clutch pedal/cable adjustment???

redridge · 01-07-2014, 01:21 PM

My clutch pedal is way to high. Im finding it difficult to rev match since the travel is long. Im gonna adjust the pedal to a shorter stroke. My question is, do I need to adjust the clutch cable as well or is this an independent system. Thanks in advance...

pete3799 · pete3799's Garage

Year?

Jdub · 01-07-2014, 02:15 PM

Great question. I performed the adjustment at the transmission in my SC and always assumed wherever the pedal sat - that is what I had to deal with. John Walker had my car and readjusted the pedal to a much better (easier, more comfortable) height - but is this something done at the trans, or at the pedal?

So same question from me - how is the pedal height from floor adjusted such that you continue to retain the correct adjustment at the transmission?

javadog · 01-07-2014, 03:12 PM

The resting position of the pedal is not related to the cable adjustment. You also can't change the stroke at the pedal without essentially screwing up the release travel at the other end.

Get used to the position and travel... It's fine once you get used to it.

JR

redridge · 01-07-2014, 04:53 PM

car is an 1986

I know there is an adjustment bar for the pedal,

I can change gear w/o bottoming out the clutch pedal (no grinding or riding the clutch) so I really want the clutch closer to the floor.

So... if I change the clutch pedal travel, I have to adjust everything downstream?

javadog · 01-07-2014, 05:14 PM

Have a close look at the pedal cluster and get back to me.

JR

Jack Stands · Jack Stands's Garage

If it's a 915 transmission, the engagement point can be adjusted. My car had a very low engagement, and it was adjusted in just a few minutes with me in the car and the technician under the car while it was up on the lift. I understand he adjusted the position of the cable housing where it attaches under the differential.

Works much better now as it's the same as my other car's clutch engagement points!

scarceller · scarceller's Garage

Our host Wayne has this written up here:
Pelican Technical Article: Clutch Adjustment - 911 (1965-86) - 930 Turbo (1975-86)

redridge · 01-08-2014, 05:32 AM

thanks for that... I figured worst case, when I adjust the clutch pedal, I would also do the cable adjustment if needed.

scarceller · scarceller's Garage

When I purchased my 84 911 my clutch was engaging very low near the floor, I followed that article's procedure and problem fixed. The real issues was not the pedal adjustment, it was at the rear of the cable, it was totally out of adjustment. It's very easy to work at that end (rear) of the cable, I suggest you adjust and verify that end first.

Quote:

Originally Posted by redridge

thanks for that... I figured worst case, when I adjust the clutch pedal, I would also do the cable adjustment if needed.

javadog · 01-08-2014, 05:46 AM

If you look at the release mechanism, you have a helper spring at both ends. There is an over-center effect from the one at the pedal. It is designed to pull the pedal back against a non-adjustable stop in the cluster. If you adjust the cable incorrectly, the pedal will not return all of the way.

At the other end, the omega-shaped spring also has an over-center effect and you have to be careful how you adjust the cable. Have a look at how it works and see if you really want to change that geometry much.

I don't know how much travel is needed to completely disengage the clutch (Porsches specifies 25 mm on a 911 and 27mm on a 930) but I suspect there's not a huge amount of extra travel available at the pedal end with the floor stop adjusted all the way to it's limits.

I'm not sure what you mean by your difficulty in "rev-matching" anyway. The amount of travel needed to release the clutch is the same no matter where the release point occurs in the pedal travel. To change the travel you'd have to change the mechanical advantage of the system at one end or the other. All you guys are doing is lowering the engagement point closer to the floor.

JR