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

[JB86'd]

Is that even really MTEC in that thread? 1 post on this forum?

[Ultramaroon]

Originally Posted by ck-GT86

http://www.ft86club.com/forums/showthread.php?p=2234804

Tada! How true that is, i wouldnt know. I dont see a reason to remove the spring after swapping the slave cylinder to be honest. Best mod ive done to improve the feel.

I felt the same way. I'm a minimalist so when I first swapped out the slave I wanted to leave everything else alone. @Andrew025 convinced me to try it without the spring and I was even more pleased with the results.

In removing the spring I looked at the mechanism more closely and realized with a lowered/adjusted pedal, if the spring never gets over center, it continues to push the pedal downward.

For the auto-adjust feature of any hydraulic clutch to work, the master piston must be allowed to fully extend/relax. the hydraulic circuit between the master and slave cylinders is opened to the reservoir at the end of the piston travel. If it never opens, the free play is eventually taken up by normal clutch wear. Eventually it constantly rides on the throwout bearing.

At worst, if the pedal is adjusted so the hard stop (cruise cancel switch) prevents full master piston extension, the clutch begins to slip. I suspect this is your issue.

[JB86'd]

I feel pretty comfortable with the adjustments I've made. I lowered the pedal, removed spring, and replaced slave cylinder in that order.

Things I've verified:
1. When pressing the piston on the slave cylinder manually, the fluid in the resovoir rises.
2. My clutch pedal is a few mm higher than my brake pedal, and I left a small gap from the pedal assembly to the cruise control switch. In other words when you look at it you can see a tiny tiny bit of the white button, so I know the pedal is not being pushed down.
3. Clutch was bled after installing and there is no air in the system.
4. Put car in 1st, roll forward, stop, shift directly to reverse and roll backwards, no grinding or resistance.
@ck-GT86 Maybe verify the things listed above. @Ultramaroon Anything else required to verify safety of all those adjustments? I'm no expert.

[Ultramaroon]

Originally Posted by JB86'd

I feel pretty comfortable with the adjustments I've made. I lowered the pedal, removed spring, and replaced slave cylinder in that order.

Things I've verified:
1. When pressing the piston on the slave cylinder manually, the fluid in the resovoir rises.

Excellent. This is the most important and conclusive verification. Thank you very much.

Originally Posted by JB86'd

2. My clutch pedal is a few mm higher than my brake pedal, and I left a small gap from the pedal assembly to the cruise control switch. In other words when you look at it you can see a tiny tiny bit of the white button, so I know the pedal is not being pushed down.
3. Clutch was bled after installing and there is no air in the system.
4. Put car in 1st, roll forward, stop, shift directly to reverse and roll backwards, no grinding or resistance.
@ck-GT86 Maybe verify the things listed above. @Ultramaroon Anything else required to verify safety of all those adjustments? I'm no expert.

This is really good. One point entirely of personal preference:

I prefer having the rubber stop on the pedal resting against the switch body just enough so, while the piston is fully extended (easy to see) I can feel the free play in the clevis as I pull back on the pedal and compress the rubber stop.

If my foot slips off of the pedal, the shock at end of travel is not concentrated on the little retaining clip in the master cylinder. Not completely, at least. The whole assembly is as light as possible so it already has quite a bit of give. I'm probably overthinking it.

[ck-GT86]

Quick update, i installed the mtec clutch spring while at laguna seca. I say get it in addition to the slave cylinder, i love how the pedal feels now. You can feel the retraction of the spring.

[Ultramaroon]

@Jonesy86 and I just finished performing the final adjustment on his clutch. I have been driving mine without the assist spring so I took the opportunity to study his.

Observations:

1. The geometry of the mechanism is quite clever. The crest of the over-center is much wider than I remember. Then, deep into the arc, it rapidly decompresses. Picture a cam with a wide lobe and a steep profile. It is impossible to adjust the clutch so low the assist spring prevents the throwout bearing from disengaging.

Leave it in or remove it. Either way, it's perfectly safe and does not need to be considered when adjusting the clutch pedal height.


2. I... <ahem>.. think I like the spring. o.0

I didn't drive it enough to be sure so I'm going to reinstall mine.

[Andrew025]

I just ordered one of the MTEC springs to see if I'm missing out on anything.

[Ultramaroon]

Originally Posted by Andrew025

I just ordered one of the MTEC springs to see if I'm missing out on anything.

I'd like to check it out if that's cool with you.

[Andrew025]

Originally Posted by Ultramaroon

I'd like to check it out if that's cool with you.

For sure.
You'll get a chance to check out the SC as well.

[Ultramaroon]

Originally Posted by Andrew025

For sure.
You'll get a chance to check out the SC as well.

Playa. Holding them cards close to your chest. What flavor?

[Andrew025]

Originally Posted by Ultramaroon

Playa. Holding them cards close to your chest. What flavor?

JRSC

[ck-GT86]

Originally Posted by Andrew025

JRSC

So many praises for this, can you come to norcal?

[Andrew025]

Originally Posted by ck-GT86

So many praises for this, can you come to norcal?

CSG is probably closer to you

[Andrew025]

Today was not a good day to spend screwing around with the clutch spring.

Anyway, not sure how I feel about the mtec spring.
It's a lot lighter than no spring but gets rid of the slop.
It brings back a bit of the vagueness at the top of the release.
Only went for a quick drive so far but I'm gonna give it a week or so to test it.