randyhenry

I have a 2000 z28 with just bolt ons. Had the sticking clutch problem so I did the drill mod, replaced the master and slave and put a new centerforce dual friction in. I used dot 4 synthetic fluid and have bled it a dozen times. The petal doesn't stick anymore but I can't shift the car hard. Even at idle it is hard to get in gear. In every single gear. Centerforce says I shouldn't need a shim behind the slave either. I'm getting so frustrated here. Any help would be great!

SPEC-01

iTrader: (2)

Because your issue affects every gear it is pretty safe to assume that this issue is relative to release. This can result from air in the hydraulic system but, because the slave and master are new and the pedal is consistent I think we can proceed as though this isn't the root cause.

It is possible that this is relative to several factors other than hydraulics and I will outline these below:

A bent clutch disc can cause issues with release and generally results from hanging the transmission off the shaft during installation. This isn't the most common of things to occur, especially when using a transmission jack, but it is possible.

A damaged pressure-plate, perhaps one that was impacted by the input shaft during install, could also lead to release issues. This is less likely than the bent disc, but it can happen. You could also have a plate with a damaged pivot, but I would assume that your clutch provider checks each plate for function before shipping.

Improper torque on the pressure-plate to flywheel bolts would allow the plate to lift away from the flywheel when the diaphragm was compressed by the bearing...which would certainly affect the way the clutch releases.

Lastly, an overly thick disc, or miss-machined pressure-plate could affect release too, as they wouldn't provide the needed air-gap or pull-down required for proper function.

Though I hope the above info has helped, I think you ought to give the guys at centerforce a call for their input. Please let me know if you have any further questions and I will be happy to assist you further. Thanks!

randyhenry

Would this gradually get worse though? Right when I changed it I went to the drag strip and ran a 13.6 spinning the tires. I tried slipping it to hook up my last run and it seems to be worse after. The clutch does not slip at all just hard to switch gears. I'm not sure if I used dextron 3 in the tranny either? It might have just been atf but would that maybe cause this? I've put a couple hundred miles on it since then with no change. I'm confused!

Gen414

iTrader: (38)

Well, a "gradual" increase in difficulty could be "heat soak" in teh MC/Slave line. Does it happen under normal driving, or are you experiencing this under speed shifting? If it happens all the time, under all driving conditions, I doubt it is "heat soak". BUT, if it only happens when you try to speed shift, then I would say that and/or not enough fluid volume from teh stock MC, and the only cure there is teh drill mod (band aid which you already did) or an aftermarket MC

Also, the wrong fluid can cause difficulty in shifting.

randyhenry

It seems to be there right when I start it up after sitting for a long time so I'm doubting it's heat soak. When I push the clutch in my MC or the petal makes a creaking noise also, I don't remember my old one doing that. I think the whole stock hydraulic system is bogus. Seems a lil worse when speed shifting though. I'm going to try changing the tranny fluid tonight for starters then go from there. U think a aftermarket MC would help or should I pull the tranny back out and check things out? After the fluid change of course.

SPEC-01

iTrader: (2)

An aftermarket MC couldn't hurt...but it may not be the culprit. That being said it is a whole lot easier to replace the master than pull the trans. I say throw a MC in it and see if that changes anything. You may also want to check the fluid level in the transmission as well. If its low it is going to affect every shift no matter the temperature. Let us know what you find. Thanks!

randyhenry

I just changed the fluid and there was no noticeable change in shifting yet. I will drive it to work tomorrow and see for sure. I also put a short throw shifter in when did the clutch. Could it just be I'm not used to it? Didn't think that would make that much of a difference?

Gen414

iTrader: (38)

Well, the shifter could have an affect on your shifting, and not being used to it, sure. What is the "level" that you are adding to? Are you filling through teh shifter, or teh "fill" hole? If the fill hole, you add until it starts running out, right?

After you have checked all that, and you are sure system is bled correctly, and problem is still there, I would do a MC first since it the easiest (I like easy ) and go from there...


Also, do you have the "stops" on your shifter? What kind is it? If you have the stops adjusted wrong, that COULD be your problem....

randyhenry

It's actually a stock shifter just with a shorter stick, so it's not that part. I checked the plastic bushing and the shifter out it was all good. I fill the trans through the shifter and just take the fill plug out, fill till it starts to run out. I just bled it again two days ago so I'm doubting that. I use the mighty vac and then bled it manually too.

SPEC-01

iTrader: (2)

It seems that you have done all the basic checks...now all that is left is to either pull the assembly, or replace the hydraulics (beginning with the Master and proceeding from there). If you decide to pull the transmission remember that the guys from tick provide a great deal of information relative to the need for shimming. I have provided a link to their thread and it would be worth checking the measurements of your assembly to insure that everything is copasetic.

https://ls1tech.com/forums/manual-tr...need-shim.html

randyhenry

Thanks a ton for your help! I might be pulling the tranny to check this weekend. Should I try reusing my old MC or just get another new one? I got mine from an auto parts store, might not be as good as the gm one? It just really sucks to have to buy more new parts when I already have around $600 in this setup and have only driven a couple hundred miles. I'm determined to get it right though. Never had any of these problems with my LT1 cars.

SPEC-01

iTrader: (2)

As long as the MC is functioning it doesn't matter where is came from. Of course, it has to be functioing properly and thus able to apply the appropriate pressure needed to release the clutch. Try the one you have and go from there.

randyhenry

Well I haven't tried changing the MC yet because my old one is at my uncles house 2 and a 1/2 hours away. I noticed yesterday that if I pump the clutch before shifting it goes in perfectly. I have to pump even between shifts though too, leading me to believe it is the hydraulics for sure. Maybe I'm just not bleeding it correctly? Idk?

SPEC-01

iTrader: (2)

If you have to pump the pedal to shift then this is definitely hydraulic. Either you have air in the lines or you have a bad slave or master. But, the only way to tell whether its the slave or master, if neither is evidencing leakage, is to replace them one at a time and proceed as needed.