So I received some parts Thursday and began my Quest for the "bolt on Hydraulic Clutch upgrade" for the 901 trans. I'm mocking up the slave cylinder mount and need a few of you to double check 2 things on your car for me. Looking at the pic below;

#1 - As it sits when you measure the distance between the clutch arm and the housing is it about 3/8"nominal?

#2 - What is the travel of your clutch cable when the pedal is fully depressed. You can use one of the nuts on the cable as a reference point. Again, nominal measurements are acceptable but keep 'em in the Park. TIA, Kent

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no pic

FYI, VW Type 411 and 412 HAD hydraulic clutches on the 4 speed model. Most cars shipped to the USA were automatics though. Get a hold of a Type 4 manual and see what information is there. Since they had the same type motor the bell housings should be close.

Thx, edited!

Don't forget about the r32 style slave/throw out bearing.might be lots simpler.

http://www.ecstuning.com/Volkswagen-R32_MK...ES12/ES1851810/

Yes the bell housing on the VW411/412 has the same diameter as on the 914 (but the gearbox is of a totally different design).
The slave cylinder on the 411/412 is mounted in a hole on top of the gearbox and pushes behind the clutch arm.

/Lars S

I want this to be a "bolt on" conversion that would eliminate pulling the trans, welding or any other fabrication. There are guys that their only issue is a clutch tube or they just want the upgrade but don't want to get involved with a tear down/rebuild.
Good to know though!
Still looking for some input on my original request.

Contact Rich Johnson (a914guy@aol.com). He sells a bolt on kit for a hydraulic clutch.

Vanagon has a hydraulic clutch (or at least my '81 does). Mentioned for ideas and options

Still looking for some input on my original request.

I'll get you accurate measurements tomorrow Kent. What is this nominal measurement BS anyways? This is a porache. All measurements must be within .000001 of correct.

The transmission hydraulic setup is as easy pull type slave cylinder bolted to the ring gear side plate with a simple adapter. The clutch master cylinder part of the setup is the complicated part that usually requires welding, so a bolt-on solution may be difficult to design. Keep us abreast of any updates.

Higher eduction does pay off. Ethan was able to answer my question on the first attempt!


Correctomundo Jorge, but the pull types are costly. I have one of those set up now and may have to go that route but it goes against the AAA Flaps (available at any Flaps) design criteria I have set for myself. If'n you break down 1000 miles from home you need to be able to get that part quickly. For that reason the second generation design will use a "push" style slave cylinder and the mount for future cable shift workings!
In the FWIW column, I already have the master cylinder end completed and working on a few 914's. No welding required!

#1 yes, while everyone's flywheel clutch face height and/or preffered adjustment, both of my cars are at 3/8".

#2 both cars when fully depressed have a throw of ~1.125" give or take some...

Good. That's what I measured. Thx

Slightly off your topic but what are you planning on doing for the hydraulic line? Seems like running that might be more difficult than the rest of the install for the DIY crowd. Are pull type slaves really that dear that trying to make a push style work is worth the hassle? You still end up with a linkage that gives just as many issues as the cable

The line he will probably use fits perfectly INSIDE the clutch tube. -3AN braided stainless.

Chris is correct, Edwin. Why a push style? I want you to be able to walk into any local FLAPS and purchase a replacement part. You can't walk in and out with an 11.5" pull style slave at one of those places. Kent

Also.....
pull ttype slAve cylinders are incredibly sensitive to alignment. Despite many of them having universal joints on the rod, more often than not, any misalignment or the pull rod will tear the seals in a about a month.

There is a very good reason why there aren't any (that I know of) OEM manufacturers that use a pull style slave cylinder for the clutch.

The set up I had was the first one to come out of Dallas, and as Clay mentioned it used a pull slave bolted to the side cover. It used a stock brake fluid reservoir for the clutch hydraulic fluid. It's a simple and easy to install option.

It required modifying the pedal area for the clutch master cylinder, running a hydraulic line through the clutch tube, and then changing some studs on the side of the trans to mount the slave cylinder bracket.

The two main issues I had was bleeding the system, so I made a pressure bleeder from a brake reservoir cap and a valve stem; and the other was heat on the slave cylinder from the stock 6'er heat exchangers. I wrapped the heat exchangers and the slave with thermo-tech header wrap, and as far as I know it all still works fine.

