Clutch linkage
 

This was posted in another thread, https://www.speeddirect.com/index.php/rod-links. Says it needs modification to work on Pontiacs LeMans/ Tempest. What mods are needed ?

On a first guess, I would say that the long rod would need to mimic the shape of the factory rod from the clutch pedal arm to the "Z-Bar" (to get thru the firewall properly and work).
The info does not say what the diameter of the rod is but it looks like it is a larger diameter and a unnecessary size increase.
How it attaches to the Z-Bar is a question. same deal with the Pushrod.

The Pushrod for the bell housing throw out bearing "fork" has a special small diameter pin that fits the lower hole of the Z-Bar and allows adjustment.

The lengths are designed for proper geometry for the Pontiac Clutch linkage.

That would be enough reason for me to not use the parts in the link as they expect you to do the engineering on their basic hardware for a Pontiac fit.

The are coming out and telling you that you have to mod their basic parts. Buyer beware.

Tom V.

Their literature is a little misleading. There is really nothing metal to metal in the factory clutch linkage, except where the lower rod pushes on the clutch fork, and I see no solution for that, even in this kit.

On the factory stuff, the pivot for the clutch pedal and rod to the top of the Z bar as well as the lower part of the Zbar for the short rod should have bushings with the same clevis or clips used on the shift linkage, so it's all bushed and lubricated. Could even take those plastic bushings out and go bronze for more positive clutch action if you wanted.
Even most of the factory Z-bars have a provision for a grease fitting, just remove the little factory red plug that GM put in many of them and screw in your zerk fitting. And if you don't like the Z bar on the ball stud deal, there are Z bars out there on roller bearings if you want to get fancy.

That deal makes about as much sense, (vs the factory linkage as mentioned by Formulajones), as putting a rain coat on an elephant. GM Engineers were not stupid.

Tom V.

They need to make it just like the GM Engineers did, as Tom V. put it, that's the only mod needed.

To say the least. Speed Direct quote-“muscle cars of the 60’s and 70’s. In fact can be a real nightmare" :oogle:

I don't find anything nightmarish about it, on the contrary you need to be able to feel it, like reading braille.

Word up!



Frank

Shiny and Chromed does not make the part function any better vs GM's design.
I will not be crawling under any manual trans 64/72 GTOs to see the chromed
linkage for the clutch hardware. If it makes you happy go for it.

Tom V.

I am sticking with the stock linkage. It works. I had seen the ad before, just wondered what mods were needed.

I can tell you when I put a heavy 3 Finger B&B pressure plate in place of the diaphragm on my 64 Impala 409 I bent rods until we welded extra support on them. Mainly the pedal to Z bar rod.

Yeah if you get into the 3 finger stuff that is super stiff there might be some things that needs to be done to the linkage. For sure the plastic bushings at the pivot points won't last very long.

I swapped a 67 mustang over to a bearing Z-bar several years ago because the owner wanted to try and make the clutch feel smoother. I can't remember if I did anything with the rods or not on that one, but he had a 3 finger style pressure plate in there, it was like driving a dump truck.

The bearing style Zbar didn't do much for it and ended up switching to a diaphragm pressure plate. He was happy after that, lol.

Lot of truth from Skip Fix and Formulajones in last two posts.

I used a different height Clutch Fork Pivot Ball in my Lakewood shield and the pressure was not that bad to activate the clutch. Even my future wife could depress the clutch and drive the car with the Borg and Beck system I had. I spent time dialing that Pivot Ball Height in after I ordered all of the different height Pivot ball studs from Chevrolet.

Tom V.

I cut off the pin on the left stud and made the lower section of the stud the same as the other 3 studs.
There are 4 different height studs even though #1 and #2 are close to the same height.

I've never seen bushings in the Z bar or pedal where the rods mount, it is straight metal on metal.

People have modified them to use a shifter bushing, but you have to grind off the flange, or you won't get the pin in it. I've seen some drill the holes on the Z bar out and slip a piece of brass tubing over the rod end, but finding one that fits is an issue, not to mention they will wear out faster too.

If you've ever looked at a worn rod end where it goes into the Z bar (or pedal), you will know exactly why the Speed Direct setup was made.

Only mod I can think of is yes, there is no bend, but it can be straight, and just open the hole in the firewall a little at the bottom. The seal/boot will still fit.

Call them, there's a note on the part that says to call for more info.


.

Exactly. No factory bushings

I’ve made my own rods with heim joints similar to the one above for my 66 GTO. Pretty simple to make, and yes, a straight rod works just fine. Not sure why the factory rod was shaped the way it was.

