Slaves

General discussion about cars. Looking to buy a new car? Have a great driving story? Post it here!
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Slaves

Post by ClutchFork »

So the big thing for the past 20 or 30 years is the concentric slave cylinder inside the transmission (around the input shaft). These can be a real pain as there is no adjustment and any time you have to monkey with it, you have to yank the tranny.

So I inspected several front drive manual cars and they all have external slave cylinders and a clutch fork. Why did they not go with the concentric slave on the front drivers? And thankfully they didn't. If one is stuck with front drive, they can at least say there is one logical feature besides the manual transmission, and that is the clutch fork.

I think much grief could be spared if slaves were all external. Yes I had major grief with the 2001 Ranger and have zero desire for another Ranger manual after that.

My 1984 F150 had the external slave and I changed out the clutch without having to bleed the system. Truck ran for years after that just fine and never needed any hydraulics work.
Last edited by ClutchFork on Sun Sep 12, 2021 1:20 pm, edited 1 time in total.
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
watkins
Master Standardshifter
Posts: 15880
Joined: Sun Jul 01, 2007 12:42 am
Cars: '08 Saab 9-5 Aero wagon
Location: Salem, MA

Re: Slaves

Post by watkins »

You know what sucks? JK Wrangler clutch fork squeak.

Concentric slaves save space and apply a more even pressure. They are, from a technical standpoint, the superior design. Considering a slave cylinder isn't really a regular fail point, service simplicity definitely takes a back seat. The only real drawback is that they often seem to have rather terrible bleed valve designs on newer cars. At least on the Italian garbage I deal with. Fix that, no problem.
Rope-Pusher
Master Standardshifter
Posts: 11607
Joined: Mon Mar 16, 2009 3:44 pm
Cars: '08 Jeep Liberty
Location: Greater Detroit Area

Re: Slaves

Post by Rope-Pusher »

watkins wrote: Wed Aug 25, 2021 8:29 am You know what sucks? JK Wrangler clutch fork squeak.

Concentric slaves save space .....
....and space IS the final frontier, no matter what Nissan says!

and concentric slaves are less likely to get battered / knocked out of place when you drive over a fallen tree branch.

The even pressure thang is good too, as well as they eliminate tolerances (fewer system components), cost (fewer components again) and and the geometric inefficiencies of a fork / release lever moving in an arc whilst trying to press the release bearing squarely against the fingers of the diaphragm spring in the clutch cover.

Yanno, even if you made them as two halves that bolt together around the input shaft quill, there still isn't room in the bellhousing to unbolt them and remove them until you separate the trans from the engine. There often isn't even enough space to swing a clutch fork!
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

Rope-Pusher wrote: Wed Aug 25, 2021 2:01 pm
Yanno, even if you made them as two halves that bolt together around the input shaft quill, there still isn't room in the bellhousing to unbolt them and remove them until you separate the trans from the engine. There often isn't even enough space to swing a clutch fork!
That were another question I had, can one convert a concentric to an external. Not really, unless want to get a different bell housing and shorten the drive shaft i guess, but not work for front drive,

But then what is driving the presence of clutch forks in front drive vehicles? there must be some engineering drawback to the internal concentric in that configgeration.

Fact is I am against slavery, so the cable actuated clutch in the 1992 Mustang is perfect.

So who named it a slave anyway. We didn't call wheel cylinders on the old drum brakes slaves.
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
Rope-Pusher
Master Standardshifter
Posts: 11607
Joined: Mon Mar 16, 2009 3:44 pm
Cars: '08 Jeep Liberty
Location: Greater Detroit Area

Re: Slaves

Post by Rope-Pusher »

ClutchFork wrote: Wed Aug 25, 2021 6:58 pm
Rope-Pusher wrote: Wed Aug 25, 2021 2:01 pm
Yanno, even if you made them as two halves that bolt together around the input shaft quill, there still isn't room in the bellhousing to unbolt them and remove them until you separate the trans from the engine. There often isn't even enough space to swing a clutch fork!
That were another question I had, can one convert a concentric to an external. Not really, unless want to get a different bell housing and shorten the drive shaft i guess, but not work for front drive,

But then what is driving the presence of clutch forks in front drive vehicles? there must be some engineering drawback to the internal concentric in that configgeration.

