[V8Vairs] Hydraulic Clutch Question-long

[Sadek Charles H DLVA]

Background-what I learned from Tilton on my Corvair GT3 car, #89 and some
things to look for.

Tilton said the MC and the slave should be the same diameter when using with
a mechanical arm (rather than a concentric hydraulic throwout bearing
mounted inside on the diff case ).  However, this makes the pedal very
heavy-takes three men and a gorilla to push the clutch pedal down.
Apparently, the MC to slave ratio is very critical. Some slave cylinders are
3/4" dia. While many are .8" dia or thereabouts. I am thinking of a slightly
smaller MC for my use, but the real solution is a hydraulic throwout
bearing.

You want your throwout bearing to rest just off-not touching-the clutch
fingers.  If it were hydraulic, they give 0.20 clearance.  (I presume you
are using a Corvair clutch diaphragm or similar-not a Tilton smaller assy.).
You need to determine if you have enough travel of your throwout bearing in
relation to the travel of the slave-the outer end of clutch (fork) arm. I
measured a 1.76 clutch fork ratio.  I do not know what amount of travel of
the throwout bearing is required for a stock fingered diaphragm.

Perhaps someone has a stock Corvair and can tell us what linear distance the
fork arm travels after contact with the fingers, for complete disengagement.

1. You need to look under the dash and see if anything is bending or flexing
when someone pushes clutch in.
2. Suggest you look at your MC for seepage-even if you bled the other end,
who knows.
3.  I would mark linkage between slave and clutch fork and measure how much
travel you get and see if it is doing what you want.
4. Look and see if clutch fork is way off of moving throwout bearing into
contact, thereby running out of travel of inner clutch fork. Too much
initial clearance.
5. Make sure fork is properly on ball stud and in groove of throwout
bearing.
6. Make sure for whichever throwout bearing you are using, it gives you
proper geometry. For example, a early longer throwout bearing might fit the
later diaphragm - I haven't measured it to see if there is enough room with
a bent finger diaphragm- and a shorter stud, which means less available
travel of clutch fork.

Good Luck. Pls tell us what you find.

Chuck S
BBRT

-----Original Message-----
From: Chris Wills [mailto:cjwills at msn.com] 
Sent: Tuesday, June 28, 2005 5:35 PM
To: v8vairs at corvair.org
Subject: RE: [V8Vairs] Hydraulic Clutch Question

Don,

Your slave cylinder may be too big in diameter, so that it doesn't move much

compared to the master cylinder.  What are the two cylinder diameters?

Chris Wills



>From: Don Stephens <don.losthorseranch at direcway.com>
>Reply-To: v8vairs at corvair.org
>To: V8 Corvair <v8vairs at corvair.org>
>Subject: [V8Vairs] Hydraulic Clutch Question
>Date: Tue, 28 Jun 2005 15:04:10 -0600
>
>I am trying to install a new hydraulic clutch in my rig and have run into a

>wall. The previous owner had the usual 60s something brake and clutch 
>master cylinder, but it was pulling away from the firewall. After looking 
>at the pictures of the Rick Norris car, I tried to follow his lead by 
>putting an '87 Jeep master on the  firewall opposite the dash outboard 
>clutch pivot brace.
>
>I measured the amount of movement of the clutch rod from rest and fully 
>depressed. I then worked out the swing of the clutch arm under the dash and

>made sure that I was using the full amount of movement. I have bled the 
>living hell out of the system, and am fairly sure there is no air in the 
>lines, and had my wife depress the clutch pedal while I watched the TO arm 
>at the bellhousing move. It moves, but only about 1/2 way through what I 
>THINK it should move. It does not disengage the clutch.
>
>Can anyone stop a suicide from happening here and suggest a way to 
>troubleshoot this?
>
>I've also noticed that the return spring at the bellhousing is pulling the 
>arm at an angle, and I'm thinking that this might have worn the input shaft

>sleeve, but I'm just guessing....
>
>Don


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