I think Nissan used a pull type (at least I found one in my searches) but it wouldn't work for this set up. Another issue with the pull type is the size of MC required. I like my current set up with the MC "tucked away". BTW, there is a "little" trick to getting them bled easily.
In the FWIW dep't; I ordered an array of fittings, bearings and SC last nite. Parts are 10 days out w/ Xmas shopping and we'll be in Sedona right after Xmas so it will be a few more weeks.

Quick update: I had hoped to have a working version of this by Dec 31 but I was short an AN fitting so looks like next week before I have afinished working product to show.
The pull type cylinder was a no brainer and a quick mod but I chose not to pursue this route because it compromises my "availability" philosophy. Why install a part that is a special order, non-stock item. That and it would require the use of the longer Willwood MC. On the + side, it would be cheaper to produce the pull style kits by about $80 but..........................
On the other hand the push style uses a Honda MC and a Subaru SC that are available at any local FLAPS. As soon as the AN fittings arrive I'll post a video of the working install.

UPS dropped off some AN fittings so I powered up Ver.1. I know of at least 2 more versions I will try since I've done a trial. First up will be a switch to non-self centering bearings. I noticed they allow for some orbital movement about the axis. I also want to try some sealed needle bearings in lieu of the oilite bushings currently installed. Notice the nasty burn on the back of my hand? That prompted me to buy a pair of leather welders gloves. http://youtu.be/23G3qKv10cw

Ouch, That had to hurt
Looks great, nice work !!!!!!!

Here's some pic's of a ver.2. I need to see if Ethan still wants to be my Guinea Pig or if I need to install it on my '76. It can provide up to 1.625" stroke if needed. Should only need 1.375" stroke. We'll see. The clevis fitting shown will be changed with an appropriate thin head bolt later and I may tinker with moving the SC in about 2.5" towards the Heim fitting but otherwise I don't see a change from what you see here. The extra length bolt that passes thru the SC's left bolt hole is for future use. The return spring is temporary as the pressure plate will be the big spring. Anyway, the mechanism moves smoothly and the MC requires very little force. Changes include widening the plate to space the bushings further apart for stability. The plate's shape changed from an "L" to a wide "V" to relo the SC attach point. Entirely improved the drag about the bushings when rotating while in use. If that makes any sense. I did another video but it's more of what you've already seen so I didn't bother with it.

This is the adapter plate. After removing the old pulley & bracket remove the four nuts/washers from the trans axle and this bolts back on with the same nuts/washers, except one. The one on the far right is an extension that screws on as well.

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After that it's just sliding on the arm and a few more nuts n washers. It also re-uses the rubber trununion. I've been told the metal trununion is different.

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Pretty cool, Kent. I may be interested in acquiring this set-up.

Do you think this will require extra maintenance? Looks like lots of joints for dirt to get in and wear things down. Might need cleaning and lubing periodically to keep functioning?

--DD

Sorry for the stupid question but:

Since the pedal end will have a mechanical "lever driven" mechanism already, why cant the slave cylinder pull/push directly on the clutch lever instead of going through that mechanism first?
Then you can do any mechanical drive-ratio conversion at the pedal end?

With the tilton or wilwood pedal assemblies, I would think you could adjust the travel/leverage at the pedal cluster end.

Next question: Would we want the "floor mount" master cylinder type of pedal, or the "hanging" style that would put the MC up behind the firewall by the brake fluid resivoir?

Damnit, I totally dropped the ball on this. Got busy with other stuff; sorry. Anywho Mark, good timing. Ethan is too busy between his apprenticeship and school so I'm looking for a new guinea pig. PM me and we'll get together. The only thing you'll need is a reservoir. The one I used in mock up leaks.


That is a good question Dave. The answer is I'm no sure . This is why I need a guinea pig. I believe that the oilite style may be more robust but the needle bearing style is so smoooooooth. I would like to see both units experience equal time trials for comparison purposes. Either style could use small felt washers on both ends to seal out debris. Maintenance intervals are unknown at this point but I'm looking for every 3 yr's or longer. FWIW, Lots of us are running Heim joints nowadays but how many of you (A&P's excluded) know that Heim joints (at least the decent ones) need to be greased when doing maintenance?


No such thing as a stupid question, Stu. However, I might be because I'm not sure I understand your question well enough to respond but I'll try. I do have a pull model but went with the push style for ease of "on the spot repairs". The pull style are readily available on the internet but not at your local FLAPS, However, the Honda master and Subaru slave cylinders are very common items. There will be no pedal adjustments nor will they be needed. I'll set that up on this end. Just use the adapter plate I make with your current 914 pedal cluster. I'll set up the travel on this end so you will not have to ever touch it. If I missed your point completely let me know.

