I have a 93LT1 coupe with the 6 spd manual. It is hard to get into first and especially reverse some times without really cranking on it. Occasionally (today) it would even give trouble going into the other gears. It seems to be somewhat random, but often enough it is starting to bother me. If anything when its hot, it does it seems to help. Also, if I am moving (rolling down a hill) it shifts pretty easy, like I would think it should feel. It never grinds, it just doesnt want to go in like something is misaligned, binding, or blocking the shifter. I know this subject has been brough up before, but I cannot seem to find the correct combo of search terms for it. I am just wondering what are things that cause this and what can I do to narrow it down and if it is worth fixing or if I should just deal with it.

 

The clutch probably isn't releasing all the way. Have you checked the fluid level in the clutch master cylinder reservoir (under the ECM)?

 

I agree.... 99% of the time the clutch not releasing all the way is the problem.

Check you clutch master fluid level and check under the car at the clutch slave cyl and lines for leaks.
Will

 

...and it's likely putting more wear on the synchros, so get it fixed asap.

 

Thanks, will look. Hopefully it is something that stupid. I just topped it off a couple weeks ago when I took it out of storage though.

 

If you had to top it off, it's leaking. It's a closed system.

Fluid can leak from a faulty slave cylinder into the bell housing and not touch the ground so you might not even see a wet spot on the floor.

 

Well, it wasn't empty, it was halfway between "full" and "add", just the normal make sure everything is full for the season top off. I just checked it and it is still full. I had the slave replaced last year and may or may not have had the fluid all the way to the top, I dont remember. Usually I do the work myself, but I had to have an inspection anyway and did'nt feel like spending the afternoon on my back. When it was leaking from the slave, I was having to fill the reservoir every week. It doesnt look like it has lost any since I topped off. I think it is safe to say the fluid is good. It moves freely with the car not running, so I doubt is any kind of linkage binding. Is there an adjustment they may have missed when doing the slave?

 

No adjustment.

Pull the drive shaft off the diff. Engine off, have someone depress the clutch all the way, put it in 6th gear, and you try to turn the drive shaft. You should be able to turn it very easily. If you can't clutch isn't releasing.

 

When I bought my car, po told me that he had just replaced the clutch and slave. Clutch slipped like crazy. Found out he replaced the slave with a new leaking unit that sprayed oil all over the clutch disk.

New clutch slaves/masters can leak right out of the box - your symptoms all point to a hydraulic seal failure.

If/when you replace the slave, replace the master as well. Any contaminants that destroyed your slave have probably damaged your master as well.

 

Even though it is a closed system you will have to add fluid over time (just like brake fluid) due to clutch wear.

If your fluid is good, I'd look at the master and slave cylinder. Even if you aren't seeing evidence of leakage around them they could leak internally affecting your system. If you have the stock clutch, the slave is accessible without dropping the transmission.

 

This is incorrect. You should not have to add fluid due to clutch wear. There is enough capacity in the master reservoir to accommodate clutch wear.

[QUOTE=jwheelerjr;1586857681]Even though it is a closed system you will have to add fluid over time (just like brake fluid) due to clutch wear.

QUOTE]

 

I second the notion that a new master or slave cylinder can leak. My 93 had a bad second gear synchro caused (in my opinion) by a bad replacement slave cylinder.
I read up on it and it turns out that a rebuilder hired a guy who put the cylinder seals in backwards because it made them easier to install!! So a lot of 'bad' rebuilt slave cylinders got sold because some idiot didn't understand that the seals were hard to install because they were meant to 'SEAL' the fluid in.
I replaced my slave cylinder and it improved my shifting. I still ended up replacing the ZF transmission though.

Hope this might shed some light on your situation.

 

Well, I am confused. I really dont think it is leaking anymore, I am going to just keep an eye on it now that I know for a fact that I filled it. The car has done this a lot since I bought it, is it possible that the synchros were already messed up? I have no idea how long it was driven with a leaking slave and it even took me a while to figure it out. My only experience with bad synchros was an old VW and it would grind everytime I shifted to 2nd, the corvette just doesnt want to let you in, but no grinding. Also, I put it on flat ground and in first and reverse with the clutch depressed it was not moving, which would have been an obvious sign of a problem if I was still being pulled with the clutch depressed.

