Clutch pedal soft at startup

Read T · 10-30-2014, 09:46 PM

From Ryan, reposted by his permission.

Quote:

I’m very happy to hear you’re enjoying the new pedal assembly!
The feeling of being softer when you first fire it up cold is an adjustment issue causing the master cylinder not to fully return 100%. This causes the balance port in the MC to stop working so when the car cools off the fluid trapped in the high pressure side of the lines contracts causing the pedal to become squishy almost like air in the lines and then after some driving it warms up causing the fluid to expand again making it feel normal.

There are two main causes for this. The first is a common one where the upper cruise control switch is set too tight or wasn’t adjusted after making a change to the clutch rod or AFP settings during tuning. This holds the pedal arm down stopping the master cylinder rod from fully returning. The upper switch should always be the last item adjusted after any other tuning to prevent this. The upper switch should be adjusted so that the black button is just fully depressed but not so much the rubber bumper is hard up against the metal threaded body of the switch.

The second issue can come from over tightening the two side bolts that lock the up/down movement of the sliding center section. If these are over tightened the main pin bearings will be pinched causing the pedal not to fully return to the top or be sluggish. A quick test for this is to press the pedal down by hand and very slowly let it come up with your hand on top just as if you were letting it up with your foot. Note where it stops on its own and then lift the pedal up a bit by hand to see if it stopped short with some travel left. If you could pull it up more by hand (pedal didn’t come fully up to stop on the upper switch) then go in an loosen the lock nuts on the two side bolts a ¼ turn each and retry the test. Do this as needed until the pedal is returning freely on its own, coming to rest against the upper stop.

Hope that helps and let me know how you make out.

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