Clutch arm problem

[WRGREENER]

72/911T: CLUCH ARM IS NOTHING LIKE THE PET PICTURES FOR MY YEAR. I DID FIND A LOOK-A-LIKE IN THE 1977 PET (ATTACHED). THE OLD CABLE HAD NO "CLEVIS" ATTACHMENT, JUST A SMALLER NUT (EXTERIOR ~11MM WRENCH SIZE) AND A LARGER BACKING (EXTERIOR 13MM WRENCH SIZE) NUT.

MY QUESTIONS ARE: IS THERE A SPECIAL "CLEVIS" FOR THIS ARM? OR DOES THE SMALLER NUT "ACT AS" A CLEVIS? OR WAS THE FACT THAT THEY ARE TWO DIFFERENT SIZES AN ARTIFACT? AND WHAT IS THE VERTICAL DROP DOWN PORTION OF SAID ARM WITH THE HOLE (THAT LOOKS LIKE SOMETHING SHOULD GO INTO?

[Flat6pac]

The arm youre looking at is for 75 with the cross over pipe exhaust. The part you require for a 72 is part #5 and cable to match. If you have the 75 piece you require the 75 cable to match. Either are useable as a set for your application.
Bruce

[WRGREENER]

Think i've got it.. 72cable=#5, 75 cable=#6... I am guessing that cable for 6 is longer and routs around the end of the arm and adjusts at that lower "tit" (& not thou the hole at the end of the arm). With that config. Do you use a dust boot?
Wayne

[Flat6pac]

There should be a dust boot for the cable, grease liberally inside the housing of the cable.
The difference of 2, in short time I couldnt find the 3rd
Bruce

[WRGREENER]

The bottom arm is on my 72. The only difference is that mine has a hole dead center of the "v" grove. Said hole lines up with the cable from front of car through trany protrusion (that retains cable). My cable fits perfectly through the hole and alignment is great.

Looks like these two ar about the same length... Should not the lower arm be shorter to allow for alignment (since the cable turns 90 around the end vs the trundle assembly)?

[Flat6pac]

I thought the moment arm was different and needed more leverage but together you and I can see I was wrong.
Bruce

[WRGREENER]

Here is the configuration of my arm. Note the hole (not shown in the photo that bruce generated) that is in my arm. This hole has perfect alignment with cable as it passed through the trany support. Factory provided hole or drilled by others?
Is this typical or a modification by others.

[Flat6pac]

Looks like you bend the cable each time you use the clutch. Your cable is for the correct application but you flexing the cable with each use on the wrong arm.
Bruce

[WRGREENER]

That is exactly what happened. The threaded shaft snapped at the face of the arm thus loosing the back part of the shaft and nuts. The strange part is the original cable has lasted 20 years+ with out snapping. The new one snapped in 80 miles. Think factory cable is worth it??

[john walker's workshop]

somebody drilled that hole.

[WRGREENER]

Ok, the hole is drilled. What is the difference between a hole and a trundle (which has a hole)? If the alignment is good and the adjustment is proper, what is the harm?

[Walt Fricke]

The clutch arm which requires the cable to bend 90 degrees seems like one of those ideas which might have been great for some reason (geometry?), but in practice doesn't work too well.

The simpler arm for earlier cars is, accordingy, hard to come by and more expensive. These undesireable arms are a drug on the used market.

As this discussion shows, just drilling a hole didn't work out well either. Plus it shortened the lever arm some.

Here is a way to use some scraps of square tubing to convert one to the other. There is an extra hole in this piece because I didn't get it quite right to start. I also ground the groove in the arm a little, but could have avoided that if I had drilled the rear hole a smidgen farther out.

Yes, this isn't quite as self-aligning as the V block piece, but pretty darn close.






This worked great and did not put the threaded rod end (or, more importantly, the swedge joint where the cable joins it) into a bending mode.

[WRGREENER]

This worked great and did not put the threaded rod end (or, more importantly, the swedge joint where the cable joins it) into a bending mode.[/QUOTE]

NICE ENGINEERING. I AM NOT SURE I UNDERSTAND THE BENDING THING. IT IS MY UNDERSTANDING THAT GIVEN THE RIGHT LENGTH CABLE...THE THREADED ROD AND ITS SWEDGE JOINT WOULD CLEAR THE "BEND" OR RADIUS TIP AND ONLY THE CABLE WOULD BE DOING THE BENDING OR ARTICULATING?

ALSO, ARE THE LENGTH OF THE TWO ARMS DIFFERENT? e.g. CENTER OF SPIN TO CENTER OF TRUNNION / CENTER OF SPIN TO RADIUS TIP SEEM TO ME THAT THE OVERALL LENGTH OF THE TRUNNION VERSION WOULD LONGER BY 1/2 THE TRUNION AND THE THICKNESS OF THE "C" SHAPED HOLDER.

[Walt Fricke]

The drilled hole in the stock arm version induces unwanted bending. The funky stock piece doesn't bend the swedge, but does bend the cable around a rather sharp radius. Lever arm length close enough to the same for all three stock systems (not counting the harp spring version) as not to matter.