Heim Joint Clutch Pedal Modification

By Ron Butts

Well I finally got tired of pushing the clutch pedal thru the floorboard to shift, on my 1989 Ford F-350 Crew Cab and got the much discussed modification done. While digging around under the dash I found that the firewall had the TSB90167 done for the structural weakness. The TSB uses the existing firewall area and installs a strengthener plate to the firewall for more support. There are a couple of options to this depending on the extent of damage or weakness to the firewall.

Please note that this modification is purely a working creation and should only be used as an alternative to repairing the clutch pedal assembly when the failure of the nylon bushing has been damaged due to wear and allowed to cause further damage while going un-repaired.

If the clutch pedal bushing has been neglected and not checked or replaced, over time, it will cause damage to the dowel pin on the pedal assembly and to the master cylinder pushrod itself. In my case, it had been neglected by the previous owner to the point that the pushrod had become egg shaped, and the dowel pin had worn one third of the way through. With the assembly being that worn, it was causing great difficulty in shifting from a neutral position to first or reverse. At this point there are few options to repair the assembly to obtain proper clutch activation. One must either replace the tab on the pedal assembly and the master cylinder or use this modification that has been discussed by several members of the Ford 6.9/7.3 IDI forum at www.oilburners.net. The modification took about an hour and a half of my time and was not that difficult to complete if you have the proper tools to do the job.

Preparation

The photo below was at the start of the project. One of the ends had already been cut as I had jumped the gun a bit. You can kind of see the wear without a bushing as the nylon bushing had been completely disintegrated. Note, the pushrod had been rotated 90 degrees to better view the damage and the tab on the clutch pedal had been removed already.

I found it was easier to remove the retainer nut on the tab on the clutch pedal and remove it to grind the weld off the backside. To remove the tab, I found that using a short pry bar on the far side of the clutch pedal assembly was the best place to pry from and allowed the tab to “pop” off. Once the weld was ground off, one swift tap removed the press fit rod end and left a nice 3/8" diameter hole for the bolt. No drilling will be required on this piece.

Note: When removing the tab, make sure of its location in correspondence to the pedal assembly to allow proper pedal travel upon reinstallation. The cuts made on the pushrod are noted below in the photo. I used my Dremel tool with the 24" flexible cable extension, as room was sparse. To cut the eye off the push rod I used one of my old chainsaw sharpening grinder bits and went at it from the inside out where the eye meets up with the shaft.

Once I got it close then I switched to the outside of the eye and got it pretty close when she gave in. Had to wait a few minutes in between because the metal kept getting hot and my 3 yr old had run off with my needle nose vise-grips. About the only thing I had to get in there was that or my hand. This can also be accomplished by using the cutting wheel discs that are also available for the Dremel tool and would be a little easier, but have plenty of cutting discs handy because the push rod is hardened and will take some time to cut thru. I found that it was better to leave as much material as possible on the push rod for the heim joint to have some “meat” to hold onto.

The next step of the process is to prepare the heim joint for installation. With a little help from some friends of mine with a drill press, we drilled the heim joint and tapped it for a ¼”–20 set screw and installed the set screw with a retainer nut onto the joint. After I got things cleaned up the best I could on the push rod, I then took another bit and ground the threads off the inside of the heim joint as things were still a little snug and the joint was threaded but not needed for this application.

The photo below shows the push rod all ground down and cleaned up with the clutch pedal tab reinstalled awaiting assembly.

Installation

The shaft length was just right for the heim joint and no further touching up needed to be done, which gives ample room for travel. Full extension of the clutch pedal will put the end of the heim joint right up to the face of the clutch interlock switch. Once installed, there will be no more slop at the top of the pedal and will provide constant pressure all the way to the pedal stop to properly engage/disengage the clutch. To install, simply slip the heim joint over the end of the clutch cylinder push rod, and tighten the set screw and locking nut. Insert the 1” long bolt through the clutch pedal lever, being sure to use flat washers on both ends. Tighten the nylon lock nut just enough to hold it firmly, yet allow the pieces to rotate against each other. See the photo below.

Below is a finished look at the modification installed and now operational in my truck.

Items needed for this modification are:

1- 3/8" Heim joint made by Aurora Bearing Co. Aurora IL part number CW-6.

1- 3/8"x1 1/2" grade 8 bolt
1- 3/8" nylon stop nut
1- 1/4"x 1/2" set screw
1- 1/4 20 nut
4- 3/8 flat washers

Tools needed:

Drill press

Tap and die for ¼”-20

Dremel tool with cable extension and cutting discs and grinding bit

Socket set

Small pry bar

Needle nose pliers

Punch

Bench grinder

Hammer

Good luck and keep on truckin’, you'll love it!

Ron Butts

Editors note: Ron is an accomplished mechanic of many years, and serves in the United States Naval Reserve working on heavy trucks and equipment and is a respected member of the Brotherhood of Oil Burners.