plaidside

I just helped a friend who has a 65 small block, install his new clutch kit, LUK, new flywheel and a new repro clutch fork.
Now there is too much free play, so I went to adjust the clutch linkage and there is only about 1/2" left to lengthen the rod.
Another friend of mine, who also has a 65 small block, has the same issue after installing a new clutch are repro fork.
Anyone experience this?
I am thinking of removing the Z bar and re-positioning one of the arms.
Joe

wmf62

there are 2 similar looking forks; do you have the right one?

otherwise, i'd just lengthen the rod, not modify the z-bar.

Bill

plaidside

Thanks for the pictures, I will have to see which one he received from the vendor.
Joe

plaidside

He purchased the correct fork according to your pictures.
As you can see from the photos I ran out of adjustment.
Has this happened to anyone else?
Joe

66jack

Did you replace the lower rod also? Those come in different lengths based on year and application.....BB vs SB...


From JohnZ...


Post #4

https://www.corvetteforum.com/forums...-65-z-bar.html

CORVETTE CLUTCH LINKAGE USAGE



1963-E1966 SMALL-BLOCK:

3832857 Cross-shaft - 135 arm separation, 4.65” and 4.0” hole centers

3819154 Pedal Pushrod – 18” long

3844209 Fork Pushrod – 10-9/16” long (’64-E66)

3819165 Fork Pushrod – ’63-only (integral pin at fork end)

3819152 Pedal Bracket


1965-1966E BIG-BLOCK:

3872962 Cross-shaft - 155 arm separation, 4.65” and 4.0” hole centers

3872961 Pedal Pushrod – 19-1/4” long

3872960 Fork Pushrod – 8-9/16” long

3872963 Pedal Bracket


L1966-1967 ALL:

3888279 Cross-Shaft - 155 Arm Separation, 4-3/4” and 4-1/4” centers

3888213 Pedal Pushrod – 19-1/4” long

3872960 Fork Pushrod – 8-9/16” long

3872963 Pedal Bracket (1966 only)





JPH
12/9/09

wmf62

according to the picture from CC, there is only one upper rod but several choices of lower rods.

I suggest calling and asking about the length of the various lower rods.

Bill

66jack

Check out my above link plus these in the link below

#8 and #13 in this link...




https://www.corvetteforum.com/forums...questions.html

wmf62

interesting, none of those #s match the numbers on the CC diagram, but pedal and fork pushrod lengths vary.....

looking at post #8 of the link above gives an indication of why the rods may be of different lengths due to the arm angles of the z-bar.

BUT, a longer upper or lower push rod, no matter the original application, may solve your problem.

Bill

tbarb

IMO, the best way to troubleshoot issues like this is to start at the clutch pedal and verify the correctness of the clutch linkage parts for your year car.

Start at the bracket that bolts to the pedal and work forward.

DansYellow66

[QUOTE=plaidside;1593170499]He purchased the correct fork according to your pictures.
As you can see from the photos I ran out of adjustment.
Has this happened to anyone else?
Joe

Your an old hand on this forum so I'm assuming it's been verified he has the correct throw out bearing and fork pivot and the fork is engaged in the proper manner to the TO bearing?

The fork does look pretty far forward. Maybe someone changed out the lower pushrod on a prior clutch change to a shorter one to correct some other funky clutch issue.

plaidside

[QUOTE=66jack;1593170658]Check out my above link plus these in the link below #8 and #13 in this link...



Thanks, but I already have that information.

The rod lower is 10 1/2" long and the Z bar and upper rod was not touched.
We used a LUK clutch kit, with the correct bearing, and a new LUK flywheel He also purchased the correct fork.
The odd thing is my other friend has a 65 and he replaced his clutch and fork and he is also at the end of the adjustment.
Joe

plaidside

Thanks but he had the car for over four years with no clutch issues.
I rebuilt the trans for him and the clutch was worn so we replaced it.
Joe

wmf62

we may be getting into Bubba territory here, but i'd do whatever it takes to make it work.

how long is the pedal pushrod?

Bill

cardo0

I had the pin that is only spot welded onto the clutch pedal break its weld - luckily at the end of my driveway. When i looked at the pin it had a large gouge worn into it. So after making a new pin and attaching it will a full circumference weld i still had a difficult time adjusting the clutch.
Inspecting the Z-bar and all the clutch operating rods i found plenty of elongated holes and worn pins. Had to replace all of it for the clutch. I put the mileage of my '74 at either 135k mi or maybe even 235k mi. Something unexpected as a normal wear part but that needs inspecting.

Good luck and hope this helps.

tbarb

I would look at the bracket that holds the pin on the clutch pedal first, the correct location along with the 18" pedal push rod should work. The bracket's pin location changed for 66-67 cars and big blocks and the pedal push rod changed in length from 18" to 19 1/4" long.

MikeM

FWIW. I bought my '65 in '72. It had the original clutch in it. The adjustment nut on the forward end of the upper rod was run all the way to the end of the threads. I assumed that was the factory adjustment.

The car now has about 50K miles on it. I adjusted free play about 15 years ago and the adjustment nuts on the upper rod look the same as in your picture. About two threads back from the end of the rod.

My car is not the only original one I have seen like this. You have to wonder why the design called for a half width adjustment nut of the front of the rod and full width nut on the backside. You also have to wonder why GM redesigned the SB clutch linkage geolmetry in '66(?)
I have even seen some that had NO nut on the front side of the rod and the swivel was pushed all the way to the end of the threads. Don't know if the cars left the factory like this or not. Just an observation.

As long as your pedal stop was intact under the dash, I don't believe it would hurt a thing to remove the front nut to get more adjustment.

Maybe the body is slid back to the limit on the body mounts? Maybe the bellcrank bracket on the frame is welded slightly off location. Maybe the clutch pedal is giving way under the dash?

Lot's of possibilities

DansYellow66

[QUOTE=MikeM;1593176993]

As long as your pedal stop was intact under the dash, I don't believe it would hurt a thing to remove the front nut to get more adjustment.

/QUOTE]

I hadn't really considered this before but that pedal stop bracket is just a small piece of angle iron and easily bent (mine needed to be straightened when I bought it). Also a missing or rotted/broken bumper could allow the top rod to move to the rear.

Good checks to make.

SW Vette

I have the same problem. Turns out the PO put in a "circle track" heavy duty clutch from Summit and an adjustable pivot ball. The rest of the linkage is stock but somehow the clutch rod adjustment nut is all the way at the end and the clutch still engages just above the floor. When its hot I can tell its not even fully disengaging.

To access the adjustable pivot ball I need to pull the entire bellhousing and clutch assembly, is that right? Thinking I may as well replace the clutch, TB, and pivot ball with OEM at that point rather than jerk around with a funky adjustable pivot ball setup.

MikeM

[QUOTE=DansYellow66;1593177085]Based on what I've seen on original '65's, it wouldn't take much to throw off the clutch adjustment to the extreme end of the upper rod. As long as you can adjust free play, not a big deal as the clutch wears, you'll be winding that top nut back toward the firewall, not off the end of the rod.

wmf62

[QUOTE=MikeM;1593179997]Mike
welcome back....

Bill