gc161968

Hi Guys . .

One of this winters projects is to replace the clutch in my 68. Since I am replacing it its getting an upgrade to a hydraulic clutch. I am looking for all tips and recommendations on which kit to buy. Not looking to do a lot of fab work making something work but its not out of the question. Looking more for a direct bolt on kit that has the hydraulic cylinder outside the bellhousing. Any pics would also be great!

Thanks
Chris

MelWff

here is a link but they use a hydraulic throwout bearing

http://forums.corvetteforum.com/c1-a...er-source.html

gc161968

Thanks . . whats the pros or cons of hyd bearing vs non hyd?

MelWff

Have you found one that bolts to the bell housing? If not you dont have a choice other than a hydraulic throwout bearing. Personally I dont see the point in doing the switch.

DUB

It all has to do with the "lag-time"..as I will put it.

I prefer factory clutch master cylinder and a slave cylinder set-ups if I go hydraulic...It seems to have a good reaction time to what I feel when I engage and disengage the pedal and the "lag-time" for "things" to react.

I do not like the aftermarket hydraulic throw-out bearing that I was supplied with some time ago. The aftermarket system I had installed seemed to be "sluggish" and not "crisply" responsive ..versus the factory linkage style. Once it got all ripped out and replaced with a factory linkage style set-up...the clutch was awesome and responsive. The customer could grab third gear..... when before ...that was not even possible with the hydraulic throw-out bearing set-up.

Stop and think it like this...if you go hydraulic. If when you apply pressure to your clutch pedal and it moves the valving in the master cylinder.....which pushes fluid in a line or hose to your hydraulic throw-out bearing. If the bearing reacts slowly to this action...then your clutch disc is actually SLIPPING on the flywheel and pressure plate that "little bit" EACH and EVERY time you press the clutch pedal down. And depending on what type of disc you have...this can be detrimental to the life of the clutch disc....and when you let your foot off the clutch...the fluid does not INSTANTLY go back into the reservoir....there is a "lag" to it....which is also causing the disc to "slip" that little bit when coming off the flywheel/pressure plate surfaces.


Other may have feedback that contradicts this...which is fine and I am glad that they have something that works past 5000 miles...but I experienced it first hand in the "aftermarket" stuff that was offered about 12 years ago. And this is why I wont do it again....even though I know GM uses hydraulic throw-out bearing in the C5+ Corvettes. I like the instant response of a mechanical linkage clutch.

DUB

Shark Racer

Hydraulic brakes seem to work OK.

I would not, however, go through the effort to replace one with the other. Make sure your mechanical setup is in like new condition and I doubt you'll see a difference. Hydraulic is *much* easier to route and binding is nowhere near the problem it would be with mechanical.

qwank

I have a hydraulic clutch in my '81 and love it

Amorget

What setup did you use?

vette427-sbc

When I still had my 4 speed I designed one using an external slave to actuate the fork. Slave and master from an 85 chevy 1ton pickup.
I had an aftermarket clutch that was a little heavier than stock and the force to move the fork eventually flexed the bracket and caused the seal in the slave to weep causing no pedal. I ripped it out and put the mechanical linkage back in. Similar pedal pressure in both systems. KISS

I have a t56 now with a hydraulic TOB that I like, but I did that because it was designed to use one.

Duane4238

I had a hydraulic clutch in a '72 MG Midget. I had to bleed it from time to time and add fluid to the master cylinder. Finally the clutch would not fully disengage and I had to replace the slave and master and the rusted lines. I prefer the mechanical linkage in my '72 Vette. If it's not working correctly, an adjustment is quite simple. Don't know why you'd want to put in a more complicated system to do the same job.
Duane

cv67

Ditto on that. Have a hys system now the linkage system is foolproof. Blow a seal on a slave (it will be when not if) and youre stranded.

Amorget

I am sorry, but that is not a valid reason to not go hydraulic. There is a reason why basically every modern manufacturer is using a hydraulic setup.

Shark Racer

It's one less thing for the engineers to have to worry about in packaging.

Amorget

Yes, that is one of many benefits of going hydraulic. Easier packaging, less maintenance and, less moving parts.

There is a whole lot more to go wrong with a mechanical setup as compared to a hydraulic setup. Same as there is a whole lot more to go wrong with a carb as compared to a fuel injection setup, or vacuum powered headlight motors compared to the electric motors, yet there are people who will argue that carbs and vacuum power pop up headlights are better.

Gale Banks 80'

Ok so I'm going to be one of the ones who " Contradicts " If one were to think that the fluid is slowing down the movement of the clutch it would be as simple as increasing the line sizes and fittings which would allow more flow. However I think that the engineers have all ready done this.
But to flip the coin, You are probably correct. Reading Dave Mcleain's book on the C3-C4 Corvette it is explained how the Engineers could control the Shock Load to the Drivetrain by using a Hyd Clutch for the then to be new Dana 44 C4. When the 1980 was about to be launched with the new Dana 44 one of the Engineers came in and realized that the C3 still had a Mechanical. So they decided that it was to late to do anything about it and they would just wait and see how many came back on warranty.
The aftermarket has no way of Engineering a shock load to a drivetrain that they don't have any control over, so it really doesn't apply to Us.

4SPDL81

I have a factory stock manly manual clutch in my '81....(that I like a lot)....Good Luck!

zwede

Back when I had a stock mechanical linkage I snapped the ball stud that holds the intermediate shaft to the engine block. I made it home, started in 1 st, got it into 2nd and rolled through a couple red lights and stop signs. Luckily it was late at night and no traffic.

My hydraulic setup has never done that.

I used factory parts: late 90's chevy pickup master, S10 slave. Kept the stock fork, connected it to the slave with a heim joint. Made my own bracket to hold the slave to the engine block & bellhousing.

427Hotrod

That's pretty slick Marcus! Got any pics of the master mounting? Did you reinforce the firewall any? How did it hook to the pedal? Ratio seem to work out OK? Any issues?

JIM

qwank

I used American Powertrian's system, but if I had to do it again I would go with Keisler because their bracket that mounts to the firewall is much nicer.

zwede

I don't have any pics. Hard to get a good angle. Mounting was simple. I drilled 2 holes for the bolts. The big hole was already there for the stock clutch rod. I had to trim off the corner for some bracket on the inside so it cleared (minor).

No, the McCleod RST clutch is so light that there is no firewall flex.

I cut the rod that came w/ the master and welded a threaded sleeve to it. At the other end of the sleeve I used a heim joint that hooks to the pedal. That gives me adjustability so the master has the piston in the right spot with the pedal up.

Ratio is good. Only issue I had was the fitting on the master to the reservoir was too close to the brake booster. I had to trim it to clear. I think it still touched or something because a few years later the fitting came loose from the master housing (it was just press fitted) and leaked. I super glued it back on and that has worked.