One extremely popular “junkyard” upgrade for classic cars is to install a 5-speed from a 1985-1993 Mustang. Regardless of the year or model of car that the T5 is going in, one major hurdle is to figure out how to actuate the clutch. There are several options, due to the fact that the T5s installed by Ford as OEM equipment used a T5 specific bellhousing, and the clutch fork on that bellhousing is actuated by moving it toward the front of the car where a toploader or T10 bellhousing that might have been OEM on a classic is actuated by moving the clutch fork towards the rear of the car.
These options include using the stock clutch z-bar/linkage with stock bell housing and T5 specific adaptor plate between the transmission and bellhousing, a T5 bellhousing that has been modified to except a traditional type clutch fork so that it will work with stock clutch z-bar/linkage, a T5 bellhousing with the clutch fork actuated by a cable as ford originally did it on the 1985-1993 Mustang, or the T5 bellhousing with the clutch fork actuated by hydraulics.
I have installed a T5 in both my 1964.5 Mustang and my 1962 Galaxie, and in both cases I chose to use hydraulics. For me, part of the advantage of going with a T5 was to eliminate the original z-bar/linkage. That only left me the options of a cable or hydraulics. Cables can work well, but they can also stretch and/or break requiring adjustments or replacements.
Hydraulics on the other hand have proven them selves exceptionally reliable and nearly maintenance free once correctly set up. Lets face it every car on the road, new or old uses hydraulics to actuate the brakes, which means the method, is sound.
Master cylinder
Just like the brakes, you need to have a master cylinder to push the fluid. In the case of a hydraulic clutch room is often a premium due to location of the brake master cylinder and other things attached to the firewall so it is recommended that you get a master cylinder that has a remote reservoir that way you can mount the master cylinder in the proper location on the firewall to easily connect it to the clutch pedal but locate the fluid reservoir where you have room for it. I like the Wilwood universal master cylinder available at many part suppliers and speed shops including speedway motors. It not only has the remote fluid reservoir but also comes in a verity of bore sizes so that it can be correctly sized to the slave cylinder.
Slave cylinder
The slave cylinder is a key components as it is what converts the hydraulic pressure back in to mechanical motion to actuate the clutch. There are many donor cars out that that use a slave cylinder so junk yard parts are available, but I prefer new parts. To the best of my knowledge there is only one aftermarket push type Slave cylinder available even though it is sold under several manufacturing names, and like the Master cylinder can be purchased at many places including speedway motors.
Master cylinder to slave cylinder ratio
When purchasing your master cylinder and slave cylinder you must look at bore size and piston travel. For best results you want the master cylinder to have at least 1.25” of piston travel and a bore size that is either equal or slightly smaller than the bore of the slave cylinder, keeping in mind that most slave cylinder bores are .75” or .825”.
The way hydraulics work, if you use a master cylinder and slave cylinder with equal bores than the pressure required to actuate the master cylinder will be approximately the same pressure applied by the slave cylinder, in other words the pressure required to actuate the clutch by the slave cylinder will be almost equal to the pressure needed to actuate the master cylinder at the pedal (I say “approximately” and “almost” because resistance is created by hydraulic lines which results a slight difference in pressures between the master cylinder and slave cylinder, but this difference is really not to be worried about for the sake of this installation).
In contrast if the master cylinder has a smaller bore than that of the slave cylinder, less pressure is required to actuate the master cylinder than the pressure created at the slave cylinder to actuate the clutch. The reduction in pedal effort comes at a cost of reduced slave cylinder travel. Example if the slave cylinder and the master cylinder have the same bore, 1.25” of piston travel at the master cylinder will result in 1.25” of travel of the piston in the slave cylinder, but with a .75” master cylinder and .825” slave cylinder the difference in bore size will result in about a 17% reduction in pedal effort and the 1.25” of master cylinder travel becomes 1.04” of slave cylinder travel.
Hydraulic lines
Some sort of line needs to be used to connect the master cylinder to the slave cylinder. As with the breaking system there are three man options: rubber hydraulic hose, braded steel line, and hard steel line. No mater which option you choose to go with make sure there is flex in the line at some point other wise the vibrations from the transmission could cause solid lines to fail.
Slave cylinder pushrod
Some sort of rod needs to be used to connect the slave cylinder to the clutch fork. There are rods commercially available that firmly attach directly to the clutch fork, however I do not like these, as they do not allow the joint between the pushrod and clutch fork to pivot as the clutch is actuated. For me a better option is a piece of
threaded rod and a spherical piece of steel.
Mounting bracket
The makers of the T5 were kind enough to supply tabs for mounting a slave cylinder, however the tabs will not bolt directly to the slave cylinder. This means a bracket needs to be fabricated or
purchased pre-made to properly position the slave cylinder and connect it to the transmission.
