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auzziez

Question about Clutch Fork throw???

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    I realize that this is one of those posts that is probably going to generate more questions than answers.

    I have an S30 with a 5-speed transmission. What I am trying to determine is the distance that the Clutch fork should move when the clutch is pushed in. I don't have any info on the tranny other than from the pictures that I am attaching here.

    The problem that I am having is that the clutch is not disengaging the transmission. I measure the throw on the fork and it only moves 11mm, which looks to be only about have the distance that it could travel.

    I understand that there are numbers on the top of the bell housing that would tell me the exact tranny model, but I want to hold off on dropping, unless it is absolutely necessary.

    Any help would be appreciated.

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    Edited by auzziez
    adjust pics

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    Blue just gave a number in this thread - http://www.classiczcars.com/forums/showthread.php?t=47300&p=410213#post410213

    The numbers on the bell housing won't tell you much, and won't have much to do with how your clutch works. It's the combination of pressure plate and throwout bearing collar that matters. Tell some details about what clutch package you started with and any changes you made when you put the new transmission in.

    The transmission looks like a 77-79 "early" "wide ratio" 5 speed, by the way.

    I see that you have the adjustable rod from the slave cylinder. Have you tried extending it yet?

    Edited by Zed Head

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    Im very interested in this topic as im about to change 77 5 speed to my -72 240z. I have Exedy (made in Japan) clutch kit. I noticed that the 77 tranny has fill plug on the other side.

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    The problem that I am having is that the clutch is not disengaging the transmission. I measure the throw on the fork and it only moves 11mm, which looks to be only about have the distance that it could travel.

    When is it not disengaging? If it is at start up - that you can't put it in gear - then the clutch may be fine - but the clutch disk is rusted to the flywheel - that happens in Florida when the car isn't driven for a few months.

    If the car starts - you can put it in gear and drive it - but the gears grind when you shift - then it could be a problem with the clutch master or slave.

    That is a 77-79 5spd - and it was professionally rebuilt a few months before you bought it. {John Williams in Atlanta}.

    FWIW,

    Carl B.

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    thanks for the replies so far, the real problem that I am having is with the car in gear and clutch pressed in the car will lurchforward when I turn the key. if I take the car out of gear, it will start no problem, but won't shift into gear without grinding. the clutch fork will move 11 millimeters so there's pressure in the hydraulic system. any ideas on how best to troubleshoot this, thoughts?

    Edited by auzziez

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    Do you have a good idea of how the clutch works? You haven't responded to Posts 2 and 4 and you're asking the same question over again.

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    You didn't give any details about the clutch parts that are in the car. Are they the 240Z parts or did you install a 280Z clutch to match the 280Z transmission?

    Actually, extending the rod probably won't help. If the rod was too short, the slave cylinder piston would just pop put, unless the rubber boot is retracting it when you release pressure. I would loosen the rod adjustment nuts, push the rod back in to the slave cylinder, and re-tighten.

    The other possibility is your pressure plate and collar combination.

    Edited...

    Edited by Zed Head

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    You didn't give any details about the clutch parts that are in the car. Are they the 240Z parts or did you install a 280Z clutch to match the 280Z transmission?

    Actually, extending the rod probably won't help. If the rod was too short, the slave cylinder piston would just pop put, unless the rubber boot is retracting it when you release pressure. I would loosen the rod adjustment nuts, push the rod back in to the slave cylinder, and re-tighten.

    The other possibility is your pressure plate and collar combination.

    Edited...

    Got It! I wish I could provide that information, unfortunately, the tranny/clutch combination were in the car when I bought it, and the tranny has never been off of the car.

    I'm going to start with the obvious work that I feel comfortable doing myself. If it comes to dropping the tranny, I'll have to take it to a really good tranny shop nearby that has worked on my Supra Turbo.

    I'll refer to Blue's thread since that looks like very relevant information.

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    I went back to your first post and realized it's not clear if the clutch has ever worked. I kind of assumed that you had put the 5 speed in and were having problems.

    The first thing that I would do is remove the rubber boot on the slave cylinder and see if there is brake fluid inside (brake fluid is used for the clutch hydraulics). If there's fluid inside, you need a new slave cylinder. It's common to get some, but not all, of the stroke when the cylinder starts to go bad.

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    thanks for the replies so far, the real problem that I am having is with the car in gear and clutch pressed in the car will lurchforward when I turn the key. if I take the car out of gear, it will start no problem, but won't shift into gear without grinding. the clutch fork will move 11 millimeters so there's pressure in the hydraulic system. any ideas on how best to troubleshoot this, thoughts?

    Sound like the clutch disk is rusted to the flywheel. We had a discussion here a few weeks back about how to break it free.

    You have to roll the car out on a street with no real traffic. Start the car and let it warm up so it is running fine, then shut it down, then put it in 1st gear. You have to get the car rolling in gear - by starting it in gear and letting it roll forward with a little throttle at about 20mph. Then you have to stop the rear wheels from turning while at the same time you hold the clutch pedal to the floor and apply more throttle. You stop the rear wheels from turning by using the E-Brake. You yank it up HARD. You may have to repeat that process a few times.

