72 clutch rod adjust?

[72SB]

I have about 3" of pedal travel before disengagement which makes the actual point of disengagement/engagement right off the floor. I pulled the inspection cover and clutch appears to have been replaced not many miles ago and disc has a lot of material left so assume I can make adjustment to the threaded rod under truck.

Would I loosen jam not then tighten the nut on rod to reduce pedal travel, or loosen the nut?

[Accelo]

Make the rod longer and then secure it with the jam nut.

[72SB]

yes that was it....does the rod go through the clutch fork in inner or outer hole for 6 cyl?

['68OrangeSunshine]

Originally Posted by 72SB

yes that was it....does the rod go through the clutch fork in inner or outer hole for 6 cyl?

I have an SM465 behind a 292. I have tried both positions. Right now, my Lower Clutch Rod goes thru the inboard hole of the Clutch Fork. The outer hole has my Clutch Return Spring, the other end of the spring goes into a hole in the frame on the drivers side.

[72SB]

???, well I don't have a spring attached to the other hole. Currently the rod is in the outer hole

Will see if there is an illustration showing which goes where for the 250 6 cylinder. With that said, clutch works fine.

I have a return spring on pedal inside cab...assume that is stock

[72SB]

Well after thumbing through the Assembly Manual (WTF they can't include a index) on about the last page there is an illustration showing a return spring for the fork, #4

It appears it attaches to the inner hole (engine side) of clutch fork and other end to a hole in the ball crank plate on frame.

I don't have this spring. Will do a search but I suspect I will need to find a suitable donor spring for something like this.

[67 twins]

Originally Posted by 72SB

Well after thumbing through the Assembly Manual (WTF they can't include a index) on about the last page there is an illustration showing a return spring for the fork, #4

It appears it attaches to the inner hole (engine side) of clutch fork and other end to a hole in the ball crank plate on frame.

I don't have this spring. Will do a search but I suspect I will need to find a suitable donor spring for something like this.

I don't know what you are looking at there but the clutch fork is not on the same side as the starter on a left hand drive pickup truck. What are you working on? And does that illustration apply? I don't think so.

[RichardJ]

I can't read what is at the top of that page, but it appears to be for a Right Hand Drive application.

[72SB]

I have this assembly manual. Yeah the illustration is "confusing" relative to starter outline. These Repop manuals are like this for my 67 Camaro also. Some aftermarket company looks like they Xerox or scanned original but the top and bottom of whatever the original was is only partially there. No Fing index to find anything so its like looking up a phone # for someone in a non-alphabetized phone book. After turning every page...I found the image a few pages from end of manual.

In any event it showed me there was a clutch fork return spring and those are available at LMC, Brothers, etc.

What I am not seeing though is where the front end of the spring would attach, at least on my 72 6 cyl....so I just improvised with a L bracket and a spring I had. For the purposes of a return spring, it works.

At some point PO replaced the clutch so the original spring, assuming it had one, is gone.

[Accelo]

I found this in a forum search.
Full credit goes to Mbeef61
There is a hole in the frame. Attaches to the fork and then to a hole in the frame. This is the only pic I have of one at the moment. 71 4 speed

I added a couple other pictures, seem this is a fairly difficult shot to get clearly.

However, the proof is in the function. Looks like you have a perfectly functional return spring. Kudos to you.
Cheers

[72SB]

I suspect these springs aremostly tossed when clutch or other work is done along its 50+ year life.

Any form of a spring that just holds fork away from TO bearing so it does not constantly press against pressure plate and or rattle while driving.

My truck shifts fine other than when I recently left a cruise and felt I really needed to push clutch all the way to floorboard to disengage. Adjusting the rod about 1/8"-1/4" resolved that.

FWIW this is the one size fits all (# 10), aka cut and bend as needed depending on engine application, that LMC has. It does not appear to be like the pic in post #10 above.

