Upgraded Clutch Squeak

[Ultramaroon]

Man, excellent photos. We'll get back to that.


Your main issue is common. You have air in the system. You've described the symptom perfectly. If you already know how to bleed the system, just go for it. If not, we'll take the time to explain it.


The jiggle in your bearings is normal. I'd almost be willing to bet that your old TOB (the first one you jiggle in your video) is still actually serviceable. Of course use the brand new one but for the sake of understanding how it functions, the only thing that matters is whether or not it makes any noise while spinning loaded.

Say, for instance, you stuck it in a vice and set a brake rotor on top of it like a turntable. If you gently spun the rotor and heard even the slightest bit of white noise, it's done.

[Rybot]

Originally Posted by Ultramaroon

Man, excellent photos. We'll get back to that.


Your main issue is common. You have air in the system. You've described the symptom perfectly. If you already know how to bleed the system, just go for it. If not, we'll take the time to explain it.


The jiggle in your bearings is normal. I'd almost be willing to bet that your old TOB (the first one you jiggle in your video) is still actually serviceable. Of course use the brand new one but for the sake of understanding how it functions, the only thing that matters is whether or not it makes any noise while spinning loaded.

Say, for instance, you stuck it in a vice and set a brake rotor on top of it like a turntable. If you gently spun the rotor and heard even the slightest bit of white noise, it's done.

So air in the clutch system causes a limp pedal at high RPM? How?

Also, I assume it's just over time that air will get into the system?

As for bleeding, small tube on the bleed valve with a jar and depress until no more air bubbles, right? Should I take the opportunity to upgrade to DOT4?

At this point, I'm really not sure it it was the TOB or fork that was making the noise. Maybe it was both and I just managed to stumble across the fork issue at the same time.

I'm quite glad I finally tore it apart again and got it fixed. There's definitely a level of confidence I feel with regards to dissembling things now. Though, this platform is quite easy to deal with, as I'm now seeing.

I'm guessing you're right about the OEM TOB being serviceable, but it's not like it's going back in the car ever again. We'll have to see how long until this current TOB holds out.

Thanks again, and I'd at least like to know your thoughts on bleeding; furthermore, why air in the system causes high rpm limpi-ness like that.

[Ultramaroon]

Originally Posted by Rybot

So air is the clutch system causes a limp pedal at high RPM? How?

Ugh, no. I didn't read closely enough. Hell, I missed most of it. Long day of driving, impressed with photos, video... forgive me.

First thought after a SECOND quick read was that it was some sort of vibration kicking back the tob. Then by the third read I got to the bottom where I see you came to the same conclusion.

I'm going to just throw this back to clear the air, and then I'm going to read again, carefully, and think about it.

[Drakiv]

Originally Posted by Rybot

Alrighty!

Got the lion's share of my clutch issues fixed, but stay tuned for a REALLY weird followup problem I'm now having.

So, I got the TOB replaced. Pictures are as follows.


Here's the nastiness I created by not regreasing the pivot area when I first installed the aftermarket clutch and TOB. I doused the bell housing in brake clean and didn't think to hit the pivot with some love afterwards, so I think this may be why there's rusty dust on both ends.


More nastiness.

Fork nastiness.

Fuzzy nastiness.

All cleaned up.

All reassembled AFTER A GOOD AMOUNT OF REGREASING.

As for the actual TOB, here's a video. Note: I'm an idiot and filmed vertically, furthermore, I hadn't tried the other TOBs before making the video, so I thought the one in there wasn't too bad. BOY was I wrong.

.

So my effort was not in vain in the least. All squeaking is GONE. FINALLY.

BUUUUUT, I now have an intriguing problem with clutch engagement at high RPM.

I'll try my best to explain it.
Around 5k RPM, my clutch pedal becomes limper where I can tap it with my foot and it'll feel like the pressure plate isn't even pushing back, like very little taps will put the pedal almost to the floor like nothing is impeding it. Higher RPM and the pedal limp-ness increases to where, at close to redline, I have to completely floor the pedal to disengage the clutch to shift.

Once I let the RPMs decrease to about 4.5k and lower, the pedal firmness returns slowly, not all at once, and the catch point returns to normal (about 9/10 travel towards driver, very high).

I was gently feathering the clutch pedal to feel the catch point, and it really does float back once the RPMs lower past 4.5k.

I can hold the RPMs at a certain level and the catch point floats down and stays at a certain point. Higher RPMs and the catch point floats lower again and holds there.

Anybody have a clue what might be going on here?

I have a bunch of drivetrain stiffening mods that might be affecting a few things, but with the transmission assembly bolted to the damned engine, I wouldn't think that'd be affecting my catch location like this.

I don't think I need to bleed the system, as this condition doesn't happen under 4.5k, and it's not spongy or anything.

