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Thread: Possible to fit hydraulic clutch actuator on 915?

  1. #1

    Possible to fit hydraulic clutch actuator on 915?

    I'm wondering if it's possible to replace the cable clutch actuator on 915 with a hydraulic one from G50?

    Advice will be much appreciated. Thanks.

  2. #2
    Rick Cabell
    Impossible. The bell housing has no provision for the slave cylinder. That's only the beginning!

  3. #3


    Thanks Rick!

  4. #4
    Roland Kunz

    hydraulic clutch


    No way to fit the Porsche G50 unit but you can modify the lever and repostion it showing sideways then you can use a standard Tilton or Lucas actuator unit.

    Porsche use a similar idear on there 935.

    On my first 915 in 914 aproach I used the actuator to pull the cablestring


  5. #5

    hydraulic clutch

    I've been looking at Tilton's website, and is this what you're talking about? If so, what is the part number correct for 915?

    Cablestring? I thought hydraulics don't have cables?

  6. #6
    Roland Kunz



    Now telling old storys.

    My first 914/6 had a slight improved 2,7 and the clutch couldn´t hold the power so I used a 915 cltuch system and adoptet a 911 trany to the engine.

    This is the 911 2,2 trany with the pushed TOB lever.

    I picked a suitable Tildon clutch slave cylinder from a local car parts store ( Just waded trough there stock looking for suitable and affordable units ) and mountet tht unit admid to release the TOB lever via a long rod.

    When i swaped that engine to a 2,7 RS with Mahle sportkolben the 911 trany had a massive failure due the torque and my driving style so I adoptet a 915 trany.
    As money was short i used the previous tildon acctuatur but couldn´t make it like before.

    The solution was to use a old clutchcable, hang in the end to the lever and fix the other end to the trany.

    Now that wire made a big U. Inside the U i montet that acctuator with the 914 roll wheel so when I pressed the clutch the acctuator pulled the string to pull the oppesite way looking clutch arm.


  7. #7

    Re: hydr. never cease to amaze me! Your know-how, and your experiences blow me away. Please keep posting as health permits, and I hope all is going okay.

  8. #8

    Is there such a thing as magnesium cased G50 tranny?


    Thanks Roland for sharing your experiences with regard to hydraulic clutch actuators. As it sounded quite complicated, I'm wondering if there's such a thing as magnesium cased G50 transmission? As some of you may know, G50 is an all-round better transmission than 915 but in the interests of lightweight, magnesium casing would my preference, otherwise it would spoil the balance of the car. A G50 transmission at the same weight or even lighter than 915 would be magic in an early car, wouldn't it?

  9. #9
    Roland Kunz

    magnesium cased G50 tranny?


    The hydraulic actuator was needed to operate the 911 trany with the 915 clutch in the 914.
    I took the system over to the 915 trany as it had been allready installed.

    It isn´t complicatet, you just needed to fabricate most items.

    Most work was the pedal box.


    I never had seen a 950 or G50 with a mag case. Maybe Porsche was thinking about it.
    However the PDK gear housing cases used in the 956/962 where mag.

    The G50 trany is maybe a better trany over the previous 915/901 tranys but Porsche needed very long to make a standard syncromesh work good enough to perform like the Porsche synchromesh.

    Developemend from the 950/G50 startet in the mid 70´s when Porsche realized that the then new 928 was to heavy on the Porsche synchromesh system.
    Using a more enlarged version ( Porsche enlarged them from 901 over 915 to 930/928 ) wasn´t real practical as the wight and trany size went up and also the problems from even more inerta mass movment.

    Porsche then looked at the Borg Warner System again.
    The Problem with the BW system was it was heavy, slow and hadn´t a definate shift feel on HD applications.

    ZF and Getrag had the BW system in there tranys for High performance sportcars ( Ferrari, Iso, Aston, Maserati, De Tomaso, Jaguar ) but that was more a truck trany then a sportscar trany.
    Companys like Jaguar, Mercedes just skiped the manuals on the big engines, only offered automatics.

    Not a choice for Porsche so they "redesigned" the BW system calling it Vollkonus synchronisation ( full cone synchromesh ).

    The first cars to use that where the 928 followed by the 959. It was no doubt that the new car generations would have Vollkonus synchros. The new G50 trany generation for the 964 was finished.

    As the 930 still only had 4 speed Porsche adoptet the 911 body to the G50 trany and used the same layout for the normal 911 as well. Those are the 950 tranys.


  10. #10

    Hype about G50´s


    After hearing all the hype about G50´s, I´m now pleased with your information about G50´s.
    So I´m going to keep my 915 and fit Tilton actuator. I will keep you posted of the progress.

    Thanks again.

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