[DeTomaso] Clutch Master Cylinder and Shackle

Doug Braun doug at silicondesigns.com
Mon Jun 9 16:44:54 EDT 2008


	Yours sounds like the same CNC clutch master that I have.  Mine came
with the 90 degree fitting on the inlet as you described.  I had to cut off
the old metric bubble flare on the original hard line and form a new
US brake line double flare to fit the 90 degree fitting.  I can't tell about
the other items you mentioned while I'm here at work.  Let me know if you
me to look at it tonight?

	If you want to go back to original, you'll have to form a metric bubble
flare but the tool to do this was quite expensive the last time I checked.
Check with your local NAPA dealer or do a web search.  Maybe metric bubble
flaring tools are more reasonably priced now that Chinese manufactured tools
are so prevalent.

Doug Braun

-----Original Message-----
From: detomaso-bounces at realbig.com
[mailto:detomaso-bounces at realbig.com]On Behalf Of Daniel C Jones
Sent: Monday, June 09, 2008 9:18 AM
To: detomaso at realbig.com
Subject: [DeTomaso] Clutch Master Cylinder and Shackle

I had finished setting timing and installing the wide-band O2 last night and
wanted to take the Pantera for a drive to get some baseline air-fuel mixture
readings.  I'd made it to the interstate when the clutch got very stiff at
the top of it's travel (engaged, foot off the pedal).  I gave it a strong
and suddenly I had no pedal.  I was maybe 20 miles from home with a
bunch of lights and stop signs along the way.  30 years ago when I was
learning to drive, my dad had the foresight to not only teach me how to
drive a manual transmission but also how to shift without using clutch.
That came in handy last night.  I managed to make it home only once having
to start the car in gear at a light.  They've started to install walk/no
lights with timers that count down to when the lights change which was nice
for timing the lights.

When I got it home, I crawled under the dash and found out what went wrong.
The previous owner had installed a CNC clutch master.  It had a fair bit of
free play before any resistance was felt and I found out why.  It appears
the shackle was only threaded one or two turns (threading it all the way
down would have taken up the free play) and it stripped out.

Several questions:

 1. Is the CNC clutch master metric or SAE?  It appears the fitting on
    the hydraulic line was replaced so I wonder if that was to convert
    from metric to SAE and a second 90 degree fitting added.  If the fitting
    on the CNC is SAE, then is the stud also SAE?  Perhaps a thread
    mis-match was why the shackle was only retained by a thread?  If I
    re-flare the line to install an original clutch master, what fitting do
    I need and what is the flare angle?

 2. What is the thread size of the shackle (would be the same as the
    stud on the back of the original clutch master)?  I can thread a
    7x100 metric bolt several turns but the threads in the shackle
    appear more coarse.  Perhaps the previous owner ran an SAE tap
    through the shackle?

Getting the clevis back in looks like it's going to be treat.
Does anything keep the stud from rotating on the clutch master
(maybe just friction from the piston)?

Dan Jones

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