Clutch grinding when depressed

LUVLAR

MEMBER
1994 CHEVROLET CORVETTE
19,300 MILES

1994 Corvette.

About two weeks ago I was having trouble shifting between gears. Really had to push or pull hard. Checked the trans fluid level at the reservoir on the fire wall and it was way low. Way, way low. Filled it and bought a new diaphragm since the old diaphragm was fully extended and I couldn't "squish" it back to flat. Filling the fluid fixed the problem and everything was fine.

About two weeks later I'm now getting a grinding noise when the clutch is depressed fully to the floor. Doesn't do it at 1/2 or 3/4 pressed. I can shift gears just fine at the 1/2 or 3/4 mark but need the clutch just about fully depressed to start it. That's when I hear the grinding. I'd appreciate any feedback you can give me. Thanks!

Frank

7 Replies

RIVERMIKERAT

MECHANIC
6,110 POSTS

Where is the grinding noise coming from?

It sounds to me as though the clutch arm is rubbing against the clutch pressure plate when the clutch is fully depressed.

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Tuesday, May 29th, 2012 AT 6:55 PM

LUVLAR

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4 POSTS

Mike,

Thanks for the feedback. The noise is definitely coming from the transmission. I can't really narrow it down more than that. I've always loved vettes but I just drive em', don't know what makes em' go. For info or repairs I rely on the pros like you. If it is in fact this clutch arm, what caused it all of a sudden? I've been reading some stuff about replacing trans fluid and bleeding air. Could air in the lines cause this? The car only has 18000 well cared for miles. Thank you!
Frank

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Tuesday, May 29th, 2012 AT 7:24 PM

RIVERMIKERAT

MECHANIC
6,110 POSTS

Air in the lines would not allow the clutch to be fully engaged, so no, it's highly doubtful that would be the problem. Since you say you can shift gears fine even before the clutch pedal hits the floor, that's also another key to me that says no air. What it sounds like is that it needs to be adjusted, that the added fluid and new diaphragm are causing the rod to be moved more than it really needs to be. But, my reference says that nothing is adjustable, which makes me think bent clutch release fork. Take a look at the picture. It shows the main mechanical parts of the clutch. The hydraulic system comprises the clutch master and slave/actuator cylinders. The reservoir is at the master.

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Tuesday, May 29th, 2012 AT 8:07 PM

LUVLAR

MEMBER
4 POSTS

Mike,

Thanks again for your feedback. I somehow feel there's a trip to a mechanic in my future. One thing I've noticed though, the new diaphragm I installed in the reservoir cap looks nothing like the old one. It's, at best, a nipple if you grab hold of it and extend it. The old one extended a good 4 inches. In fact the reason I bought a new one was the old one was fully extended and I couldn't get it back to flat again. Could these tremendous differences between the diaphragms be and issue?

Frank

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Wednesday, May 30th, 2012 AT 12:01 PM

RIVERMIKERAT

MECHANIC
6,110 POSTS

I couldn't be 100% positive without seeing and feeling it for myself, but I doubt it. My reference says your clutch system is self-adjusting. But your description says there is too much deflection in the clutch release fork.