Pull Type Clutch Master Cylinder, ...just when you thought there wasn't another way to do it! Options

[tomeric914]

You've probably seen my other threads on the hydraulic release bearing and reservoir mounting, but I've saved the best for last.

There are some decent solutions to adding a clutch master cylinder. Some require cutting a 2" diameter hole in the pedal cluster area which doesn't allow you to use the pan underneath and opens up a giant hole for water and air to come in, others are really expensive (using the G50 pedal assembly), and at least one other I've seen uses a cool bell crank mechanism which places the master cylinder inside the car by your feet.

My solution uses a pull type AP Racing master cylinder located inside the center tunnel. What's neat about it is that there is only one hole needed to be cut, there is no noticeable intrusion into the cabin (carpet or center console will cover it) and it is completely reversible if someone wanted to convert back to the stock clutch cable arrangement.



The master cylinder is pulled by the stock clutch arm which has about 1.1" of travel which is perfect for AP master cylinder.



There were lots of little design challenges in this project which required some late night searches on the web for alternative parts. Placing it inside the tunnel and working around a roll cage made for some installation challenges as well.



(Sorry for the blurry image) This was taken upside down through a mirror inside the tunnel which was reversed so it shows in the proper perspective. Yes, the throttle cable runs right by the master cylinder but does not interfere with it. I haven't had a chance to test drive it yet. It's currently 1 deg F and we have about 3' of snow.

These master cylinders aren't inexpensive, but the rest of the parts aren't terrible. If anyone is interested in doing this conversion, I'd be glad to put a kit together! (IMG:style_emoticons/default/driving.gif)

Thanks to:

@cupomeat for putting the idea in my head and allowing me to bounce ideas off him
@gregamy for the "pretirement" encouragement
@tygaboy for mentioning SendCutSend in his many well put together videos

[Ninja]

Good stuff, thanks for posting.

I will be using a complete Boxster/Cayman 6 speed.

The clutch master is a mod I am going to have to do.

Sticking it in the tunnel is an excellent option!

[tygaboy]

I accept full responsibility for helping enable your cool ideas!
Now contact SendCutSend and tell them they should sponsor me! (IMG:style_emoticons/default/lol-2.gif)

[barefoot]

Very clever work, good stuff !! (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif)

Barefoot

[Ninja]

Got me thinking about this...

I'll add some type of weep hole/tray for failure diagnosis.

I hate master cylinders in the foot well. Lots of Italian cars have this feature, especially for clutch masters.

In failure they leak into the carpet/on your feet. Makes a freaking mess and will eat up the paint.

In the tunnel you might not have noticeable leakage until the clutch hydraulics fail.

So, long term brake fluid inside a section of the car that is VERY hard to clean up properly.

Just a thought, it's still a great place to mount this puppy!

[tomeric914]

In the tunnel you might not have noticeable leakage until the clutch hydraulics fail.

Yea, I try to do everything I can to build it right, but at the same time I fully expect it to fail. There is drainage in there.

[Cupomeat]

Tom, You always go to such great lengths to do these things right. I am always impressed. This is just another amazing improvement to the basic canvas the 914 is.

You've probably seen my other threads on the hydraulic release bearing and reservoir mounting, but I've saved the best for last.

There are some decent solutions to adding a clutch master cylinder. Some require cutting a 2" diameter hole in the pedal cluster area which doesn't allow you to use the pan underneath and opens up a giant hole for water and air to come in, others are really expensive (using the G50 pedal assembly), and at least one other I've seen uses a cool bell crank mechanism which places the master cylinder inside the car by your feet.

My solution uses a pull type AP Racing master cylinder located inside the center tunnel. What's neat about it is that there is only one hole needed to be cut, there is no noticeable intrusion into the cabin (carpet or center console will cover it) and it is completely reversible if someone wanted to convert back to the stock clutch cable arrangement.



The master cylinder is pulled by the stock clutch arm which has about 1.1" of travel which is perfect for AP master cylinder.