I assume this spring would be stretched forward of clutch fork. I will look again for a hole in frame that given the "correct" spring would attach. But at the end of the day any spring attached somewhere should suffice. Given they are $3 I will add one to the next order I make at one of the parts suppliers.

https://www.lmctruck.com/1967-72-che...tch-components

this appears to be the spring post 10 shows

https://www.classicparts.com/1963-72...20group%20%231

[Steeveedee]

You should have ~.5" of free pedal when the clutch is adjusted properly. The spring should take any pressure off the TO bearing when the clutch pedal is released or premature wear of that bearing may occur.

I have a copy of the FAIM index. I'm hoping the make the next meetup on the 18th in Thousand Oaks. I can bring the file on a thumb drive, or email it to you.

My FAIM also shows LH Drive as the only option. Pretty lame.

[72SB]

Thanks for additional pics Accelo. Based on the added illustration it shows fork rod on inside (closer to engine) hole of fork and spring attaches to outer hole then to hole in frame a good 1' forward. It would appear this spring has long legs and a 1 1/2"-2" coil segment. Not seeing a spring sold that has that shape but again any spring attached somewhere does the same thing.

My rod is outer hole and improvised spring is inner. End of day it does what it needs to. I can see the rod would line up flipping it to other side of Z bar arm to use inner hole but would need to source a spring long enough to hook to frame.

Also see where a NSS would go on interior pedal. I don't have one and don't know if 72's had them. I will look for the pigtail under dash if there is wiring.

Always a path of discovery going over these trucks and finding some WTF moments.

[72SB]

Originally Posted by Steeveedee

You should have ~.5" of free pedal when the clutch is adjusted properly. The spring should take any pressure off the TO bearing when the clutch pedal is released or premature wear of that bearing may occur.

.

Yeah Steve I have more than .5" free play in clutch before clutch starts releasing. More like a few inches. Now with fork spring the fork is not putting pressure on TO bearing but frankly it was not before the spring. There was quite a bit of slop in the rod/fork as you could just move the rod easily by hand. Clutch disengagement/engagement was pretty much off the floor previously, so I did extend the rod adjusting it but only have about 1/4" of adjustment left in the rod now.

Based on looking at clutch, it has been replaced at some point and is relatively clean looking. Disc thickness appears normal.

Given someone has been in there before, IDK but assume the rod length is original. I can see on threads where it was adjusted considerably shorter at some point in its life but I can't image disc has worn to the point it would eat up over a 1" of thread length to adjust where it is now. Maybe because its in outer hole vs inner on fork. It otherwise works fine, shifts smooth.

['68OrangeSunshine]

Originally Posted by 72SB

Well after thumbing through the Assembly Manual (WTF they can't include a index) on about the last page there is an illustration showing a return spring for the fork, #4

It appears it attaches to the inner hole (engine side) of clutch fork and other end to a hole in the ball crank plate on frame.

I don't have this spring. Will do a search but I suspect I will need to find a suitable donor spring for something like this.

Your illustration from the ''Assembly Manual'' shows the clutch linkage set up for an L6 truck destined for Overseas Export with Right Hand Drive. The UK, Australia, New Zealand, South Africa, Japan and some island nations with a former British colonial history might be their destination. Also the USPS sometimes contracted for RHD vehicles, so the postman could reach the mailbox from the relocated drivers seat. Mostly Jeep/Mopar products, these days.

Any generic spring from an assortment found at the autoparts store would work. Offhand, I think a 12'' unstretched spring will work. Some have a premade hook at one end, and a long length at the other, so you can bend in a hook where you need it.

[RichardJ]

You're missing a part that goes on the end of the lower clutch rod.
In the first image it is item #21 and goes on the end of rod #20. It just slips on and is shown in your post #6 above as lubrication point 101.
I saw another thread that shows this item and they threaded the rod to hold it in place, but that is not necessary.
You should get the correct spring and connect it on the frame and not the engine block.