Fact is I am against slavery, so the cable actuated clutch in the 1992 Mustang is perfect.

So who named it a slave anyway. We didn't call wheel cylinders on the old drum brakes slaves.
Here is who named it "The Slave Cylinder":

Image

I don't know that there is a trend for FWD to use cable or external slave in their clutch release systems...except to say that Concentric slave cylinders are relatively new......and many inexpensive Amish vehicle have designs based in the 1980s, when cables were the norm and if they had slave cylinders they were external.
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

I don't know who that robot guy is but he looks kind of nasty. If he is from TV or the movies, well I have not tuned in to any of that since 1989 (does that make me Amish?).

But is looking for the reason of external slaves on FWD I found a conversion article from concentric to external. So there is still hope. In fact, they call it a slave cylinder upgrade:

https://www.motortrend.com/how-to/1602- ... r-upgrade/


Further, I discovered the pesky designers were part of the problem. This next article says, "...and closer fit to the transmission which increases flexibility in passenger compartment design."
https://10secondracing.com/pages/concen ... e-cylinder
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
IMBoring25
Moderator
Posts: 3418
Joined: Wed Jun 11, 2003 5:01 pm
Location: OK, USA

Re: Slaves

Post by IMBoring25 »

That's probably part of it, and it's not as much flexibility of design as it is flexibility of installation. The more compact and self-contained package is more likely to be able to be reused if you then wind up hanging it with a different engine or in a different vehicle. There likely isn't as much other stuff competing for that particular patch of space in a transverse installation.

Concentric is better on pretty well every metric except maintenance. Of course, both vehicles I've had that needed slaves, they were the first important failure in the clutch system, so it wasn't even a matter of, "Something else will fail first, be sure to change it while you're in there." On the other hand, they were also both WAY, WAY out of warranty, when the manufacturer really probably doesn't care too much either way.
Rope-Pusher
Master Standardshifter
Posts: 11607
Joined: Mon Mar 16, 2009 3:44 pm
Cars: '08 Jeep Liberty
Location: Greater Detroit Area

Re: Slaves

Post by Rope-Pusher »

ClutchFork wrote: Wed Aug 25, 2021 11:57 pm I don't know who that robot guy is but he looks kind of nasty. If he is from TV or the movies, well I have not tuned in to any of that since 1989 (does that make me Amish?).
You arent familiar with "THE MASTER CYLINDER!"?

https://felixthecat.fandom.com/wiki/Master_Cylinder
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

Rope-Pusher wrote: Thu Aug 26, 2021 8:11 pm
ClutchFork wrote: Wed Aug 25, 2021 11:57 pm I don't know who that robot guy is but he looks kind of nasty. If he is from TV or the movies, well I have not tuned in to any of that since 1989 (does that make me Amish?).
You arent familiar with "THE MASTER CYLINDER!"?

https://felixthecat.fandom.com/wiki/Master_Cylinder
Wow. I remember Felix the cat but not the Master Cylinder. I may have been in single digit age but there is a lot of way back stuff I don't remember. In fact, if I remember anything of Felix, it was the funny voice, and wasn't there an episode where a boy plugged a leaking dike with his finger to keep the town from flooding? Or maybe I got my cartoons mixed up. But as a small child I was glued to the television for the entire morning of Saturday cartoons and remember great disappointment when the cartoons were pre-empted by the funeral of an assassinated president.
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
Rope-Pusher
Master Standardshifter
Posts: 11607
Joined: Mon Mar 16, 2009 3:44 pm
Cars: '08 Jeep Liberty
Location: Greater Detroit Area

Re: Slaves

Post by Rope-Pusher »

