740 Clutch Creak Woes?

[BearForceOne]

Here's an interesting problem I've been trying to solve for the last few years. I have a 1989 740 Turbo, originally an AW71 car, since swapped to an M46 from a 1986 NA donor 740. Ever since the manual swap, the clutch pedal has felt extremely "creaky", and impossible to smoothly operate through it's full range.

In the swap, I replaced with new:
- Dog dish flywheel, turbo clutch & pressure plate
- release bearing
- clutch cable*
- shifter bushings
- trans mount

All normal contact points were properly lubricated during the swap, I don't believe anything is running "dry".

What I recently learned however, is that only NA 740's received a cable-operated clutch, whereas turbo models had a hydraulic clutch. Along with this change included a different clutch fork that pivots at a different point inside the bellhousing.
Would this difference be the cause of my creaking clutch? Is it possible the hydraulic system provides better force on the heavier pressure plate springs, and leads to a smoother operation over the NA cable system?

M46/7 bellhousing showing difference in pivot locations, the cable system "pulls" the fork/release bearing towards the front of the vehicle where the hydraulic system "pushes" the fork to the rear of the car, pivoting halfway through the fork into the release bearing

Cable clutch fork (top) vs hydraulic clutch fork (bottom, rotated 180 degrees)

 

[dl242gt]

I would start with the clutch cable. The cable operation with a turbo engine isn't a problem. Volvo did that hydraulic setup because it does give a lighter pedal and provides more force easily to the system. But a cable is fine.

You didn't mention what version of clutch cable you installed. If it's one of the aftermarket rubber sheath covered clutch cables. That could already be worn out. Another place that I've heard creaks is the pivot for the clutch pedal. Wurth HHS plus made that go away.

I would start there. Before you get into the big work of taking the trans off.