P-trans and hydraulic clutch - again....

[GS guy]

Hi guys, I did the searching and basically came up with no difinitive answer: How do you set up a 901 trans with a hydraulic slave cylinder? The clutch fork comes out the bottom - so does the slave cylinder hang below the CV joint? There was a pretty good thread where some verbal descriptions were laid out - but no pics. Some discussion about the typical CNC slave not having enough travel for the posche clutch assembly? Alex was going to post a tech article on the installation? Any help here is much appreciated!

Jeff

[Wally]

Hi Jeff,
I'am fitting a Saco hydraulic clutch to a 915 trans, not a 901. The archive probably showed Shads 923 (=915 type) install topics.
Not sure if my info is any good for your 901...

Greetings,
Walter

[GS guy]

Thanks for your reply Wally. Yes, the archive I was referring to was the one Shad detailed his 923 hydraulic install. From his description, it sounded almost identical to my 914 box - until he described somehow turning over the clutch actuator arm. I'm not sure whether he was talking about simply inverting it in place? Or somehow relocating it so that it actually exited the bellhousing in another location? Too bad he never posted any pics - I'm sure they would do a lot of explaining! On the 914, there is only one exit location for this actuator fork - it has to exit down on the lower portion of the bellhousing. The 914 used a pulley just aft of the lever to reverse the direction of the cable - sending it forward again. In my installation there's no room for the pulley and it's mount so I am looking twards a direct slave to actuator fork installation. Shad also mentioned shortening this fork to get more travel at the TO bearing, but again I don't think this would work on the 914 box as any shortening would place the outer end inside the bellhousing.

Looks like it's going to end up being a full custom installation - figure it out as I go.
Jeff

[GS guy]

Oh - forgot to ask Wally: Do you know the manufacturer of the SACO mastercylinder? I'm basically growing my own hyd. clutch set-up and after having looked at a lot of available MC's from various manufacturers, I can't find one that has all the features of the SACO part.

If you've got any pics of your 915 install I'd be interested in seeing them!
Thanks,
Jeff

[Wally]

Hi Jeff,
What Shad meant, I think, was tapping the actuator arm of the shaft (its splined) and refitting it 90 degrees. That method gives a lot of possibilities for installing the slave cylinder :-)

The manufacterer of the mc I believe is the same as the slave cylinder: CNC.
I know CNC is also a computerized machining method, but the company seems to be called like that also.

Since the trans is now in the car (Hurrey!) and I can engage all 5 gears and reverse, I will take a few pics soon.

Greetings,
Walter

[GS guy]

Thanks Wally, I'll have a look in my CNC catalog and see if I can find that mastercylinder listed.

If I understand this right, you're saying that the throwout bearing actuator arm can be "clocked" in a different position on the 915 trans bellhousing? Say if you're looking at it from the engine point of view, the actuator arm can be located from the 7:30 position up to - say the 10:30 position? There's another opening in the bellhousing for this? Maybe I'm just not seeing this from my 914 trans perspective. Unlike the VW trans (which uses a throwout shaft which connects to the bellhousing in two locations at either end of the shaft), the 914 trans uses a forked arm or rod if you will, that pivots on a ball-ended stud that is mounted near the mainshaft in the bellhousing. The actuator arm has a socket that rides on this ball, and that's where all the pivoting is done. Since there's no way to re-locate this ball, there's really no way to relocate the way the actuator arm is positioned in the bellhousing. I guess the 915 trans uses something more similar to the VW trans in terms of a throwout "shaft", with end-mounted actuator arm?

Jeff

[GS guy]

Ahhh, I see the difference now. I should have paid more attention to the pics in the gallery section! So the 915/923 box uses a shaft mounted clutch release arm, similar to the VW box - but sitting vertically in the P-box. Now what Shad said makes a lot more sense!
Unfortunately, now I see that I'm pretty much stuck with the 914 style actuator arm in the OEM position. Oh well, the slave cylinder will have to be mounted low, along side and below the CV joint on the passenger side as was the original pulley drive on the 914. Hmmm... this opens up several potential problems - the biggie being whether the slave has enough travel to fully disengage the clutch using the OEM actuator arm leverage ratio.

Jeff