ClutchFork wrote: Thu Aug 26, 2021 10:54 pm
Rope-Pusher wrote: Thu Aug 26, 2021 8:11 pm
ClutchFork wrote: Wed Aug 25, 2021 11:57 pm I don't know who that robot guy is but he looks kind of nasty. If he is from TV or the movies, well I have not tuned in to any of that since 1989 (does that make me Amish?).
You arent familiar with "THE MASTER CYLINDER!"?

https://felixthecat.fandom.com/wiki/Master_Cylinder
Wow. I remember Felix the cat but not the Master Cylinder. I may have been in single digit age but there is a lot of way back stuff I don't remember. In fact, if I remember anything of Felix, it was the funny voice, and wasn't there an episode where a boy plugged a leaking dike with his finger to keep the town from flooding? Or maybe I got my cartoons mixed up. But as a small child I was glued to the television for the entire morning of Saturday cartoons and remember great disappointment when the cartoons were pre-empted by the funeral of an assassinated president.
I'm imagining that some cartoonist was having brake system issues with his car and that's why he named Felix's arch-enemy "The Master Cylinder"

Could just as well been named "The Self Adjuster" if that had been the offending component.
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

Rope-Pusher wrote: Fri Aug 27, 2021 8:41 am Could just as well been named "The Self Adjuster" if that had been the offending component.
And had it been in the mid 1980s and the cartoonist had an F150, it could have been named "The Ignition Module."
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

Did anyone ever come up with an answer to this:

So I inspected several front drive manual cars and they all have external slave cylinders and a clutch fork. Why did they not go with the concentric slave on the front drivers?
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
Rope-Pusher
Master Standardshifter
Posts: 11607
Joined: Mon Mar 16, 2009 3:44 pm
Cars: '08 Jeep Liberty
Location: Greater Detroit Area

Re: Slaves

Post by Rope-Pusher »

ClutchFork wrote: Sun Sep 12, 2021 1:20 pm Did anyone ever come up with an answer to this:

So I inspected several front drive manual cars and they all have external slave cylinders and a clutch fork. Why did they not go with the concentric slave on the front drivers?
I kinda said something about it on the post with the Master Cylinder.....Not as much has ben redesigned on the FWD Amish transmissions...they are mostly just building what they've been building, in order to keep them inexpensive.
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
User avatar
ClutchFork
Master Standardshifter
Posts: 1935
Joined: Wed Mar 06, 2013 2:55 pm
Cars: 2008 Fusion 2.3L manual
Location: Detroit MI

Re: Slaves

Post by ClutchFork »

Rope-Pusher wrote: Sun Sep 12, 2021 3:59 pm
ClutchFork wrote: Sun Sep 12, 2021 1:20 pm Did anyone ever come up with an answer to this:

So I inspected several front drive manual cars and they all have external slave cylinders and a clutch fork. Why did they not go with the concentric slave on the front drivers?
I kinda said something about it on the post with the Master Cylinder.....Not as much has ben redesigned on the FWD Amish transmissions...they are mostly just building what they've been building, in order to keep them inexpensive.
Ah yes, now I see it. Well, another consideration, but one the manufacture typically does not seem concerned with, is the difficulty of changing the slave in a transverse engine/tranny. I don't know how easy it is to drop the tranny in a front driver, but I would think it is worse than a rear driver since the differential gear assembly must be packaged with the tranny. so probably have to remove one or both axle shafts before you can drop the tranny?

The external slave is visible from above and presumably can be reached from above in a number of front drivers.
Stick shiftin since '77
theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...
watkins
Master Standardshifter
Posts: 15880
Joined: Sun Jul 01, 2007 12:42 am
Cars: '08 Saab 9-5 Aero wagon
Location: Salem, MA

Re: Slaves

Post by watkins »

The ease of transmission removal is entirely dependent upon the vehicle and transmission in question. Neither are manuals, but an RT minivan with a 62TE is a hell of a lot faster to pull than a WK2 with an eight speed; even in the rare RWD configuration.
Post Reply