There were lots of little design challenges in this project which required some late night searches on the web for alternative parts. Placing it inside the tunnel and working around a roll cage made for some installation challenges as well.



(Sorry for the blurry image) This was taken upside down through a mirror inside the tunnel which was reversed so it shows in the proper perspective. Yes, the throttle cable runs right by the master cylinder but does not interfere with it. I haven't had a chance to test drive it yet. It's currently 1 deg F and we have about 3' of snow.

These master cylinders aren't inexpensive, but the rest of the parts aren't terrible. If anyone is interested in doing this conversion, I'd be glad to put a kit together! (IMG:style_emoticons/default/driving.gif)

Thanks to:

@cupomeat for putting the idea in my head and allowing me to bounce ideas off him
@gregamy for the "pretirement" encouragement
@tygaboy for mentioning SendCutSend in his many well put together videos

[Cupomeat]

Tom, You always go to such great lengths to do these things right. I am always impressed. This is just another amazing improvement to the basic canvas the 914 is.

You've probably seen my other threads on the hydraulic release bearing and reservoir mounting, but I've saved the best for last.

There are some decent solutions to adding a clutch master cylinder. Some require cutting a 2" diameter hole in the pedal cluster area which doesn't allow you to use the pan underneath and opens up a giant hole for water and air to come in, others are really expensive (using the G50 pedal assembly), and at least one other I've seen uses a cool bell crank mechanism which places the master cylinder inside the car by your feet.

My solution uses a pull type AP Racing master cylinder located inside the center tunnel. What's neat about it is that there is only one hole needed to be cut, there is no noticeable intrusion into the cabin (carpet or center console will cover it) and it is completely reversible if someone wanted to convert back to the stock clutch cable arrangement.



The master cylinder is pulled by the stock clutch arm which has about 1.1" of travel which is perfect for AP master cylinder.



There were lots of little design challenges in this project which required some late night searches on the web for alternative parts. Placing it inside the tunnel and working around a roll cage made for some installation challenges as well.



(Sorry for the blurry image) This was taken upside down through a mirror inside the tunnel which was reversed so it shows in the proper perspective. Yes, the throttle cable runs right by the master cylinder but does not interfere with it. I haven't had a chance to test drive it yet. It's currently 1 deg F and we have about 3' of snow.

These master cylinders aren't inexpensive, but the rest of the parts aren't terrible. If anyone is interested in doing this conversion, I'd be glad to put a kit together! (IMG:style_emoticons/default/driving.gif)

Thanks to:

@cupomeat for putting the idea in my head and allowing me to bounce ideas off him
@gregamy for the "pretirement" encouragement
@tygaboy for mentioning SendCutSend in his many well put together videos

[live free & drive]

I have a couple of questions:

Are those PEM nuts and if so did Send Cut Send put those in?

Are you going to put a clevis end on the push-rod that directly attached to the clutch arm ear? or is there an offset requiring spacing between the ear and the pull shaft end?

It looks like there are two possible part numbers from AP Racing that would support this - which one did you use?

Would you be willing to post or sell your STL file that send cut send worked from?

[tomeric914]

Are those PEM nuts and if so did Send Cut Send put those in?

Yes, SCS installs many types of fasteners

Are you going to put a clevis end on the push-rod that directly attached to the clutch arm ear? or is there an offset requiring spacing between the ear and the pull shaft end?

Clevis or bolt will work

It looks like there are two possible part numbers from AP Racing that would support this - which one did you use?

All of the pull type MCs are the similar. The difference in part numbers is likely the trunnion bearing type.

Would you be willing to post or sell your STL file that send cut send worked from?

Hahaha, no. (IMG:style_emoticons/default/dry.gif)

I'll sell you a part if that is what you want, but I'm not giving away the hundreds of hours of labor that it took to get the geometry just right.

[Shivers]

Very cool.

[Cupomeat]

So, what I want to know now is how is it in operation? Do you see a definite difference?
Does it shave off at least 2 sec at WG?

(IMG:style_emoticons/default/WTF.gif)