ZF 5 Speed Heim Joint Mod

Master Cylinder Pushrod Modification for 1987 - 1997 Ford F-Series

The "heim joint mod" for 1987 to 1997 Ford pickups equipped with the ZF 5 speed manual transmission eliminates problems associated with the infamous plastic "Mickey Mouse" bushing located in the eye of the clutch master cylinder pushrod. The plastic bushing is notorious for wearing down and/or cracking, allowing for excessive play between the pushrod and clutch pedal swing arm. In extreme cases where the problem is not addressed promptly, the eye of the pushrod can actually begin to eat away the pin on the end of the swing arm. Ultimately, this connection is the source of poor shift quality, grinding gears, and the seemingly endless need for more clutch throw.

The heim joint mod for Power Stroke and IDI diesels replaces the factory pushrod eye and swing arm pin with a rod end joint and high strength cap screw, creating a tight connection that will never wear out. You'll be amazed at how such a simple modification can greatly improve clutch feel.

Click any thumbnail image to view fullsize - fullsize images contain important details/model year distinctions when applicable.

Worn clutch swing arm pin and pushrod bushing

The image at left is a prime example of the common problem with the clutch linkage system on the 1987 to 1997 model year Ford diesels equipped with the ZF 5 speed manual transmission.

The "Mickey Mouse" bushing in the clutch pushrod eye wears rapidly until metal-to-metal contact occurs between the rod eye and swing arm pin. The result is a worn pin, which reduces clutch throw and causes a variety of driveability issues including rough, difficult gear engagement and gear grinding. Replacing a worn bushing is only a temporary fix.

Master cylinder pushrod removal

• The clutch master cylinder pushrod is located underneath the dash between the accelerator and brake pedals.

• If applicable, disconnect the connector from the clutch engagement switch and position it out of the way (you may not have a switch).

• Disconnect the clutch master cylinder pushrod from the clutch pedal swing arm using a large screwdriver to pry it off of the swing arm pin. Don't worry about damaging it as it is being permanently replaced.

 

Clutch master cylinder removal

• Remove the two nuts securing the clutch master cylinder to the firewall. For 1987 to 1991 models, the nuts are located on the interior side of the firewall. For 1992 to 1997 models, the nuts are accessible from the engine side of the firewall. All model years require a 13mm socket. Penetrating fluid is recommended if the bolts appear rusty.

DO NOT DISCONNECT THE HYDRAULIC LINE FROM THE CLUTCH MASTER CYLINDER

Clutch master cylinder

• Trace the clutch hydraulic line and remove any retaining clips so that it can be pulled through the firewall. For the time being, let it hang under the hood. Again, do not remove the hydraulic line from the clutch master or slave cylinder.

Clutch pedal swing arm removal

• From under the dash, remove the nut holding the clutch pedal swing arm in place (18mm socket).

Prying on the clutch swing arm

• Remove the clutch pedal swing arm. It will be extremely tight; vice grips and a small pry bar/large screwdriver should be used to simultaneously pry and rock the swing arm. Patience is your friend, you will need to work at it.

 

Pressing out pin on the clutch pedal swing arm

If the pin on the clutch swing arm is welded on the backside:

• If the pin on the clutch swing arm is welded on one side, grind the weld off and then press out the pin in the direction indicated in the fullsize image (click thumbnail at left).

• If the pin is not welded in place, follow instructions in next step.

 

Clutch pedal swing arm

If the pin on the clutch swing arm is pressed in but not welded:

• If the pin on the clutch swing arm is not welded on one side, press out the pin in the direction indicated in the fullsize image (click thumbnail at left).

• If the pin is welded in place, follow instructions in step above.

• You may also choose to purchase a new swing arm entirely. The swing arm comes from the factory without splines. Splines are cut into the swing arm where it attaches the clutch pedal shaft upon initial assembly. Splines can be re-cut into the used swing arm, but the joint is weakened with every new set of splines cut over the original.

• The swing arm is Ford part # E7TZ-7A554-A (1987 - 1997 model years) and the pin will need to driven out as outlined above.

Cutting off the pushrod eye

• From under the hood, cut the eye off of the clutch master cylinder pushrod using a hacksaw. Support the rod with one hand while cutting with the other as to achieve a flush, clean cut - see cut details in fullsize image.

• If the eye is not cut per these instructions, the clutch switch will not fit once the rod end is installed and it will have to be discarded/disabled. A straight, flush cut is desirable.

Installing spherical rod end

• Use a file to deburr the cut zone and dress the edge of the cut until the supplied rod end will slide over the pushrod.

Reinstallation of the clutch master cylinder

• Insert the pushrod into the rod end and tighten down the set screw. The pushrod must be installed completely into the rod end such that it contacts the bottom of the rod end bore before tightening the set screw.

Note - the set screw secures the joint but does not carry any load when the clutch is being used.

• Reinstall the clutch master cylinder, positioning the set screw towards the passenger side of the truck so that it remains accessible in the future.

Installing the clutch pedal swing arm and master cylinder pushrod

• Position the clutch swing arm onto the clutch pedal pivot rod. Do NOT tighten down the clutch swing arm at this point, simply install the 18mm nut loosely so that the swing arm is free to spin.

• Install the 3/8" cap screw through the clutch swing arm and eye of the heim joint snuggly, but do not overtighten. If the bolt does not slide into the swing arm freely, use a wrench to drive it (the fitment is often tight). The allen head of the bolt should be facing the passenger side so that it is accessible.

With the clutch pedal in the up position (pedal NOT depressed) push the clutch swing arm towards the firewall (counterclockwise looking from the passenger side) until all the slop is taken out of the clutch master cylinder throw, then tighten the 18mm swing arm nut securely. This bolt MUST be tight before attempting to use the clutch pedal or the splines will strip.

• Test the actuation of the clutch pedal, then once again tighten the 3/8" cap screw, allen head set screw, and 18mm swing arm nut. After several days of normal driving, it is advised that you check the tightness one last time.