Hydraulic Clutch Conversion, 915 transmission/Bad knee Options

[GeorgeRud]

Are there any members that have converted their larger engined flat 6 or V8 conversion cars to a hydraulic clutch? I tried a search, but couldn't find too much information. My problem is a very bad left knee that is not getting better (at least until I get a knee replacement done), and a very stiff clutch pedal on my 915 gearbox. Mine is one of the early ones without the spring assist, so it is not easy to hold the clutch in without seeing stars!

Does the hydraulic conversion make the clutch effort any easier? My factory six has much lighter clutch actuation , but I need to do something to lighten the force needed to actuate the clutch in my conversion car. If someone has the correct bores and stokes needed for the hydraulic conversion (or perhaps the actual parts to use), that would be very helpful.

I'm hoping that someone has gone down this road and can give me some feedback! Thanks in advance for any advice.

[Bruce Hinds]

I had one of the early renegade V8 kits and the clutch was a bear. I put up with it for a long time and many years later Kennedy came out with a nice clutch package that my little wife could even work. It's Porsche unit.... my kit uses the 914 flywheel. The hydrolic package would be nice, but this would be pretty simple.

[brp986s]

The clutch on my 915 wevo is piece o' cake. I got a '75 911 pedal cluster and the omega contraption in back. Bit of a pita and a puzzle setting it up at first. The '75 and '76 911 pedal clusters have a spring that forces the clutch pedal down instead of up. I wonder why it wouldn't be possible to update your set up. On the other hand, I've heard of the early style 915 "long arm" wasn't that heavy either. Is it just your knee?

I've been told that you have to match front and back. Meaning, the throw of the pedal lever has to be matched with with whatever actuation was used on the gearbox. If you got it wrong your pedal travel will be short, but the effort high. You can get it wrong the other way such that the pedal travel is long and light, but the clutch may not disengage.

[GeorgeRud]

The pedal assembly I am using is the original '73 914 one, and the transmission is a '75 915, backdated to a 74 lever arm (the '75 one had the strange clutch cable that wrapped around the outer part of the arm to clear the crossover exhaust pipe of the '75 911. I may have to see if there is a difference in the pedal cluster from the 914 and 911 of those years.

It does shift fine, so there is no problem engaging or disengaging the clutch other than the effort required.

[ClayPerrine]

Contact Rich Johnson (a914guy@aol.com). He has been selling kits for hydraulic clutch conversions for years. Has one on his 3.0L. The same kit is installed on Richard Fisher's Brodix v-8 powered 914.

[mipstien]

Anyone got a kit for a stock 914? Would be kinda nice although this cable clutch is the closest I've felt to a hydraulic before

[turboman808]

No ones ever mentioned it, maybe because it's alot of money. Wevo makes a real nice hydraulic clutch conversion.

Probably get this myself some day.

http://www.wevo.com/Products/ClutchProduct...s-Superlite.htm

[Katmanken]

Not sure why your pedal is too stiff. I have a thought.

One is you might have a diaphragm type heavy duty clutch for whatever large engine you are running. Had a LUK 200mm diaphragm clutch in my Ghia and it was a bear. Couldn't make it slip but it was so hard to push that it ate a clutch cable a year, and broke three clutch pedals. But, it handled all the power from the monster engine and when it engaged, it laid rubber in two gears without any slip.

If you have a stiff diaphragm clutch like the LUK, you can get a softer pedal by keeping the clutch and going with a smaller clutch master cylinder or a larger diameter slave cylinder. The force applied to the pedal will be less, BUT the tradeoff is the pedal travel must increase. It's work in = work out where work is force times distance and the equation must balance.

So, your solutions are a new softer clutch that is easier to deflect (ie requires less work to actuate) OR keep the clutch and use a smaller piston in the front clutch master cylinder or a larger slave cylinder to produce the necessary work with less force/ longer pedal travel.

That's it for alternate choices.

Hope that helps.

Ken

[PRS914-6]

You can see my hydraulic clutch conversion HERE

A hydraulic system makes very little difference in effort. You gain some improvement from the reduction of friction, not hydraulics. It does make it significantly smoother. The reason is that to get easier you have to use a smaller master cylinder with a larger slave. That won't work. You need the same amount of movement as the cable provided and that means close to 1:1 MC:Slave. Bottom line, don't expect a big reduction in effort.

[IronHillRestorations]

I wonder if you can just use the anular hydraulic throw out bearing/slave, with the set up like Paul's?

[Larry.Hubby]

This thread talks about some of the hydraulic conversions people have done, including mine:

http://www.914world.com/bbs2/index.php?sho...c=90342&hl=

I have a 3.0 six with a 915 transmission in my car, but it's a '78 engine and trans, so I do have the over-center helper spring on the throwout mechanism at the transmission, and I added the helper spring down at the pedals as well to stay as close to stock as possible. The mechanical advantage can't be increased beyond stock without shortening the travel of the throwout lever, so I doubt you will get much relief from doing that before you run into inadequate clutch travel.

[ArtechnikA]

No ones ever mentioned it, maybe because it's alot of money. Wevo makes a real nice hydraulic clutch conversion.
http://www.wevo.com/Products/ClutchProduct...s-Superlite.htm

One reason is that the 5" Tilton clutches are race clutches and don't like slipping. This is fine for a race car but a PITA for a street car... I'd consider this myself if they ever made street-friction clutch disks...

[turboman808]

No ones ever mentioned it, maybe because it's alot of money. Wevo makes a real nice hydraulic clutch conversion.
http://www.wevo.com/Products/ClutchProduct...s-Superlite.htm

One reason is that the 5" Tilton clutches are race clutches and don't like slipping. This is fine for a race car but a PITA for a street car... I'd consider this myself if they ever made street-friction clutch disks...

Seems like the only option that may make it easier to to press the clutch. I have to imagine the hydralic part could be bought alone and made to fit something.

(IMG:style_emoticons/default/confused24.gif)

[Don M]

found this image on a VW site, check it out

http://i453.photobucket.com/albums/qq253/4.../hydclutch2.jpg