308 clutch lever adjustment

The later cars may be different but for the gt4 and early 308's here is the proceedure

Rob
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wups...robert's post is for the pre-1981 cars that have not been modified. clyde's '83 qv is the newer design that lasted through the end of the 328's.

all the threads talking about 308qv and 328 clutch apply. In short, though, you replace the cable, adjust the clutch lever arm linkage to give the magic 43mm or so spacing as shown in the owners manual, and then adjust the cable to level the clutch pedal with the brake pedal. That's it.

mule did it recently. see
http://ferrarichat.com/forum/showthread.php?t=63166&highlight=clutch+cable

verell suggested using a 43mm wide piece of cardboard as a gauge, and that works really well. Line the edge up as vertically as you can and go with it...it's not that critical.

after that, until you change the clutch, you always adjust the linkage whenever the clutch pedal raises higher than the brake pedal (due to clutch wear)...you never mess with the cable adjuster...well, unless you are compensating for any cable stretch, which I can't recall anyone ever saying they needed to do.

in theory, you can assess clutch wear by how long the adjust turnbuckle-like rod on the bell housing is when the 43mm spacing is accomplished. However, there is no table of values with the answer, and there's enough slop in the measurements to make it a bit impractical.

I think people test the clutch condition by stomping on the gas in higher gears looking for slip. I guess I test the clutch condition in all gears using that technique

 

So then after a clutch replacement the clutch pedal should be adjusted to the same height as the brake pedal? Then as the clutch wears does the pedal rise higher than the brake pedal?

 

Depends.

Older pre-83 308's have 2 springs on the clutch pedal under the dash.

One for return and one to keep it from flinging up under the dash.

Post 83 use only on spring on the return.

regardless, the pedal should be the the same height on pre 83 as the brake pedal and on post 83 it should be the same height or slightly lower.

 

matteo, Will this make it less stiff

 

The stiffness came from #5 in the diagram Rob posted.

That was removed in later years making the clutch looser. Not Honda loose but looser then the original design

 

not sure I understand that description. In the older design, there's one spring that causes the clutch pedal to move away from the floor, and it's stopped by a screw post on a bracket. Pedal height is done by adjusting the screw post position. Free play adjustment (i.e. slack in the cable) is critical to prevent premature clutch wear because the pedal cannot raise higher as the clutch wears.

in the later design, the clutch pedal still has one spring, but it's mounted differently and is now trying to pull the pedal to the floor. The pressure plate is countering the spring via the no-slack clutch cable, and since the pplate is stronger, it wins enough to raise the pedal until a balance is achieved. As the clutch wears, the pplate exerts more force, and the pedal is free to move further away from the floor because there is no stop screw/bracket.

if there's a different design in pre 1978 308's that have more springs at the clutch pedal, I'm not aware of it.

while the spring on the later design is helping to lighten the pedal effort, the pressure plate itself is the main change. The newer plate just takes less force. The difference between the old and new design pedal effort is huge. A lot of people have updated the old design to the new one per a ferrari TSB.

I think spring #5 is rob's picture is trying to lighten the pedal effort on the early design cars, so removing it makes things worse...unless you are changing the design to the later design, but you are supposed to change out the entire arm #1 if you do that.

 

theoretically, yes. As the clutch wears, the right end of the adjusting turnbuckle (#4 in pic above...same on the later clutch design) moves towards the rear of the car, so the turnbuckle needs to be longer to maintain the 43mm spacing.

problem is that nobody has correlated the shift to wear and posted the result. Also, I don't know if the amount of shift in the turnbuckle is linear with respect to the clutch wear due to curvature of the pressure plate release fingers. The '89 manual says that as the clutch wears, less pedal travel is required to disengage the clutch, so that implies a non-linear relationship.

If you decide to swap the clutch, it would be great to know before and after the position of the pin in the right end of the turnbuckle relative to some fixed point, and the thickness of the old/new clutch disc. You have to take the measurements with everything assembled.