Well, that's a silly place to put the clutch master cylinder. I'll never get my foot back there!

Kidding aside, the off-road crowd typically hoses down their Heims with WD40 daily or just lets them run until they break and then replaces them. May not be the right application for heims.

What about sealed ball joints? If you haven't already, check out http://www.midwestcontrol.com/. Decent quality stuff at decent prices.

Just put a G50 pedal assembly in and the front end is done. Porsche already did the work and salvage yards give these away on the cheap. Easy to modify in about 30 minutes.

OK, I'll PM you and include my phone # (in case you don't already have it)

I think I have a spare reservoir ...

Hmmm ...

I am getting interested in hydraulic clutch assemblies for my car. What is the current status of this project?

Steve Hurt

The best I've seen on e-bay's been $329, so could you do me a favor and keep an eye out, if you see another one like yours (cheap) let me know?

Thanks

I decided to keep my black car (the 'BB') and need to schedule a date to get this back on track

My "Dance Card" is finally clear, Mark. Wendy's Bday was Friday so pick a Saturday and if we don't finish for some reason just take my white 914 home and come back next week or the next day. Everything is boxed up and waiting to be installed.

Cool. I can always toss the little '50' in the trunk and ride it home for the evening ...

... if I can get it back from Dianne ...

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Sorry to the OP but i see no need for this conversion.....

So, what's your point?

How did this work out? Got any pics of the installation?

my point is what do you gain besides a lighter pedal

Nah, just take mine if you need. This Sat or next? I'm free either one. or call me!


The whole point is reliablilty. If you snap a cable in BFE or anywhere else you'd better have a spare cable or a AAA card. With this set up you can walk into any FLAPS and walk out with part in hand.


Won't know until Mark sobers up enough to drive over here. Those Check points have taken their toll on him.

that's an epic piece of hand crafted hardware! it just had to be red. i look forward to reading of your successful results

This is the style kit used on Perry's car and several others that were done by Wes Hildreth here in the Dallas area.

Simple....

This is a mock up but it displays the key elements
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The fluid can be supplied by separate reservoirs or "T-ed" from a single brake system.

The primary cylinder (928) requires a bracket to position it on the firewall.
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A lever will have to be made to attach to the primary cylinder's piston which is pretty straight forward.
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The fluid line simply goes back through the tunnel.

A bracket for the rear mounted slave is fabricated as well.
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I do like the simple set-up shown with the pull cylinder. It would be cheap enough to keep an extra slave cylinder as a spare if it would ever be needed.

The only modification I could think of would be to use a Heim joint where the slave cylinder is mounted on the transmission to allow for the small amount of movement when the clutch arm is moved.

Is there a kit available that has the prefabricated bracketry to install? I do like the idea of a hydraulic clutch as my conversion car's clutch pedal (running a 915) is extremely stiff and I do worry about tearing out the clutch tube as the car ages.

Since Kent was generous enough to do this on the 'BB', I'm not going to turn his offer down. We'll be doing this modification this coming Saturday and I'll be reporting the results as soon as possible.

Good timing too - driving around the past couple of weeks, noticing that it's time the clutch cable needed an adjustment anyway.

Once this system is vetted, I'll pull the cable out and run a hard line through the empty cable sleeve to be more permanent. If other slave options come up, it should be easy enough to upgrade, if that become necessary

Function and reliability. That's why new car manufacturers have all made the change. Are there ANY cable systems left? (I ask because I really don't know, but I'm not aware of any) I've had hydraulic clutches since a Saab in the 80's. I now have two Subaru transmissions in 914's that use hydraulic clutches, and maintenance is checking the fluid levels, just like brakes. They just work, don't need adjustment and pretty much don't break.

The pull type slave that pulls enough is higher than a Cats ass in a Dog fight. 7/8" pulls are cheap. Allso, which FLAPS store will you walk into for a replacement if' you break down in BFE? I'm open to suggestions but the parts must be readily available.

Do the newer Porsche's use a pull type slave, or do they still use a cable?

Also, modern clutch slave cylinders are forward sprung (on a push type at least), and require no periodic adjustment. I have this on my Audi transaxle on my LS1 conversion car.

Andys

I think 1986/87 930 would have been the last Porsche with a clutch cable.

Except for the 924. all the water cooled cars had hydraulic clutches from the beginning.
911 series cars moved to hydraulic with the G50 transmission

None of them ever used a "pull type" slave.

Jim