In the drawing, rod #26 is at a strange angle. This drawing may be for a Forward Control Vehicle where the peddle assembly is above and ahead of the bellhousing.

['68OrangeSunshine]

BTW, P/N 21 in RichardJ's diagram is called a ''Pivot Nut'' or ''Nut-Pushrod,'' even though it's not a nut or threaded at all. I had one break apart on me, coming off the freeway on a hot Tucson day. Over-50 year old metal, plus my bad habit of dropping the clutch pedal and jumping on the accellerator in high speed manuevers precipitated the failure...
I had called a tow truck, but in the 2 hours they were expected to get to me, I crawled underneath -- after the headers cooled off -- and extended the lower clutch rod throw by moving the jam-nuts aft a couple inches. Got home OK, and even ran it to work until a fresh pivot nut arrived.

Putting the lower clutch rod and pivot nut in the outer hole does give more leverage.
I also have a '71 GMC Jimmy K/1500 [V8 350/SM465/NP205/12-Bolt Posi, 3.73]. The PO machined threading on the rear tip of the lower clutch rod so after it goes thru the pivot nut and the clutch fork, it's captured by a lock nut. Extreme 4x4 mod, I guess. Never seen another one. But I kept it on.

[72SB]

Originally Posted by RichardJ

You're missing a part that goes on the end of the lower clutch rod.
In the first image it is item #21 and goes on the end of rod #20. It just slips on and is shown in your post #6 above as lubrication point 101.

Appreciate you noting the missing part. That would explain why I was about to the end of rod adjustment and would verify outline on threads where adjusting nut "used" to be

I was able to find it for $9 and also the correct spring shown by Accelo for $7

I also found the fork to bellhousing boot so when the parts get here will be able to rectify this back to as made condition.

Another mop up after someone took stuff apart and did not replace it all. Likely during a previous clutch swap

Found the parts on Four Speed Conversions and Classic Parts.com

[72SB]

Got the clutch fork return spring, pivot nit and dust boot installed. All good now.

['68OrangeSunshine]

Pure Clutch Porn.

[Accelo]

How many posts does it take to fix a conglomeration of parts and return them back to stock and adjust a clutch?

20 posts.

Great job.

BTW it matters little which hole the rod goes into. The women and stop and go traffic will like the outer hole. Adjustments will not be as particular either.

The inner one for the strong foot type.

It doesn't matter which motor you have. If you replace the GM clutch, with a heavy duty pressure plate, you may prefer the outer for from more leverage.

Cheers.

[72SB]

Yeah is good to be able to find these kinds of parts. The place I got the pivot nut from said it was NOS. When I put it on, I found the retaining lock nut only goes on the rod about 1/2", if that, before bottoming out on thread on rod. With this new pivot nut against the ridge of the rod there was quite a bit of slop (read movement fore and aft) to the point the pivot nut cold turn "out" of the recess notch in fork.

If you note in RichardJ pic that pivot nut has a deeper shoulder than the one I got. I added the 1/4" spacer.

Working without a net as the truck did not have these things when I got it and it's been about 50 years since I have had a Z bar mechanical clutch truck or car and not knowing how long, what shape, the return spring is I had to "improvise" but in the end I got there. Fortunately finding these parts made it a simple job. Heck, didn't even need to raise the truck to do the fix.

My clutch now disengages/engages much higher off the floor and certainly has a better feel in terms of pedal resistance vs not having the fork return spring. After driving it I may adjust the rod shorter to bring the engagement/disengagement point lower than it is now. This will take any tension off the fork though from return spring so I may have to use a small L bracket bolted to hole in in frame to allow the forward spring attachment to be about 1/2" further forward thus keeping slight tension on fork. IDK if the return spring is NOS or repop. My guess is NOS but who knows. In any event, just like using the 1/4" spacer for pivot nut....some "adjustment" is sometimes needed to make it work the way one wants. I don't want to cut the spring down any or drill another hole forward in frame so a simple L bracket will suffice.