Firewall support
It is important to realize that for most applications the area of the firewall where the clutch linkage originally passed through is not strong enough to deal with the pressure of actuating the master cylinder and bolting the master cylinder directly to the firewall with out any kind of reinforcing plate would at the least flex and deform the fire wall but more likely could cause the master cylinder to brake loose from the firewall during use. An easy fix for this is a thick steel plate on the inside of the firewall to more effectively distribute the pressure of the master cylinder against the firewall.
Bolting on the slave cylinder and master cylinder
Attaching the slave cylinder and master cylinder to the car in their respective locations is simple. Bolt the slave cylinder bracket to the transmission mounting tabs then bolt the slave cylinder to the bracket.
From there you can install the push rod between the slave cylinder and clutch fork.
Once the rod is installed you need to make adjustments so that there is a little bit of preload on the throwout bearing. Also further adjustments may need to be made depending on where in clutch pedal travel you like the clutch to release. I personally prefer it to release closer to the floor rather than near the top of pedal travel. Finally the hydraulic lines need to be attached to the slave cylinder.
The master cylinder bolts in, in the same fashion, with the exception of needing to drill mounting holes in the firewall and possible needing to enlarge the original clutch linkage hole. As with the slave cylinder the hydraulic lines need to be attached to the master cylinder. Also if using a master cylinder with remote reservoir, the reservoir will need to be mounted and connected to the master cylinder.
Bleeding the system
Once everything is bolted up and the lines have been run the system like brakes needs to have all air removed. This is a two-man job and is critical. Most of the time when people are having problems setting up their hydraulic clutch it is because they have not gotten all the air out. Sense air, unlike hydraulic fluid, compresses, air in the system will reduce slave cylinder travel and causes the clutch fork to not fully actuate. Also as the system the bled you need to examine all connections between the master cylinder and slave cylinder to insure there are no leaks. Bing a pressurized system leaks should be obvious as the air is removed.
Connecting the master cylinder to the pedal
One thing that is critical when doing a hydraulic clutch install is to make sure the master cylinder push rod mounts to the pedal in a place that keeps said pushrod mostly parallel with the master cylinder through a full range of motion. I say mostly parallel due to the fact that as the arc of the pedal changes, rod angle also changes and I have found for best results the rod needs to be angled slightly up from parallel with the pedal in the fully up position, so that it can drop as the pedal is pressed. On my mustang the original clutch hole is only about 1” lower than the mounting hole that I drilled in to the clutch pedal to keep things parallel, but on my 62 Galaxie the hole for the clutch linkage is about 2.5" lower than the pedal-mounting hole. The location of the firewall holes and the need to have the pushrod near parallel to the Master cylinder gave me quite a problem to solve especially on the Galaxie. I couldn't easily relocate the clutch linkage hole and tilting the Master Cylinder down to match the original linkage angle would have required the fabrication of a special bracket. The first option to make it work was to drill a new hole in the clutch pedal and move the pushrod mounting point in-line with the master cylinder. This worked on the Mustang sense the relocation was only about 1” and resulted in only slightly increased pedal effort and decreased pedal travel. Many who have installed a hydraulic set up on a classic mustang have used this technique.
However the 2.5” drop on the Galaxie did not make this an option, and I learned that the hard way. When I drilled the new hole I new that the 2.5" drop from the factory location would increase pedal effort and shorten pedal travel but I figured sense most say their hydraulic clutch requires less pedal effort than stock I would be fine. WRONG!!!! took a lot of pedal effort and the master cyl bottomed out 2" before the pedal reached the floor. I thought OK I will use the higher mount as a pivot and run a 5/8" block perpendicular to the push rod from the pedal to said pushrod to connect it to the original clutch linkage hole. This allowed me to maintain the correct pedal geometry and master cylinder location.
This set up immediately bent the 5/16" pushrod that came with the MC so I machined one out of a 3/8" grade 8 bolt (Man I love have a metal lathe!!!!!!!!!). Bent that one too but not as bad, and I was able to at least actuate the clutch and make sure it worked and that pedal effort was reasonable. The final solution was to triangulate the push rod by threading most of the push rods length and making an adjustable connection to stabilize the rod.
This solution could also be used on the Mustang to reduce pedal effort and maintain the original pedal geometry, not to mention avoid drilling a second hole in the pedal and would probably not require the extra triangulated support.
Over all I am very pleased with the result, the clutch is easy to actuate and very smooth. Also the hydraulics provide an improved direct feel over what I got with the original linkage. In other words I can feel the change in pedal effort just as the clutch releases or grabs, but the feel is crisper than before as there is no longer the flex I was getting from the z-bar and other clutch linkage.
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