330 GTC Clutch Problem

[67GTC]

I'm experiencing a problem with the clutch on my 67 330 GTC (10539). It's a late hydraulic clutch. After I've been running the car for a half hour or so, the clutch pedal begins to sink to the floor. I can get my foot under it and manually pull it up, and it works fine for a while until it begins sinking again. Clutch fluid level is topped up, and I don't see signs of leakage.

I had the clutch disk, pressure plate, throwout bearing, pilot bearing and hose replaced in December. I called the shop where the work was performed, and they suggested that I adjust the tension on the "helper" spring. I've adjusted this several times and haven't seen any improvement. I'm beginning to think it's a clutch cylinder issue.

Has anyone experienced this problem with their clutch?

Chuck

67GTC

[horner]

If it's not the return spring, and if you are beginning to lose clutch actuation, then it might be that your hydraulic fluid is heating up and losing viscosity. Is there supposed to be a heat shield between the clutch hydraulic line and any heat producing source such as the engine or transmission? If so, check its placement/tightness and adjust as necessary.

Or, if no heat shield originally or currently missing, check routing/clamps of clutch hydraulic line, and if too close to a heat source as above, try rerouting it. I saw this once before on s/n 8939, but this was back in 1988 at a track day and the cause was as above, i.e., the fix was quick by moving the line away from the heat source; I think a clamp came loose. If it will help, I will contact that still same owner for you. Jack Horner

[67GTC]

Thanks for the insight Jack!

Chuck

67GTC

[lukek]

Sounds exactly like the situation with my Alfa Spider. It was a bad clutch master cylinder. It was not leaking per se, but the sealing got worse with the increased heat in the engine bay, causing the pedal to go to the floor.