I finally got around to fixing a few clutch issues today. These are problems I’ve had for a long, long time, but were minor compared to the clutch chatter I finally fixed (replaced slave cylinder) so they‘ve been let go far too long.

Problem 1

I’ve had clicking for a long time when letting out the clutch. This was due to the clutch fork hitting the floor when taking off in 1st gear. I’m not quite sure what causes the fork to vibrate, but I suspect it’s normal enough considering I use a 3-finger pressure plate plus the clutch fork pivots on an L-bracket, not a ball.

Turns out the last time I installed the engine it didn’t sit quite as level as it should and the clutch fork side was a bit high and closer to the floor. So I jacked up the front of the car, placed a couple of axle stands under the frame and went to work loosening the engine mounts.

To lower the side I used a jack and a piece of rod to jack the engine up a bit on the opposite side. I then used a pry bar to wiggle the engine rubber mount away from the frame mount on the side I wanted to lower.

Worked very well, but I had to repeat a mirror image of the procedure as I over-did it the first time and it dropped too much.

Problem 2

The other issue was that I sometimes experienced a bang or clunk when letting out the clutch. This was more likely to happen when starting up a hill from a stop where engaging the clutch takes a little bit longer.

I suspected the clutch master cylinder. I had replaced a leaky slave cylinder a while back due to internal corrosion. I blame it on using DOT 5 which was the recommended stuff when I built my car. Water doesn’t mix with it and settles in the lowest part of the system, the slave cylinder.

I suspected that some moisture may have caused a similar problem in the master cylinder, where it may have gotten trapped at, or near, the idle position of the piston seal. My thinking was that as I let out the clutch pedal, I would reach a point where the master cylinder seal would suddenly yield pressure and the clutch would sort of pop into it’s fully engaged position regardless of my foot still being on the pedal a bit. So I shortened the rod between the slave and the clutch fork so the master cylinder seal would be operating in a different part of the cylinder.

Results

I went for a test drive and the clicking was completely gone! I did quite a bit more starting and stopping to ensure the clunking was also gone. It was fine and although I can drive it this was for a while, what it really showed me was that I need to replace the master cylinder.

Overall, a successful day.