DIY - Swap clutch slave cylinder and hydraulic line for improved feel and control

[muffinz]

Originally Posted by Legend@wheels

As it looks like it has no cons at all - im going for it!!
2 q's-

1 -The big diff is by changing the cylinder alone,right?
Changing the hydraulic line and/or removing spring is just an extra?
2 after doing that where is the most safe position(to make sure no damage will occur in the long run) for the pedal? 1:1 with the brake pedal height is ok?

1. Yes, the cylinder will change the feel. The line will change the performance under extreme conditions.

2. Yes 1:1 with brake should be fine. Just make sure you bleed it fully and that when you're stopped in gear the clutch doesn't grab until you let the pedal out a little bit. You don't want the clutch rubbing when the pedal is to the floor.

[Legend@wheels]

Originally Posted by muffinz

1. Yes, the cylinder will change the feel. The line will change the performance under extreme conditions.



2. Yes 1:1 with brake should be fine. Just make sure you bleed it fully and that when you're stopped in gear the clutch doesn't grab until you let the pedal out a little bit. You don't want the clutch rubbing when the pedal is to the floor.

Hi
1 Didnt understand what u said after 'Should be fine.'
2 how so?(the new line performance)what ill feel?
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[N234]

Originally Posted by Legend@wheels

Hi
1 Didnt understand what u said after 'Should be fine.'
2 how so?(the new line performance)what ill feel?
Sent from my SM-G960F using Tapatalk

1. When the clutch pedal is pressed all the way down, there should be no touching of the plates. While pressed all the way down, shifting gear should be easy, and on a flat surface the car should not roll when going from R to 1 to R).


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[Ultramaroon]

Originally Posted by Legend@wheels

2 how so?(the new line performance)what ill feel?

You won't feel any difference at all. Don't bother.

[biggie]

Hi,

I want to do the exact opposite, I need the clutch pedal to be softer (easier to press). I know this sounds like blasphemy, but don't pick up the stones just yet
I have spine surgery that bothers me when using the clutch in the GT86. I also have a Mazda3 that is much softer and I have no issues with that.

Don't get me wrong, I like the feel of the clutch pedal in GT86 as it is, because is gives much more feedback compared to the Mazda, I just need to make it softer because of the reason mentioned above!

Can anyone help me find the right slave cylinder for this?

P.S. I tried to find a stiffer spring to replace the OEM but with no success (I have LHD)

[tobin]

Originally Posted by biggie

Hi,

I want to do the exact opposite, I need the clutch pedal to be softer (easier to press). I know this sounds like blasphemy, but don't pick up the stones just yet
I have spine surgery that bothers me when using the clutch in the GT86. I also have a Mazda3 that is much softer and I have no issues with that.

Don't get me wrong, I like the feel of the clutch pedal in GT86 as it is, because is gives much more feedback compared to the Mazda, I just need to make it softer because of the reason mentioned above!

Can anyone help me find the right slave cylinder for this?

P.S. I tried to find a stiffer spring to replace the OEM but with no success (I have LHD)

Just curious, did you buy your car new? If not, did you check to make sure a previous owner hasn't already removed the spring?

[biggie]

The spring is there

[Sgtfluffy16]

this might be a dumb question. Is there any benefits to upgrading to DOT4 fluid? I know it has a higher boiling point. But can i use that in the clutch fluid resivior? I have to bleed the brakes on my R1 and that requires DOT 4 so i figure. 2 birds, 1 stone right?

[Ultramaroon]

Originally Posted by biggie

Can anyone help me find the right slave cylinder for this?

It would need to have a larger bore than stock 13/16 inch, 21 mm or greater. Depending on your motivation/resourcefulness, the fork could also be extended and the stock slave mounted on spacers.

I don't know about other parts that might fit. This mod was an accidental miracle for me.

Originally Posted by Sgtfluffy16

this might be a dumb question. Is there any benefits to upgrading to DOT4 fluid? I know it has a higher boiling point. But can i use that in the clutch fluid resivior? I have to bleed the brakes on my R1 and that requires DOT 4 so i figure. 2 birds, 1 stone right?

Totally fine to use DOT 4. No worries.

[Ultramaroon]

I regret losing the perch for my assist spring but not enough to scrounge up a replacement. I like the assist spring mostly because it seats the pedal firmly against the top of its travel. Other clutch pedals have a small torsion spring for pedal return. Manufacturers would love to ditch that spring but it's too expensive to make a linkage that doesn't rattle. From a design standpoint, the assist spring is an ingenious little way to make a feature out of an otherwise necessary evil.

Clevis joints are inherently sloppy but they're cheap. So much so that the addition of a return spring to manage tolerance is still cheaper than any other solution. I imagine the moment when a smart guy said "If we have to have a return spring, let's also make it push down on the pedal while we're using it."

On the production line, it's relatively easy (cheap) to adequately adjust a linkage that has a little slop. One of the unintended consequences of removing the return spring is that it requires adopting a whole new approach to adjustment of the pedal linkage. We have to actively manage that slop. On one side we have a rattling pedal. On the other we have a rattling master cylinder. I'll get into the latter later.

The first requirement of clutch pedal adjustment is that the master cylinder must be allowed to eject the plunger all the way to the stop shim. This is best for the life of the system because chassis noise/vibration is not vibrating the piston. It also guarantees full opening of the equalizing port for self adjustment.

Secondly, because we no longer have the return spring to pull the pedal home, we must carefully use the rubber foot as the adjustable hard stop for the pedal itself. The factory adjustment procedure allows for some clearance between foot and switch base.

I've found the sweet spot to be when the pedal is at rest, the cruise cancel switch is adjusted so there is almost zero clearance between the switch and foot. Set it to minimize the distance between lifting the pedal away from the clevis pin to where the foot comes into contact with the switch body.

I've driven one with an mtec spring. It's nice because it functions well for pedal return, and is less obtrusive. I'd use it If I really hated the assist spring. If I wasn't missing other parts, I'd have long ago reinstalled the stock one.

[EAGLE5]

When are you coming to the bay area again? I gotta install this but i need your help, dood.

[Ultramaroon]

Originally Posted by jsimon7777

When are you coming to the bay area again? I gotta install this but i need your help, dood.

I promise that I'll let you know before the next time I go down to visit my brother. Let's set up a drive afterward and make a fun day of it.

[Tcoat]

Originally Posted by Ultramaroon

I promise that I'll let you know before the next time I go down to visit my brother. Let's set up a drive afterward and make a fun day of it.

A "fun" day with J? You are optimistic.

[stockysnail]

I went back to the OEM slave as I broke my left foot (3 middle metatarsals) and got a stronger ACT clutch. Glad I went back as the new clutch with OEM slave is just as hard to push as the OEM clutch with smaller slave!