clutch adjustment

1. You absolutely should install a return spring so that the clutch fork does not ride on the throw out bearing, or it will prematurely fail.

2. The adjusting nut on the clutch arm should be adjusted to the point you can just feel play i.e. it is not constantly riding on the throwout bearing.

Definitely install the return spring. Adjust the free play at the slave cylinder adjusting screw to .102". Use a #38 drill (.1015") or a 7/64 drill (.1094").

JB,

I am currently doing this too. Where do you check the play?

Carbo,

Adjustment is at the slave cylinder. Free play is adjusted per the pic on the right. Pic on the left is for the slave cylinder push rod.

Thanks, that looks like what I need.

Carbo

Step-by-step instructions are here at Pantera Place http://www.panteraplace.com/page124.htm

Mike

We just got our 1974 pantera restored and we're having some issues with the clutch setup.

When the car is cold I have no problems shifting through the gears.
I get about 3/8" of movement from the resting position (the space shown in fig. 16 from jb1490's post above) when the clutch pedal is fully depressed.
Once it's running for a bit and hot, I don't seem to get enough travel from the slave cylinder push rod. I'll lose about 1/8" of movement.
Does anyone know what the problem could be here?

Have you checked for air in the clutch hydraulic system? Air in the system will expand when hot and push fluid back into the master cyl res resulting in less movement of the slave piston when the clutch pedal is depressed.

Yea, we've bled the system a few times. Just did so now. We'll take it for a spin now.
I'll post a result shortly.

We bled the system...tiny amount of air, almost nothing.
Took it out for a short cruise, same problem as before.
After it heats up we get less movement at the slave cylinder push rod.

I do notice a good amount of movement in the hose from the master to the slave cylinder.
If the hose is heating up and becoming pliable, could this be causing the loss in movement at the slave?

# 6579 Do you get air out of the system when
you bleed it? Have the clutch master and or
slave cylinders been replaced? Are you bleeding
the system at the master or slave?
Have correct fluid in system?
TOM at T.J.s does great work. Has done
some work on my car as well.
JOHN

quote:

Originally posted by No. 6579:
We bled the system...tiny amount of air, almost nothing.
Took it out for a short cruise, same problem as before.
After it heats up we get less movement at the slave cylinder push rod.

I do notice a good amount of movement in the hose from the master to the slave cylinder.
If the hose is heating up and becoming pliable, could this be causing the loss in movement at the slave?

The line from the master to the slave area is metal with a very hard red plastic section near the slave. Sometimes people replace the red plastic with a braded steel line.

Mike

We bled the system at the slave. I'm not sure how you bleed at the master. There was the slightest amount of air when bled last night.
We're using DOT 3 brake fluid. Both the master and slave are new, from Precision Pro-Formance.

The line from the master is stainless then about a 4 ft section of hose to the slave, not sure what type of hose.
Again, there is a significant amount of movement in the hose when the clutch pedal is depressed.

quote:

not sure what type of hose

Can you post a pic of the hose?

How much free play do you have at the slave cyl when cold?
Does the free play change when hot?

The hose is an Aeroquip FC332-04. 1/4 " hose 250 PSI rating.

We've had some trouble feeling the free play. We've read the adjustment instructions on the pantera place site, but haven't been able to feel any kind of free play. With our current setup it seems almost impossible to move the clutch arm at the tranny by hand.

We've adjusted the slave cylinder push rod shorter and then were able to feel maybe a little bit of play, but then we weren't getting enough movement to fully disengage the clutch.

I suspect that the Aeroquip hose may be the problem. I don't think that the pressure rating is high enough. I'm surprised that whoever installed the ss hard line didn't also install the ss braided flex line to the slave cyl. You can order the ss braided flex line from one of the Pantera vendors or have one made up locally.

As a temporary test, you could get a length (or two) of 1/4" steel brake line from the local auto parts to replace the Aeroquip hose. You will need to change the fittings and reflare the tubing ends. Copper tubing will also work, as this is only temporary.

If the hose is the problem, what PSI rating hose should be used?

I'm not sure what the normal pressure in the system is, but I would guess around 450 to 500 PSI. It depends upon the ratio of the master cyl and slave cyl bores, the pressure plate spring rate, and how quickly you depress (or stomp) the clutch pedal.

The Aeroquip FC332-04 hose has a fair amount of elasticity, has a max 250 PSI rating (you knew that), has a max temp of 300*F, and is not approved for impact hydraulic applications. Stomping the clutch during a fast shift could be construed as an impact application (kind of). If it were my car, I would get rid of the rubber hose and use the ss braided teflon hose. Besides, the ss line looks much better than a hose (even if the hose is blue!?) IMHO.

This all assumes (fatal error) that the clutch master and slave are functioning properly and free of air.

Other possibilities would be if the clutch pedal is not returning fully (broken spring?), the clutch master cyl push rod is too long, or the master cyl is by-passing.

I'll add my two cents. I was having a problem with not enough disengangement, grinding going into reverse and trouble going into first, etc. All this occured when everything was warm. I monkeyed with the slave, bled it, adjusted it, checked free play, etc. Finally, I got fed up with no progress and decided to adjust the eye bolt out far enough that I was sure to get plenty of disengagement. It worked. I now get plenty of disengagement and it still hooks up fine. I am sure I will get flamed for this, but everyone on this forum seems to worry more about "free play" than disengagement. We all seem to be grinding reverse and not shifting correctly in an effort to save the throw-out bearing. I say, go in the opposite direction. Pull the rod out of the slave and give yourself more marging on the disengagement side. The stock rod can be adjusted to give you more than enough disengagement. Just play with it until everything works correctly.

Oh, and the plastic hose comes in handy when bleeding the system. It allows you to see when there are no more air bubbles. Plastics are typically a no no in hydraulics, but in this case there should be no problem. Unlike a braking system, there is no progressively higher pressure in a hydraulic clutch. Once it is to the floor, it won't go any further or generate anymore pressure. The pressure in the system is the minimum amount it takes to disengage the clutch. All the pressure the system will ever see is due to the force generated by the throw out bearing against the clutch fingers. Think about it.