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Create a Custom Hydraulic Clutch System for
T-5 Upgrades: 65-66 Mustangs |
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As shown on my
previous webpage, I originally went from a Z-Bar setup to a Cable Clutch
system when converting to the T-5. There
was nothing wrong with the cable clutch, except that I was uncomfortable
with it’s proximity to the headers.
Even with wrapping the cable, it was still concerning. The cable was somewhat long, ran down
between the shoulders of the shock tower and then snaked it’s
way back through the headers. If you
have shorty headers or stock exhaust, then the
cable system is great. |
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I’d seen several other websites
where home designed hydraulic clutch systems were used. I tried to use their information as much
as possible. All of the current
systems are designed primarily around the CNC brand of parts. These sites
include: |
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These sites became the basis of how I researched and performed my clutch install. All these sites do a great job of explaining the basics of the system (M/C, Slave, hose), but still leave some of the design/fabrication issues to the builder. Hopefully I can shed some light on that part |
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Locating the Master Cylinder: I chose to do all the part locating off the car in a
mock up. I removed the pedal support, pedals, and the brake master cylinder. Then, on the bench, I bolted the pedal
assembly and M/C together with a spacer plate that duplicated the
firewall. It had the existing clutch
rod hole, Brake M/C hole, and pedal support hole
pattern. This was done to 1) duplicate the car and get the best angle on
the firewall for the clutch M/C and 2) find the proper alignment to drill
the new attach hole in the clutch pedal.
The off the shelf CNC 711 master cylinder comes with the mounting flange welded vertically. (The JMC kit uses a modified CNC master cylinder where the flange is relocated horizontally and the unit is canted.) The off the shelf unit has to be tilted approx 45 degrees in order to be centered in the existing clutch hole and still clear the mounting flange of the brake master cylinder. The photo (top right) shows a template made from the flange of the M/C. It is taped in position and used to drill the clutch M/C attach bolts. |
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Mounting the Master Cylinder: While on the bench during mockup, the shape of the internal anchor plate could be determined. Starting out in the shape of the clutch M/C mounting flange, it get’s oversized to provide a larger footprint. The plate needs to 1) cover an area as large as possible, 2) not hang over the edge of the firewall bumpout (serves no purpose), 3) keep from hitting the forward pedal support bracket, and 4) keep from hitting the steering column. I made 2 identical plates of 1/8” plate steel, then bolted the M/C to them on the inside of the firewall with 7/16” grade 8 bolts and locking washers. |
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Mounting M/C Push Rod to Pedal: Lower photo to right shows the attachment of the CNC M/C
pushrod to the existing clutch pedal.
Positioning is critical in order to get the maximum pedal throw and
keep the push rod as horizontal as possible. The end of the push rod required a
5/16-24 Heim joint (Ball Joint Rod End) in order to attach it to the pedal
using a 5/16” hex key bolt. Upon
alignment, the new hole in the clutch pedal is approx 1” below the original
clutch rod hole. Note: the existing pushrod was not long enough to mount
the heim joint.
An extension was fabricated by taking a 1.5” section 5/8” steel rod,
center drilling and tapping with 5/16-24 threads, and attaching one end to
the pushrod and using a piece of 1” all thread to attach to the heim joint. |
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Slave Throwout Rod: The photo below is the CNC 1312
Adjusting rod, after it has been modified for use on the T-5 clutch arm. The adjusting portion of the adjusting rod
was discarded, as well as the lock nut. The hex shoulder of the rod had to be
ground off flush with the rod.
A 5/8” x 2 ½” bolt was acquired,
and then center drilled & tapped to fit the 3/8-24 threaded adjusting rod. Since the adjusting rod comes treaded only
approx 1”, the last 1½” of the bolt is drilled slightly larger for the rod to
fit in…then start threading. The last
step is to cut bolt head off at the thread root and screw onto the threaded
rod.
The large hex nut becomes the
shoulder which actually engages the clutch throwout
arm. The second hex nut is a
locknut. The threaded portion of the
5/8” bolt fits through the arm and acts as a guide.
Clutch Fluid Reservoir: Photo below shows the location chosen for mounting the
remote fluid reservoir. This spot is
clear of the brake M/C, clear of the throttle linkage, and mounts high on
the firewall. The reservoir was
scavenged from a late 80’s S-10 Blazer.
I’m sure it’s similar to most any late 80s GM truck. A 1/8” NPT to 1/8” inverted flair fitting
was screwed into the CNC M/C, then a 3/16” brake line was formed to
route to the remote reservoir. The
only concern is to make sure the reservoir is the highest point in the
system.
The slave cylinder attach bracket is
the biggest freeform portion of this project.
There are two “ears” on the T-5 which are in the correct position to
hold a horizontal bracket. The holes
are 3/8” in these ears are 7” apart OC. The bracket should be made of ¼” plate and
has to be shaped in such a manner as to clear the surrounding structure. The
Vertical face is welded perpendicularly to the long arm, and provides the
surface to mount the slave cylinder.
These slave mount holes are 2 3/8” apart
OC. Note in the photo below, how the
bracket makes room for the slave cylinder, yet works around the boss
structure of the transmission.
You will need to fit check in order to find where to weld the vertical face to the horizontal, but the upper hole is roughly 5/8” above the centerline of the horizontal plane, and ½” forward of the forward most horizontal attach bolt hole. I know that is confusing, but if you make templates and lay them out, these dimensions should help.
Parts List/Sources/Prices (March05)
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Parts List: |
CNC 711-3/4 Stainless Steel
Master Cylinder
CarShop Inc. |
$61.95 |
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CNC 305-B Push Style Slave
Cylinder |
CarShop Inc. |
$49.95 |
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LONGACRE 2805 Hydraulic Clutch
Line 36” |
CarShop Inc. |
$28.95 |
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CNC 1312 ADJUSTING ROD FOR 305-B |
CarShop Inc. |
$13.95 |
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5/16-24 Ball Joint Rod End |
McMaster |
$5.50||
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Remote Clutch Reservoir |
Salvage Yard |
$10.00 |
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Clutch Arm Return Spring |
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$7.00 |
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¼” x 12 x 12 Plate Steel (Slave Bracket) |
Scrap Iron |
¼” x 4 x 4 Plate Steel (Firewall Plate) |
Scrap Iron |
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Miscellaneous bolts, washers, screws |
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Total: |
$175.00
Hydraulic Clutch Line: The Longacre 36” braided
stainless steel line is more than adequate for running the fluid to the
slave cylinder. I ran it down under
the steering column, tied it to the speedomer
cable, then ran it back along the fuel & brake
lines. From there I made a 180 turn
back along the transmission mount and up to the short hard line shown in
the photo to the right. It is
secured with zip ties in increments and is out of the way of any exhaust
pipes.
Adjustment: After
the system is installed and bled, the 5/8” Hex bolt must be adjusted to the
proper location against the clutch release arm. After experimentation, I ended up with
approx. 3/16” forward “push” on the arm after it’s
initial engagement of the throwout bearing
against the clutch. This put the
full release of the clutch roughly between the lower ¼ and 1/3 of the pedal
stroke. You’ll need to experiment
with this to make it feel right.
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Note: missing from the photo above is the
return spring. I used an emergency
cable return spring and cut it down to the right size. It mounts in the open hole shown in the
top of the bracket pictured above.
The other end mounts to the outer hole on the clutch rod, and pulls
the rod taunt against the pushrod. Bleeding Instructions:
DO NOT PUMP THE
PEDAL |