Erratic Clutch pedal

[Daves69]

.........is in place between clutch rod and z-bar............

Any behind the pedal rod?

 

[oldmanmopar]

It doesn't matter how many insulators you have in. If the fork spring is not strong enough to pull the play out of the linkage it will rattle.

 

[Daves69]

If the fork spring is not strong enough to pull the play out of the linkage it will rattle.

Seems to me the "free play" in the issue is between the bell crank and the pedal "up" travel since the over center spring is out, no?

 

[moparedtn]

Use a good spring on the fork to the bell. It holds all tight. Pulling up on the pedal with a spring just leaves all that play in the slotted holes in the linkage. I just went round and round with the car here. The modifications to the Z bar for the TTI race Headers this guy bought and the diaphram clutch had me pulling my hair out. All is well now and the customer is happy.

This was on a car that came in for a wiped cam. One thing led to another and the whole motor got rebuild. The car was a Rust bucket. I install all motors from the bottom . When going to put the K member back up we saw the frames were rotted. So it took a whole front clip and floors. Then he wanted the engine compartment painted the original color the car came.

It just came back for the clutch and 355 gears. Now he wants rear quarters and trunk floor. Money is no object to him it was His car from the 70's and he just bought it back.

View attachment 601796 View attachment 601797 View attachment 601798 View attachment 601800 View attachment 601801 View attachment 601802

Looks like a sweetheart of a car!
The fork spring on mine is one I fetched from Brewer's and it's stiff. Pain in the *** to get on, in fact.
Yeah, the rattling in my clutch pedal is all linear I think, with the clutch rod bouncing from end to end on its' slotted hole.
Usually not noticeable if one has a spring on the pedal, which of course I disconnected.

 

[moparedtn]

It doesn't matter how many insulators you have in. If the fork spring is not strong enough to pull the play out of the linkage it will rattle.

The fork spring does nothing for the slop upstream of it, including z-bar and clutch rod/pedal. I think that's what I'm experiencing.

 

[moparedtn]

Seems to me the "free play" in the issue is between the bell crank and the pedal "up" travel since the over center spring is out, no?

You are correct, sir - I think. Pedal seems to be bouncing linearly as the clutch rod moves to and fro on its' slot.

Wait, did I just use the phrase "to and fro"? Holy crap, I'm old...

 

[dadsbee]

Why I hook the clutch rod spring to my bellhousing and not the Z bar. Then it takes care of all slop. (yes I know the clips not in final position)

 

[5.7 hemi]

If a hydraulic throw out bearing was used, this wouldn’t be a problem. But I do understand that some do not want to use it.

 

[Daves69]

Out of the box............
Maybe make up 2 nylon insulators to fill in the pedal rod hole excesses? I don't know if the stock retainer clips would hold them in.

 

[moparedtn]

Why I hook the clutch rod spring to my bellhousing and not the Z bar. Then it takes care of all slop. (yes I know the clips not in final position)
View attachment 601837

Re: clutch fork spring...
There actually is a small hole on the bellhousing for the spring to mount to. Other end goes on the designated spot on the fork.
Confirmed that with Dan Brewer on the phone today and it is shown that way in the FSM. I didn't even know some folks hooked them to the z-bar?

 

[dadsbee]

'69 Dodge Coronet / Charger / Dart FSM shows spring from fork notch to a hole just above the pivot in Z bar arm. I was surprised as hell when I read that last year, as I've had it where I show it in the picture for 39 years!

 

[moparedtn]

Out of the box............
Maybe make up 2 nylon insulators to fill in the pedal rod hole excesses? I don't know if the stock retainer clips would hold them in.

View attachment 601843

Similar thoughts have danced through my head as well.
I spoke with Dan Brewer today on this whole mess and picked his brain some:
1. He asked if the fork spring down below had been tough to get on. Yep, it's a pain. He said that was fine then, spring doesn't need replaced,
that it doesn't take a lot of spring tension to keep the throwout bearing off the diaphragm and that was plenty.
2. I described the annoying pedal rattle/bouncing and he asked if I had fashioned a light return spring under the dash on the pedal itself.
He advised to do so, pronto. Asked if my rubber bumper was present. "No sir, that's part of why I'm placing an order with you today."
(I always try to buy stuff from folks who help me like that - I know I'm taking them away from their work)
Bought more clips, another insulator washer, the bumper, etc. today.
3. Asked him about the alarming condition of the flywheel when we took it out for the transmission work (wound up at the machine shop
with it!). With less than 500 miles on it, the condition was unlike anything I'd ever seen. He assured me that the friction material in the
Dual Friction setup does that to flywheels, let's just make sure the throwout bearing isn't riding on the diaphragm, in effect making the
clutch slip imperceptibly just a little bit.
He also affirmed where I have the clutch currently adjusted (just shy of halfway up off the floor) and said that adjusting that only affects
the pedal height, nothing else.

