Wildeboer. Mee eens met je suggestie. Misschien heb jij nog wat liggen wat ik zou kunnen overnemen? Anders is het even kijken hoe ik nu eea ga oplossen. Ik stuur je een appje hierover met jouw welvinden. Gr.


I think you can solved the problem by adding v.s welding a distance holder , it's easy to produce .

It looks you already have a long trow CNC (bleu) cylinder.

the problem is that you now have to much free play .

when you look on Pantera place  you find a sample .

Ik heb geen watts app, of internet op mijn telefoon alleen thuis een computer

waar woon je ?



Last edited by simon

Hi Marlinjack,

Understand your response, there is no way to adjust the HEIM joint because it is not a HEIM joint. I was  very surprised to find out that it was simply the threaded end with the eye with no connection other than being kept in the slave cylinder by means of the return pressure in the concave rod. There is no bolt or thread into the slave cylinder or bolt connection to adjust. I guess the PO had to McGiver a clutch situation a some point in time and decided for this less optimal solution. Especially since there is no free play adjustment possible.

that is the reason why i would like to know what other Pantera owners know about the amount of travel. It looks like about  one inch and a half for clutch disengagement. When I have some numbers I can better weigh my options and more importantly have a better discussion with the guys who sold me the new MC when checking for an alternate slave cylinder.

reg. J.

The first thing that comes to mind is something that has previously happened to me and other owners. You replaced the master cylinder so it now has very tight seals and is delivering maximum flow and pressure. It is delivering this maximum flow and pressure to the old slave cylinder. Just as the master cylinder seals had failed and gotten weak with age (likely leaking internally), so will the slave cylinder seals. The previous weak master cylinder did not overpower the weak slave cylinder seals, but the new master cylinder may now be causing an internal bypass within the slave cylinder.

Second issue is the potential for unknowingly changing the pushrod length when you replaced the master cylinder. Minor differences between old and new master cylinders, and pushrods if they were also changed, can greatly affect the performance of the clutch hydraulic system.

The previous advice given is quite valid, the only definite thing at this point is your system needs some tender loving care.

Good luck,


I'll post this but I doubt if it helps anyone.

going through posts here and various list of info I found the following comments

An OEM Pantera Clutch Master Cylinder bore measured 0.7465 inches (18.96 mm) and had a max stroke 1.25 inches (31.74 mm)

Informed by John Beckman stroke was 1.125”

An OEM Pantera Clutch Slave Cylinder bore measured 1.000 inches (25.4 mm) and had a max stroke 1.625 inches (41.27 mm)

OEM slave cyl bore is 1".  Max stroke is 1.625".Long throw slave cyl bore is 0.75".  Max stroke is 1.125

now, I made some notes taking a hydrualic engineer approch to look at volumes and force transfers

OEM MC volume (0.75/2)^2 X 3.147 X 1.25 = 0.5532

OEM SC stroke 0.5532/(1.00/2)^2 X 3.147 = 0.703

LT SC stroke 0.5532/(0.75/2)^2 X 3.147 = 1.25

OEM MC volume (0.75/2)^2 X 3.147 X 1.125 = 0.498

OEM SC stroke 0.498/(1.00/2)^2 X 3.147 = 0.633

Force calculation

Pedal to Master cylinder 7:1

Master cylinder to slave 1.78:1 (ratio of areas)

Slave to TOB 1.38:1 (inverse of 0.725:1)

Therefore pedal to TOB 17.2:1

thus 10 pounds on clutch pedal gives 172 pounds at TOB

I;ll keep looking to see if I ever wrote something in lay terms


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  • mceclip0
Last edited by jfb05177

Independent of the McGyver situation, if it worked before and you did not remove the slave either a) the new master cylinder has a different bore than the one you removed or b) there is still air in the system. Pantera clutches can be hard to bleed and get all the air out of, a vacuum  or pressure bleeder can be a big help.

there is a wrong longer lever mounted , and it looks there is a redesign of the slave cylinder bracket .

the original lever is shorter and the bracket  into an angle .

the adjusting bolt what is missing keep the slave away from a long distance free play .

some aftermarket slaves has a spring inside to keep some pressure on the slave lever.( Maserati )

the free play must be only a few mm .

Have you check if the pushrod system under the dash is mounted on the right way ? it's common that this is wrong mounted after a master cylinder is replaced.

Julian, bleeding is not difficult  because the master is above the level of the slave, just open the bleeder on the slave and it bleeds themselves .


Oh , and remember , this Pantera came out of the States ,a lot of former US owners always chance good working original systems. Maybe they have trayed to get a softer pedal pressure to use a longer trow-out lever.