This is the setup I made recently for my 64 Lemans.

I salvaged my 65 GTO's original Z bar by drilling it for the normal Hurst size shifter bushings or some insert washers don't remember which I found to fit better. Holes were getting egg shaped. Steel seemed a little harder to drill than I thought it would be.

Singleton what clutch fork is that?

https://www.speedwaymotors.com/Speed...ork,37080.html

Just for laughs...Here is the z-bar that came with my '64 GTO - talk about engineering vs. hack-job. :eek:

http://forums.maxperformanceinc.com/...1&d=1603138776

I have one like it and it is for a Chevrolet application Corvette I believe.
I installed it because the factory rod nose sometimes comes out of the throw out bearing fork locating depression on a quick clutch release.

Tom V.

The factory clutch forks (not the pin style) are supposed to have a spring on them that runs from the fork to the Zbar so it holds that rod from falling out of the fork on the more common style. My Z is that way.

You are right Tom, the style that has the pin holding the rod is Corvette. I have that style in the Nomad and it's all OEM 66 Corvette drivetrain.

I must have had a relaxed spring on the stock pieces as the connecting rod that goes into that fork was not in the depression on the fork and was jammed in the spring twice.
At that point I went to the corvette parts.

As you know from your experiences with the Nomad, those are some good parts to use if you had the issues I had.

Tom V.

On my lemans sprint, the connections were all metal to metal. After two linkage failures I added Heim joints at all wear points. Going to do the same to my current GTO.

George

I used some fairly hefty clutches and plates in my 68 Bird but nothing that required any fabricating or strengthening of the linkage.

I did however have to replace the bushings in the bellcrank on occasion, but always took that as a necessity from normal wear and expected.

Also I would attribute the bends or offsets in the rods on any particular application to be for clearance or something applicable.


Frank .

If the clutch rod pins are that worn out, then it is most likely that the hole on the clutch pedal that it goes into is also worn/elongated. I welded mine up and redrilled it.

On my '68 I used the factory push rod, but cut off the worn ends, threaded the rod's ends, and added heim joints.

I also added Shell Needle Roller Bearing to my clutch pedals to replace the factory steel spacer sleeves.

Some really nice fabrication work there, PontiacJim1959

Tom V.

Tell me more about this shell bearing modification. Have a part # for them?

I agree.

In addition if the bushings on the peddle shaft are maintained along with the bellcrank bushings there is much less wear in the pin hole areas due to absorption.

Holes get elongated and pins get worn because bushings aren't serviced either due to neglect or the fact they are overlooked, maybe even not known to a previous owner to exist.

With those bushings worn out, possibly even gone, it puts allot of extra pressure on the entire clutch linkage and can take significantly more pressure to activate the clutch.


Frank.

I have flanged bushings to fix the egg holes / bronze 5/16 i.d. ,if in need.

Ditto, but thinking one could use roller pilot bearings maybe?

.

They've had them for mustangs for years. Not overly expensive either

https://www.summitracing.com/parts/sdk-c5zz2478rbmk

I've installed these on a Mustang, but these same kits I'm told are also used on GM as well with a little ingenuity.

BTW, for anyone wanting to make their own clutch rods, or manual trans shifter rods etc. Easiest way is .500” mild steel tubing, .095 wall, which has a .310 ID. This ID is the right size for a 3/8 24 tap, so no drilling required.
Just need a R/H and L/H 3/8-24 tap and the appropriate left and right rod ends, (which are pretty cheap at $5 ea). The clutch fork from Speedway is $39.95.
https://www.speedwaymotors.com/Speed...ork,37080.html

My factory GM set up is good to go in the GTO.

Tanx for posting though as others may be in need.


Frank

My 70 Bird bell crank was tougher than the linkage pins it didn't elongate I just got 2 new stock linkages the hole in the pedal arm was elongated I welded it shut and re'drilled not at all to difficult and it was like day one again

But being a retired aircraft technician I might go spherical rod ends someday for the halibut but it's not to urgent

.

Same deal with my original Z-Bar. The Z-Bar was fine, the Threaded rod end (square) that threads on the clutch rod was worn badly where the hair pinned pivot went thru the Z-Bar.

I did change that to the heim joints that attached there and at the corvette fork.
I left the stock stuff inside the car that attached to the other end of the Z-bar as it was fine.
I did all of these mods over 35 years ago.

Tom V.

Here you go, this is my complete write-up on the upgrades which includes my parts list and photos. Have yet to install or see if this is going to work in actual use, but it seemed like an upgrade to me that will hopefully work in practice.

https://www.gtoforum.com/threads/clu...0/#post-893341