Is the clutch slave/secondary acting up and not giving me full actuation at high RPMs for some reason? Only thing I can think of is vibration at those RPMs causing the clutch slave shaft from fully touching the fork, otherwise, a clutch slave not functioning at high RPMs doesn't make a ton of sense to me as it's a hydraulic system, not really computer/RPM controlled.

Any ideas?

I got everything else fixed, but now I'm afraid I've got another mess on my hands.

@Ultramaroon and @humfrz , Help me 86 Shinobi. You're my only hope.

Have you ever adjusted your clutch grab point? It's a unique situation but it almost sounds like the pressure plate is being over centralized. Could be a possible adjustment is needed, maybe @Ultramaroon could chime in on this possibility. I am no clutch expert, just offering something I had read a while back on a ford forum.

[Ultramaroon]

https://www.bimmerforums.com/forum/s...l-after-5k-rpm

https://forum.miata.net/vb/showthread.php?t=507918

https://forums.nasioc.com/forums/sho....php?t=2088183


This seems to be a thing that, until tonight, I've never heard of. I also call bullshit on all the theories about leaky slave and air.

I think it's kickback but I don't know why.

I suggest having a friend rev it for you while you actually have hands on the fork. If it's kicking back you WILL be able to:

1. With the engine off, simulate it and get a feel for how much it's kicking back by just squeezing the fork by hand.

2. Measure it by being clever with a caliper.

3. Reproduce it by revving the engine in neutral at a standstill.


This is brand new to me. I can only tell you what I would try. All of your previous observations are spot on. I was an idiot for skimming over it.

[Ultramaroon]

Originally Posted by Drakiv

Have you ever adjusted your clutch grab point? It's a unique situation but it almost sounds like the pressure plate is being over centralized. Could be a possible adjustment is needed, maybe @Ultramaroon could chime in on this possibility. I am no clutch expert, just offering something I had read a while back on a ford forum.

Only 2 critical factors in play for pedal position.

1. Needs to clear the relief valve for self adjustment. (check)
2. Needs to fully disengage the clutch (check)

But I feel ya. I'm baffled.

[humfrz]

After doing a brief literature search ...... it appears that this is not an unusual situation ..... and without a definite fix. Some of the more popular attempts are to:

* completely flush the hydraulic clutch system and replace the fluid

* adjust the clutch

* replace the master and slave cylinders and lines

* replace the pressure plate because, it has weak fingers

Question: You mentioned you replaced the clutch ..... did you replace the pressure plate also .. ??

My first hand clutch experience was only when engines wouldn't go over 4000 rpms (not more that once at least .....), so. I'm not much help.

If you're sure that their isn't air in the system or it's not gummed up ..... I wouldn't worry about it...... just push the clutch all the way to the floor when shifting at higher rpms.


humfrz

[Rybot]

Alright. After not enough sleep, let's get back into this.

Originally Posted by Ultramaroon

https://www.bimmerforums.com/forum/s...l-after-5k-rpm

https://forum.miata.net/vb/showthread.php?t=507918

https://forums.nasioc.com/forums/sho....php?t=2088183


This seems to be a thing that, until tonight, I've never heard of. I also call bullshit on all the theories about leaky slave and air.

I think it's kickback but I don't know why.

I suggest having a friend rev it for you while you actually have hands on the fork. If it's kicking back you WILL be able to:

1. With the engine off, simulate it and get a feel for how much it's kicking back by just squeezing the fork by hand.

2. Measure it by being clever with a caliper.

3. Reproduce it by revving the engine in neutral at a standstill.


This is brand new to me. I can only tell you what I would try. All of your previous observations are spot on. I was an idiot for skimming over it.

Ok. Glad I get to be a guinea pig for @Ultramaroon's knowledge base. I also find this very interesting from a mechanical standpoint.

That being said, how, or WHAT, is happening under there that's causing the engagement point to change through the pedal?

Mechanically speaking we've got the flywheel>clutch disk>pressure plate>TOB>fork all connected via input shaft. High rpms in gear, the entire assembly is spinning at that rpm. The only separate assembly is the fork and TOB. The only thing that would change the catch position is the displacement of the TOB to the pressure plate, so somewhere along the lines they are getting separated at higher rpm, possibly. I don't know...

Oh boy, not enough coffee yet.

Is high rpm vibration causing the retaining spring behind the fork to not push the TOB against the pressure plate tines?

As to your points:
1) With the engine off, I think the problem won't exist as at idle, the catch location is where it should be. I'll try it though.

2) Am I to measure the travel the top edge of the fork has, or how much space I can create if I pull the fork into the slave shaft thereby creating a void between the TOB and PP?

3) I'll definitely need to try revving it since your links say it should be reproduce-able given neutral revs.

Originally Posted by humfrz

After doing a brief literature search ...... it appears that this is not an unusual situation ..... and without a definite fix. Some of the more popular attempts are to:

* completely flush the hydraulic clutch system and replace the fluid

* adjust the clutch

* replace the master and slave cylinders and lines

* replace the pressure plate because, it has weak fingers

Question: You mentioned you replaced the clutch ..... did you replace the pressure plate also .. ??

