Clutch Fluid

[Ohio Enthusiast]

Originally Posted by ZDan

Figure over time I'm effectively refreshing the fluid without actually having to bleed the clutch...

Unless you're sucking the line dry I doubt it will refresh the fluid that actually does the work in the line. I see no reason for the fluid in the reservoir to mix in with the fluid in the line, but I'll be happy to learn otherwise.

[ZDan]

Originally Posted by Ohio Enthusiast

Unless you're sucking the line dry I doubt it will refresh the fluid that actually does the work in the line. I see no reason for the fluid in the reservoir to mix in with the fluid in the line, but I'll be happy to learn otherwise.

Every time you hit the clutch pedal, fluid from the reservoir goes into the line. Car gets regularly shaken at the track so fluid going into the line ever is a different volume of fluid every time. I would guess that over a much longer period of time over bumps on the street it gets further mixed. Ultimately, I would *bet* that between the interval over which I do this (1-2 years), the fluid gets migrated around *reasonably well enough*.

Anyway, I've only ever had clutch fluid "go bad" at the track once and that was in a 240Z that had possibly decades-old fluid in it.... Including extended usage of couple/few dozen track days and 200+k street miles over 11 years in the S2000, which I never fully bled the fluid, just did this reservoir-fluid replacement scheme...

[Ultramaroon]

Originally Posted by Ohio Enthusiast

Unless you're sucking the line dry I doubt it will refresh the fluid that actually does the work in the line. I see no reason for the fluid in the reservoir to mix in with the fluid in the line, but I'll be happy to learn otherwise.

Can also pull the fork forward to squeeze all the fluid into the reservoir. I can picture tying it there and using a syringe. Pretty cool idea but I'm also in the "Clutch fluid - Meh" camp.

[ermax]

Originally Posted by Ultramaroon

Can also pull the fork forward to squeeze all the fluid into the reservoir. I can picture tying it there and using a syringe. Pretty cool idea but I'm also in the "Clutch fluid - Meh" camp.

Yeah my attitude is I will have a master or slave go bad before the fluid is really an issue. It doesn't get cooked like the brakes do and if the clutch fails it's really not a major safety issue. But, fluid is cheap enough and the syringe is easy... can't hurt that's for sure. I drove my car last week without a clutch (bent the pivot even on an OEM setup) in rush hour for about 20 miles and 40mins. It was a bitch having to crank it at every stop but I managed.

[ls1ac]

I have some old cars and have found that the fluid being hydroscopic will absorb water and eventually start to corrode the steel and aluminum parts. I do change mine on the new cars but only because i am there on the lift doing the brakes and other things.

[Ultramaroon]

Originally Posted by ermax

Yeah my attitude is I will have a master or slave go bad before the fluid is really an issue. It doesn't get cooked like the brakes do and if the clutch fails it's really not a major safety issue. But, fluid is cheap enough and the syringe is easy... can't hurt that's for sure. I drove my car last week without a clutch (bent the pivot even on an OEM setup) in rush hour for about 20 miles and 40mins. It was a bitch having to crank it at every stop but I managed.

Crap. I'll bet the quill is all gouged up. Such a shitty design.

[ermax]

Originally Posted by Ultramaroon

Crap. I'll bet the quill is all gouged up. Such a shitty design.

When it first went I assumed it was the TOB that disintegrated so I proactively ordered a new TOB and the bearing cover which arrived Saturday morning. Once I dropped the tranny and saw it was the pivot I ended up ordering a new pivot and fork (although it looked okay) which a iced on Monday. I also snapped a stud on the over pipe and couldn’t get the remainder out so I ended up picking up a used over pipe. Oh and then when I was ready to put fluid back in it I realized I forgot i never went out to get some and it was too late to go out for some that night. Ugg. All total the car was out of commission from Friday until Wednesday night. But yeah the bearing cover had two very pronounced groves in it. Oh and the dust cover on the slave is ripped from the strange angle it was in when the fork shifted out of place. So I need to deal with that eventually too. It’s kind of sad the fork and pivot can’t handle the load of the OEM clutch. The tranny feels really nice now. I suspect it’s a combination of new fluid and the clutch fully disengaging now. The pedal is also feather light again.

[Ultramaroon]

Originally Posted by ermax

It’s kind of sad the fork and pivot can’t handle the load of the OEM clutch. The tranny feels really nice now. I suspect it’s a combination of new fluid and the clutch fully disengaging now. The pedal is also feather light again.

It's not the clutch, it's the sleeve in the TOB. The cylinder's height to diameter (aspect ratio) is too low. That makes it extra vulnerable to binding, which is why the pronounced grooves form and exacerbate the binding, which wears the grooves deeper and...

That plastic part could easily be molded so the contact cylinder extends a little further back behind the bearing-to-fork pivot axis, it would completely eliminate the issue.

[ermax]

Originally Posted by Ultramaroon

It's not the clutch, it's the sleeve in the TOB. The cylinder's height to diameter (aspect ratio) is too low. That makes it extra vulnerable to binding, which is why the pronounced grooves form and exacerbate the binding, which wears the grooves deeper and...

That plastic part could easily be molded so the contact cylinder extends a little further back behind the bearing-to-fork pivot axis, it would completely eliminate the issue.

Makes since and yeah there is a ton of room on that shaft where they could have extended the plastic inner race to give it a more stable base. It’s like they took a tranny from one platform and then looked in a random Subaru parts bin for some clutch components and said, yep that should do it.