[Ernest]

Bear with me on this, I see the SKY has a self adjusting clutch, okay, I understand clutches, having replaced a bunch when I wa asyoung and building hot rods, The old chevys & fords had manual clutches, crawl under, well you know the rest, and the hydraulic clutches had slave cylinders, which still required, you guest it, crawling under so can anyone explain to this old country boy, using shade tree mechanic words how this new fangled clutch operates? Thanks

 

[Mallard]

It's not a new design. Self-adjusting clutches have been used in Mustangs, Rangers, Corvettes, F-Body's, etc, etc. To you they would look no different except for three springs in the clutch cover plate. It adjusts for wear of the disc to give you the same pedal feel throughout the life of the part. They install the same as any other clutch.

 

[Ernest]

Are you talking about the 3 fingers on the pressure plate, as oppposed to the many many thin finger on a diaphram pressure plate? I think it was a little rusty on that, I wasa thinking of the clutch adjustment at the throw out bearing fork, I am a little rusty, been a while since I did this kinda thing, about 35 years, give or take. Thanks

 

[boots]

Went to howstuffworks.com (very good website) typed in hydraulic clutch and basically it seems the slave cylinder replaces the old clutch linkage and this is what works the fork.

 

[Mallard]

http://www.lukusa.com/products/index.phtml?page=sac

 

[Ernest]

Thanks for the info, I understand clutches, having blown ny share back in the early top mid sixties, I was wondering if thre was some new technology out, but I guess connecting the power to the wheels is still the same, except for far more advanced materials. I built and racedm a '55 Chevy then, built it from stock 6 to small block. Although I will not experience that sensation of raw hHP again, I look forward to the SKY roadster as a ticket back to when driving was fun, and the speed limit was 70, & of course 24cents a gallon premium leaded gas,

 

[WopOnTour]

Bear with me on this, I see the SKY has a self adjusting clutch, okay, I understand clutches, having replaced a bunch when I wa asyoung and building hot rods, The old chevys & fords had manual clutches, crawl under, well you know the rest, and the hydraulic clutches had slave cylinders, which still required, you guest it, crawling under so can anyone explain to this old country boy, using shade tree mechanic words how this new fangled clutch operates? Thanks

Ernest, on the "old school" clutches the linkage was adjustable so that when the disc wears, you could adjust the linkage to get correct "free pedal" before the clutch dis/engages.
On a hydraulic clutch this clearance is automagically maintained,as the piston in the hydraulic slave cylinder only returns as far as neccessary to eliminate drag on the release bearing.
Think of it as the same way disc brakes stay adjusted as the pads wear. It just makes up the neccessary travel distance with additional fluid maintained with in the caliper piston chamber (just like the clutch slave cylinder)

HTH

Regards
WopOnTour

 

[TexSon]

So instead of having to adjust the linkage with clutch wear, you add a bit more fluid to the clutch master cylinder. A plus, but I don't feel you get the same feedback from a hydraulic clutch as you through the linkage of the older clutches. I rarely burned the clutch on a vehicle with linkage, but do it quite regularly on a vehicle with a hydraulic clutch. Know a number of folks with the same problem. Maybe I am just getting old....

 

[Skip]

Don't add fluid till it goes way down that way you know how much wear you have. Or replace it when it first slips on an incline in high gear. Or replace after 60 burnouts. Or repace when 90000 miles. Or if rich when you are on the side of the road with onstar. Either or it will be a long time before the clutch is done. Skip....

 

[Mallard]

Ernest, on the "old school" clutches the linkage was adjustable so that when the disc wears, you could adjust the linkage to get correct "free pedal" before the clutch dis/engages.
On a hydraulic clutch this clearance is automagically maintained,as the piston in the hydraulic slave cylinder only returns as far as neccessary to eliminate drag on the release bearing.
Think of it as the same way disc brakes stay adjusted as the pads wear. It just makes up the neccessary travel distance with additional fluid maintained with in the caliper piston chamber (just like the clutch slave cylinder)

HTH

Regards
WopOnTour

On a self-adjusting clutch (SAC) the adjustment actually goes on in the clutch, it's not the release bearing compensating for a gap. The diaphragm spring actually adjusts to a lower position in order to compensate for wear of the disc and maintain pedal feel/loads.

 

[WopOnTour]

On a self-adjusting clutch (SAC) the adjustment actually goes on in the clutch, it's not the release bearing compensating for a gap. The diaphragm spring actually adjusts to a lower position in order to compensate for wear of the disc and maintain pedal feel/loads.

OK so when the diagram spring moves to a "lower" position , what changes the position of the release mechanism, relative to this new initial placement?
ADDITIONAL FLUID IN THE SLAVE CYLINDER!!
( Hence the reason why the fluid level will drop from the normal level as the clutch wears)
WopOnTour

 

[WopOnTour]

So instead of having to adjust the linkage with clutch wear, you add a bit more fluid to the clutch master cylinder. A plus, but I don't feel you get the same feedback from a hydraulic clutch as you through the linkage of the older clutches. I rarely burned the clutch on a vehicle with linkage, but do it quite regularly on a vehicle with a hydraulic clutch. Know a number of folks with the same problem. Maybe I am just getting old....

Almost, it's the SLAVE cylinder, (not the master)But I whole heartedly agree with you on the "lack of feel" point though.I think they may difficulty matching the master to slave cylinder input/output ratios, to a desireable engagment point in the pedal travel.
Regards
WopOnTour

 

[Mallard]

OK so when the diagram spring moves to a "lower" position , what changes the position of the release mechanism, relative to this new initial placement?
ADDITIONAL FLUID IN THE SLAVE CYLINDER!!
( Hence the reason why the fluid level will drop from the normal level as the clutch wears)
WopOnTour

Yes, but I'm just clarifying that the release bearing adjusting to the gap between the diaphragm spring is not what makes it a Self-Adjusting Clutch. The self-adjusting clutch is a patented design by LuK. (Look at the link I posted above)

 

[theirishgonzo]

when the clutch was relace in my twin turbo stealth at 190k it was sliping in seccond not first. and after the clutch was replaced it sucked for a wheek the relese was so fast you eather allmost stalled or launched

 

[LS2 MN6]

The Self Adjusting does what it says, it adjusts with no user intervention. why a clutch needs to adjust well you should know that already! Wear is the #1 reason obviously.