Is it possible that they did not do a good job bleeding it? Isn't this a self bleeding system?

Tom400CFI is there a way to do that test without taking the drive shaft out? Couldnt I just do the same by turning the rear wheel or is there a leverage/friction problem doing it that way?

 

Just read up on ZFdoc website about this issue, http://www.zfdoc.com/techinfo.htm (down in clutch section) I wonder if this is whats going on? Did you actually confirm it or did you just go ahead and replace the slave?

 

Yes, you could try it w/the rear wheels. That was good thinking.

If it didn't have a synchronized reverse it would be easy to test: clutch in engine running, see if it grinds going into reverse (means the clutch hasn't fully disengaged)....but since every gear is synchronized we can't do that test. Taking what you said, one step further, I wonder if you could simply raise the rear, start engine in gear, clutch in and see if the clutch is dragging enough to turn the rear wheels. It shouldn't...

 

So I have not had time to jack up the rear yet and check the engagement/disengagement, but I have been trying to time my shifting and it shifts a lot better. If I sit on the clutch for even a second or two, it gets hard. So, I think that I either have a crappy slave in there or maybe a leak. Fluid level is holding steady so far so probably the slave issue that ZFDoc did a write up on. Anyone have any recommendations on where to get quality slave/master cylinders? I also saw that it is recommended to replace the master/slave as a set.

 

You guys were all right, my Master cylinder was leaking. Started leaking pretty noticably about two weeks ago. I just got done replacing it and now my car wont start I pulled it into the garage no problem a couple hours ago. Lights come on, but no crank. Is there an adjustment to the clutch position switch? Could I have messed something else up? The pedal used to go all the way to the floor before and now it is hard as a rock. What is it supposed to feel like? I am starting to wonder if I have been driving with a messed up CHS the whole time....

 

I can say with about 99% certainty it's the switch on the clutch pedal that when you press the clutch down it completes the circuit so it will start.
It's the one way up by the pivot on the clutch pedal. There's a 2d one that's lower down, assuming you have cruise control - that's not the one.

I know this because I had the same thing. Unplug the pigtail from the upper one and jumper it (the wire that is) and it should start. Be sure though you understand that you can start the car in gear, whether or not the clutch is depressed. Thing is, I'm not sure that switch is even available any more except used.

Hope that helps.

Paul

 

I found it and jumpered it, car started. I think something else is screwed up though. I can't shift at all now with the car running where as before it was difficult but would at least go it I timed it right. It feels really hard and will not go to the floor, I cannot see any obstructions. Is it possible to screw up the slave installation, that went in pretty tough? Am I supposed to be able to put the pedal all the way to the floor? It took a while to get all or most of the air out with the bleed screw on top, I thought it was all out so I installed the slave right side up and went up and started with the pedal, it was soft at first and took some more fluid, then it got really hard. What am I missing?

 

Sounds like you're mimicking what I went through on my 86. Once the master and slave were swapped out, then the switch problems then couldn't get it into gear while running.
I found if I pumped the clutch several times, it shifted fine - meaning there was still air in the line. My mechanic had worked many hours on it but without success on getting 100% of the air out. I took over and eventually got it out. Here's what I did:
I found a Youtube that showed someone using a tip from a brake kit along with some plastic hose to first draw out some fluid through the hole in the bottom of the master cylinder, then force it back in (being careful not to introduce more air) and got some air out. Unfortunately it wasn't all of it.
I work with a guy that's a former GM mechanic and he said he'd worked on quite a few hydraulic clutches and had a trick to try. Air collects in the bend in the line above the master cylinder. The trick is to pump the clutch 5 or 6 times and hold it to the floor for around 5 minutes to any air in the line will work back into that curve. After 5 minutes, slip your foot off the clutch and let it pop back on it's own. I did it twice and at the end all the air had come out of the line.
I did this last September and it's been working fine ever since.

Hope that helps. Good luck.