Thanks for all the input, that helped a lot. After "consulting" with Simon, I went back to the car and mechanically adjusted the free play between the lever and the slave cylinder by temporarily inserting a socket over the thread of the HEIM joint. Indeed then the clutch did fully disengage after depressing. So it is clear that the fix is to increase the space between the plunger of the SC and the lever to take away the free play. I am going to make the heim joint adjustable to do that job.

I still remain baffled why it did work before the MC swap but lets say that is water under the bridge. Once again, I appreciate everybody's input and thoughts.

Dus Simon , dat werkte inderdaad!


Joep, in your clutch what's important is the final result: the disengagement distance at the flywheel. You check this with a flat feeler gauge thru the ventilation/inspection hole in the top of the bellhousing. A helper holds the clutch pedal to the floor while you reach in between the friction disc and flywheel surface. A few Panteras will gauge at 0.040" (equals 0.020" on each side of the disc). Most will be less. Using a too-thick clutch disc will force massive adjustment of everything for barely enough clearance. Some combinations of parts simply will not fit. This is why DeTomaso hammer-flattened stock clutch disc marcels- for more clearance. Leaving out the steel engine plate between block & bellhousing will change clearances, too. The cast steel bellcrank lever on the bellhousing can be shifted by one spline for more clearance if needed but also changes disengagement distance a little due the altered operating angle to the slave.

0 .020" clearance (per side) at max pedal travel is barely enough to separate the drive components without too much drag on the ZF synchros, which are difficult and expensive to service. Syncho assemblies include the mating gears & integral synchro cones which is why they're so ridiculously expensive! There's usually 0.020" or more run-out tolerance in clutch components. So inspect every single part of the whole clutch system for slop due to wear, age and replace doubtful parts. The linkage is all steel-on-steel and was never lubricated- likely not even from the factory. The over-center linkage upgrade in mid-'72 reduces pedal effort and can be retrofitted but adds 5 or 6 more steel-to-steel pivots that also wear & produce slop! Some owners meticulously add bronze bushings & hardened pins everywhere to remove slop.

What Can Help

Pair a slightly smaller ID slave cylinder with a stock master (the basis for so-called long-throw slaves), or a slightly larger master with a stock slave changes the hydraulic leverage and thus the clutch movement. Some long throw slaves are corrosion-proof stainless steel. Not all parts labelled 'Stock' are identical.

There are oil holes in the bell housing at the ends of the pivot cross shaft. Inside are bronze bushings that would like some oil - maybe for the first time! Early Panteras and Mangustas have needle bearings in there- also seldom lubed.

Changing clutch designs from a stock 6-spring Long clutch to a Diaphragm (GM style) clutch vastly reduces pedal force needed and may increase the disengagement distance just due to parts not deflecting with the reduced effort needed. This pays for itself in ZF repairs not needed! Diaphragm clutches are in two styles: straight-release-finger and curved finger. The flat finger type ideally needs a rounded surface throwout bearing while the curved finger one uses a flat surface throwout bearing like our stock ones. Using a flat face bearing in a flat finger clutch can produce a 'step' feeling at the pedal but otherwise works OK.

Some throwout bearings are constant-contact types and do NOT need any free play, which increases disengagement travel. This is highly desirable but when you adjust such things, be aware linkage free play (if used) changes when the engine, bellhousing and ZF all heat up. In a test, my ZF went to 185+ F degrees on a 5 hr 100 mph avg run to Las Vegas across our sparsely patrolled desert.  There's more but thats enough for now.... Good luck.


an update of the situation. I found that my new master cylinder that I replaced  was also leaking, so I got a new exchange unit from my vendor who confirmed that the cups in the new MCs they have, had gone bad after some storage time.

I installed the new MC yesterday, bled the system by pedal pumping and it now works perfectly. The slave cylinder now also works fine with the new MC providing enough throw without an adapter (see pic) which I screwed on the heim joint. With the adaptor I could take away the free play by adjusting which was not necessary anymore after the new MC swap. So end conclusion: New MC was faulty, which learns me never to exclude new parts as the potential source of a problem.

Thanks to all for their advice and tips and

@jfb05177, your calculations helped and I can confirm that the stroke on the stock MC = 1,125 inch.

The throw at my slave cylinder is about 21mm

@joules: Indeed bleeding is an important element, turns out that when I used the pressure bleeder system (ronson) it didnot adequately bleed the system. The pumping by foot, albeit labor intensive, worked best for me.




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  • 20201115_105351: fully extended

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