My first hand clutch experience was only when engines wouldn't go over 4000 rpms (not more that once at least .....), so. I'm not much help.

If you're sure that their isn't air in the system or it's not gummed up ..... I wouldn't worry about it...... just push the clutch all the way to the floor when shifting at higher rpms.


humfrz

@humfrz, I replaced the entire clutch assembly. Flywheel (with pilot bearing), clutch disk, pressure plate, and TOB.

While I'm sure parts can be defective and go bad (my last TOB after <year), I don't wanna go changing out master/slave cylinders just yet. I do want to see if adjusting the clutch pedal downwards any makes the catch point unreachable since my current point is so high in the travel.

I will likely still bleed the system, as it probably needs it after 2.5 years, just to make sure.

While I know the workaround is just dealing with a "shifty" clutch pedal and flooring it to shift, I prefer not having that kinda chaos/problem if I'm ever in an autocross/track position. Added complexity with shifting and floating catch points isn't something I want to deal with when driving fast or for autosports. That's just asking for an unsettling "clutch kick" drift to happen, which, while fun, wouldn't be ideal for most situations.

I will call my clutch manufacturer to see if they can provide any insight, as I'm sure someone there has heard or seen of this at some point, but I suppose we'll just have to wait and see.

Thanks for all the info, guys.

Sorry this has turned into a hypothetical rant as to the mechanics of a clutch system and my inexperience.

I do hope I can at least help whomever happens across this problem next by getting it figured out.

[Rybot]

@Ultramaroon

Reading through some of those posts you linked again.

The bimmerforums one. I absolutely don't believe over-torquing a pressure plate would cause this. It shouldn't be moving axially, only spinning with the flywheel, so I call bullshit on that.

The miata one provides some interesting insight. Not sure why the PP tines/fingers would "give out" at high rpm. They're just flat springs that are spinning. I can't imagine the centripetal force they see would cause them to buckle or weaken at higher rpm.

The nasioc one just details the problem, but I'm glad I'm not the only one having it.

[humfrz]

Originally Posted by Rybot

Alright. After not enough sleep, let's get back into this.



I will likely still bleed the system, as it probably needs it after 2.5 years, just to make sure.

.

Yep, good plan.

Just not bleed the system but flush it with new fluid.

That may not fix the situation, but is sure as heck won't hurt anything ....


humfrz

[Rybot]

Originally Posted by humfrz

Yep, good plan.

Just not bleed the system but flush it with new fluid.

That may not fix the situation, but is sure as heck won't hurt anything ....


humfrz

So, turkey baster on the reservoir, new fluid in, gravity bleed, or is getting help from a friend to pump the clutch easier?

[humfrz]

Originally Posted by Rybot

So, turkey baster on the reservoir, new fluid in, gravity bleed, or is getting help from a friend to pump the clutch easier?

I'd suggest you get a friend to pump the clutch (with the outlet hose submerged in a jar with fluid) while you keep adding fluid......


humfrz

[wheelhaus]

Originally Posted by Rybot

So, turkey baster on the reservoir, new fluid in, gravity bleed, or is getting help from a friend to pump the clutch easier?

I found using a friend helped a lot with this one... The clutch pedal needs the hydraulic pressure from the clutch spring to push the pedal back up. Cracking open the bleeder relieves this pressure and the clutch goes back to a relaxed state, so the pedal stays on the floor. First time I did this process it took a hot minute to figure out what was happening, because the pedal didn't do what I expected...

So, I hooked it up like a normal brake caliper bleed, and the order of operations was:
helper pressurizes the line (pedal down).
open slave bleeder.
close slave bleeder.
helper raises the pedal with their toe.
check master reservoir level.
repeat.

Once the pedal is picked back up, the master cylinder will suck down some fluid from the reservoir.

[Rybot]

Originally Posted by humfrz

I'd suggest you get a friend to pump the clutch (with the outlet hose submerged in a jar with fluid) while you keep adding fluid......


humfrz

What size tubing should I grab? 3/8ths? Also, so I can kill two birds with one stone, does that size also happen to work with the brake calipers?

Originally Posted by wheelhaus

I found using a friend helped a lot with this one... The clutch pedal needs the hydraulic pressure from the clutch spring to push the pedal back up. Cracking open the bleeder relieves this pressure and the clutch goes back to a relaxed state, so the pedal stays on the floor. First time I did this process it took a hot minute to figure out what was happening, because the pedal didn't do what I expected...

So, I hooked it up like a normal brake caliper bleed, and the order of operations was:
helper pressurizes the line (pedal down).
open slave bleeder.
close slave bleeder.
helper raises the pedal with their toe.
check master reservoir level.
repeat.

Once the pedal is picked back up, the master cylinder will suck down some fluid from the reservoir.

Perfect. Thanks. Once I get some new fluid, I'll get to work on that. Nothing that 10 minutes can't solve, right?