I've said it before and I'll say it again:
Brewer's is a credit to the hobby. I strayed to his competitor once. Won't happen again.

 

[oldmanmopar]

The fork spring pulls the fork which pushes on the adjustment rod which pushes on the Z bar. This all keeps pressure back against the peddle which prevents the system from hanging loose and rattling. Using a lite spring on the peddle only pulls the peddle up for free play.

This can be done with a stiff fork spring which keeps all the linkage pulled back not only the peddle. The fork spring goes from the slot in the fork to the hole in the bell housing. The factory over center spring on the pedal is only to assist the depression of the peddle with a Borg&Beck style pressure plate. The fork spring is to eliminate assembly play and keep the bearing off the fingers.

You have to think with your dip stick sometimes. Been doing this for many many years.

 

[Daves69]

...........The factory over center spring on the pedal is only to assist the depression of the peddle with a Borg&Beck style pressure plate...........

Works in two directions. The over center spring not only assists in the depression of the peddle for a B&B plate spring load, but also pulls the peddle up to the stop to eliminate any flopping around.

One other item you may want to check is pedal bushing wear.

 

[moparedtn]

The fork spring pulls the fork which pushes on the adjustment rod which pushes on the Z bar. This all keeps pressure back against the peddle which prevents the system from hanging loose and rattling. Using a lite spring on the peddle only pulls the peddle up for free play.

This can be done with a stiff fork spring which keeps all the linkage pulled back not only the peddle. The fork spring goes from the slot in the fork to the hole in the bell housing. The factory over center spring on the pedal is only to assist the depression of the peddle with a Borg&Beck style pressure plate. The fork spring is to eliminate assembly play and keep the bearing off the fingers.

You have to think with your dip stick sometimes. Been doing this for many many years.

You're right as far as you go - but it's quite impossible for the fork spring to do anything about tightening up the slotted clutch pedal rod to z-bar joint.
Since the pedal is on the driver end of that, it's free to rattle back and forth - which mine is doing.
As stated previously, my fork spring is new, it's stiff as hell and hard to install. Done deal.

BTW, the over-center spring not only assists with depressing the clutch pedal/operating the clutch, but also serves as the clutch pedal return spring.

 

[moparedtn]

QUOTE="Daves69, post: 910952007, member: 15477"]Works in two directions. The over center spring not only assists in the depression of the peddle for a B&B plate spring load, but also pulls the peddle up to the stop to eliminate any flopping around.
One other item you may want to check is pedal bushing wear.[/QUOTE]
Yes sir, all correct.
I've got a little side to side wear on the pedal pivot, but nothing worth disassembly.

'69 Dodge Coronet / Charger / Dart FSM shows spring from fork notch to a hole just above the pivot in Z bar arm. I was surprised as hell when I read that last year, as I've had it where I show it in the picture for 39 years!

That's actually where it goes on a 6 cylinder.
This is from the FSM (1968 version, but same thing); in this pic, notice where it says to put the fork spring on 440/hemi engines.
That is the exact hole I have mine in:

 

[dadsbee]

Then as oldmanmopar concurred with me, if the fork spring is pulling the fork forward.. which pushes the fork rod tight to the Z bar pivot.. which rotates the Z bar.. which forces the clutch pedal rod tight to z bar and pedal pivots.. then nothing should be rattling.

 

[moparedtn]

Then as oldmanmopar concurred with me, if the fork spring is pulling the fork forward.. which pushes the fork rod tight to the Z bar pivot.. which rotates the Z bar.. which forces the clutch pedal rod tight to z bar and pedal pivots.. then nothing should be rattling.

The clutch pedal rods' hole in the end it attaches to the z-bar on is elongated - slotted - not a tight joint - the clutch pedal can move quite a bit in and out as a result, even with the tightest of linkage beyond it.
I'm not sure where folks aren't getting that....
It has to be in order to allow for drivetrain movement - there has to be a "flex" somewhere in the linkage and the clutch rod end is it.

 

[moparedtn]

 

[dadsbee]

It's still only held by a spring.. it can move if need be. If everything is adjusted correctly and the spring is pulling everything tight then the pivot shaft is against the firewall end of that clutch rods slot. Shouldn't rattle. The slot is there so when you dump the clutch it allows the pedal to come up without immediately pulling the fork rod back harshly.

I'm not sure where folks aren't getting that....

It's you that is asking for help here, not us, and a few of us are trying to help you but you don't want to listen apparently. I've been wrenching mopar since I was 14, a mere 42 years ago and growing. Guess I'll move on and help someone else.