    FWIW,

    Carl B.

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    Siding this conversation: does the -72 240z clutch slave cylinder work on -77 5 speed?

    I will be able to let you know in a few days. I just ordered the clutch slave from Motorsport Auto. According the they guy I spoke with, it should fit just fine since I already have the clutch fork with the hole in it. This version of the clutch slave is adjustable. Later versions are not and have a solid clutch folk. I'll post the results of the parts swap once I am done.

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    This sounds familiar. I haven't had a chance to revisit mine yet, but after replacing the master cylinder (along with everything else), I think my clutch MC just isn't extended far enough to the pedal. Good luck

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    Got It! I wish I could provide that information, unfortunately, the tranny/clutch combination were in the car when I bought it, and the tranny has never been off of the car

    A 77/78 5spd which was freshly rebuilt by John Williams in Atlanta was installed with a new Clutch Assembly - about six months before Toyy bought the car from my son. It ran, drove and shifted as it should - all the components are correct. As I recall Tony has owned the car for what.. three or four years now. In that time I doubt he has put more than a few thousand miles on it. Look at how clean the tranny still looks in the pictures he posted. I don't see any signs of the slave leaking. As I recall the clutch system was filled with DOT 5 by the way.

    FWIW,

    Carl B.

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    Siding this conversation: does the -72 240z clutch slave cylinder work on -77 5 speed?

    The answer is YES. The 72 Z's used the Type B tranny - Same as the 77 5spd. They both used the same Self Adjusting Slave Cylinder. They both use the same throw-out bearing fork - with NO hole in it.

    Of course you can use the 70/71 style Manually Adjustible Slave with the correct Fork - on any of the transmissions.

    FWIW,

    Carl B.

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    The parts arrived from Motorsports Auto in just 4 days! Let the fun begin. Damn I wish I had a lift!

    On a side note. The DOT5 fluid in the master reservoir is a bit brown, and since I am replacing everything I would like to clean out the hard hydraulic line. I searched the forums, but didn't see any discussions about this.

    How Would You Do It?

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    Let the fluid drain out at the slave Before You Change It. Take a clean rag and clean out the reservoir. Install the new slave. Then refill the resevoir and let clean fluid drain though the lines to the slave. I ususally let a cup or so drain though. Let it gravity bleed - keep the resevoir full - so you don't introduce air pockets in the line. Just put a catch pan under the slave and leave the bleed valve open. After you have put a cup or so though - close the bleed valve.

    FWIW,

    Carl B

    Edited by Carl Beck

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    Survey Says!

    So the effort of changing the Clutch Master and Slaves was well worth it, although the actual problem was exactly what Carl said it would be.

    Firstly, the parts order from MotorSports Auto came quickly and at a reasonably good price. All parts were as expected, in new condition, and as ordered.

    Parts removal went in the following order:

    Remove the clip from the line connector where the hydraulic hard line meets the slave cylinder rubber line.

    Disconnect the two lines at the connector and let drain.

    Remove the Slave cylinder bolts and remove the slave from the tranny.

    Disconnect the Master cylinder from the clutch pedal (easier said than done).

    Disconnect the Master cylinder hard line

    Remove the Master cylinder nuts and washers and remove the master from the firewall.

    Installation was mostly the reverse. Make sure to connect the Slave cylinder rubber line to the slave cylinder before reinstalling the slave.

    Before connecting the Slave cylinder hard line to the slave cylinder rubber line, follow Carl's instructions to flush out the hard line. Amazing how much crap came out of the line.

    I reconnected the hard and rubber hydraulic lines and let the slave cylinder gravity bleed before actually performing a push-pedal bleed with the help of my wife.

    Problem was that after all of that, with almost 5cm movement on the clutch fork, the car still leaped forward when I tried to start it. This meant that the clutch and flywheel had somehow frozen together, which seemed impossible since I had driven and parked it just 1 1/2 hours before this problem first happened.

    In any event, I put the car into 4th gear and with the help of my next door neighbor, we pushed the car forward and backward 4-5 times. We were able to skid the wheels in my garage. I then got back in, with the car in gear and the clutch in, I turned the key and although it leapt forward, we heard a small "clunk". Next time I turned the key, it started right up with the clutch pedal in.

    I immediately took it out for a run. I need to adjust the clutch pedal a little bit, but I think the problem is solved. Lesson learned: Drive it at least once a week during the humid Florida summer time.

    Thanks for everyone's help on the forum.

    Edited by auzziez

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    Good to hear you got it worked out. Now - peel some rubber, do some power shifts about 5000 RPM.. the harder you run a 240Z the better they run. That will also clear most of the corrosion off the clutch disc and flywheel surface.

    Normally this doesn't happen unless the car has sat for several weeks or months. If it happended just 1 1/2 hours after you parked it - that is really rare. Must have been a very short trip - just enough to warn things up, but not enough to clean the disc/flywheel.

    Anyway - we are starting to get some mornings and evenings cool enough to drive a 240Z here again..

    FWIW,

    Carl B.

    Edited by Carl Beck

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