1994 clutch issues, sorry for the long post but really need some input

Greetings fellow corvette enthusiasts.  I really need some input from those of you who better understand the mechanics of things.  I bought a 1994 with 16000 original miles on it about a year ago.  The car now has 19000 miles and about two months ago I noticed a grinding sound when the clutch is depressed.  It only happens when the clutch is pushed all the way to the floor.  I can start the car and shift gears at the 1/2 point or 3/4 point without any problems.  Clutch is tight and gears shift smooth.  It's when I go all the way to the floor the grinding starts.  Sounds like the old brake pads would sound if they were worn; metal on metal.  You could even call it a rattling sound.

I noticed a leak and tracing it the best I could it seemed the slave cylinder was the culprit.  So I put in a new one, which is an accomplishment for a non-mechanical type like me.  I bleed the air out per instructions, got a good stiff feel to the clutch, started the car and the grinding was still there when the clutch was pushed to the floor but it was nothing like it was before.  It was barely noticeable.  I took the car around the block and the clutch seemed to stiffen up a bit more.  By the time I got home the grinding was back like it was before I changed the slave.  Absolutely POd beyond belief I put the car in the garage and left it for a few days.

After two days in the garage I started the car.  The clutch felt somewhat looser then before but HALLELUJAH and AMEN!, the grinding was gone.  I figured maybe there was some air left in the system and it worked it's way out while sitting.  Well, you can guess where this is going.  Drove the car around the block and by the time I got home the grinding was back.  Started slowly though, clutch to the floor, no noise.  After half mile - clutch to the floor, think I hear something,  after a mile - clutch to the floor a bit of grinding, barely noticeable,  two miles back to my garage - clutch to the floor, grinding like it was before.  I don't know enough about the mechanics of things to understand where the problem would lie.

I'm asking myself;  Why is it fine if it sits for a day or two and goes bad after driven a few miles?  What's moving too far in the clutch system that's causing the grinding sound?  Should the clutch pedal even be able to go right down to the floor (back of firewall)?  Why does the pedal go all the way to the floor?  How can I stop the pedal from going all the way to the floor?  Does this have something to do with hydraulic pressure?  When the clutch is a little easier to push there's no grinding.  When it stiffens up a bit it grinds.  Since replacing the slave I've noticed no leaking of any kind.  I have no answers and very little hair left to pull out.

I'm looking to trade the car in on a 2010 at a local dealer so I'm trying to spend as little as possible.  I apologize for the length of this post but I wanted to give the details as best I could.  Any thoughts on what the heck's going on would be greatly appreciated.  

you probably have a bad throw out bearing or a clutch cover issue..  this is a pull type clutch..  

the throw out bearing is the tubular device in blue on the left side.. where it connects to the clutch fork.. looks like a sling shot.



use care to not ride the clutch pedal in the 2010...  and you might not have done it in your 94... as to remove the transmission and do the clutch in the 94.. you only have to drop the bracket to the rear end and the drive shaft to drop the transmission to get at the clutch...

on the C5 and C6 models... to get to the clutch on the back of the engine.. you have to drop EVERYTHING under the car including the entire rear suspension and rear wheels..  but its ok.. there is a special jig to assist corvette specialists to get it out in one piece..  

Yup: I think you got that one figured out Wayne...LOL...Sounds like a home run to me...  

The grease in your throw out bearing is a sealed unit, so it won't leak grease on your clutch. I think the grease in that bearing has probably dried up over time. Like your ride a 1994 with all of 19,000. You will have things like this happen the longer the Vette sits. I have a couple cars that sit also, and I'm as guilty as anyone. Here I sit, and I'm going to give you advice I should take myself...LOL...We are all worried someone is going to some bad thing to our rides, so what do we do,LOCK 'EM up and cover them. We need to drive them so the seals stay lubricated, I.E. your throw-out bearing, door window seals, engine seals, etc. etc....I need to go through my 1986 Monte Carlo SS with 55,000 original miles, we are the original owners. The trans and rear main engine seals leak so I am right there with you.

When you shift from 1st to 2nd and don't depress the clutch to the floor does it still make that sound? If not don't push it to the floor, back in my day when we had real clutches, some with as much as 3200 ft.lbs. of holding force. Try to sit at a stop light with your left leg shaking from holding the clutch in so long. Some of us got smart..Hah..Hah..and would pull it out of gear and sit with the trans in nuetral.

The point I'm trying to make is that when we power shifted those trans' and clutches if we pushed the clutch pedal 1/4 of the way to the floor that was a lot...Some guys actually put a 2X4 under the clutch pedal so they push the clutch to the floor.

I'm trying to make light of your problem which it real is, and trading up is up to you. But if your going to trade because of the throw-out bearing don't do it. They would probably catch it on a test drive, when they tell you what it's worth, and probably knock $2,000 off the price for a trade. I would try just using the pedal as far as you really need to shift it. When the throw-out bearing really gets bad it will make a rattleing sound when you have the engine running, and the trans in nuetral. Then as soon as you depress the pedal that rattleing sound will go away.

Today hydraulic clutches are all you see on any new production car.

A quick story my kid brother lives in Port Orange Florida. He purchased new a 2002 Z06 vette with all the bells and whistles.I would go to see him in November,as at Daytona they have what is called Turkey Rod Run. Cars from all over the world are shipped in to be sold.

Anyway he had joined this car club.When I was there the club was actually going to run their cars at Daytona. My brother probably has less mechanical skill as you. So he tells me about what he wanted to do. His Z06 had a video so we could set the car up to run at high speed 140+. It was very specific to the spec we set. He lived 10 miles from Daytona speedway. I told him we have to trailer it there.Everything was cool until we got to the track. There were Ferrari's Lambourgini's Porches, and a few vettes.

We got our turn to run around. I said to my brother hold on this thing needs to run...I used to drive stock cars so the speed was like a shot of adrenilan. 155 MPH. I see a guy with a flagg shaking the flag at me as to he wanted to talk to me..Yeah right..The 3rd lap we were moving along at 170MPH. This Z06 wasn't even breathing hard, I managed to finish at 174MPH...I got to the infield after 3 cool down laps at 90. This thing was soooo smoooth at 170mph I was talking to my brother.I get back and this yutts comes up to me I just kept walking.No-one was to go over 100mph. My brother started having problems with the Vette a couple years later and the cost for repairs on any Vette or HIPO car is high. He sold it last year, and he never told me. I can tell you this he was really surprised that it ran that well. I wasn't all that needed was a cold air intake and it may have gone to 177mph. Atleast he bought the Z06 without T-Tops or a windowed roof, I wouldn't have driven it that hard.  

The problems he was having were mainly electrical and the driver's seat had memory it pushed me against the steering wheel. So if you get a really good deal on your Vette or try selling it on your own....I'm done.Enjoy your ride and have fun because that's what it's all about....

Bob  

Wayne/Bob,

Thank you for the info, diagram, and great story.  From what I've read it seems you both agree that the throw out bearing is the likely candidate.  Which is way out of my league as repairs go.  Guess show room condition and low miles can still equal potential problems.  Like you said Bob, things dry out. I'll have to noodle on this a bit and figure out where I'm going from here.  I think at this point trading it in is out of the question.  Thanks to both of you again.

Frank
(was luvlar then my password failed, the new one the site sent wouldn't work, so I re-registered as luvlar2)