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Discussion Starter #1
The hydraulic clutch install on my 73 mustang went over as planned and all the components went on without a hitch. The problem I am facing however is the same problem as before when I attempted a cable install. There is not enough displacement of the clutch fork (7/8 of an inch is way less than the 1.25 needed). I initially bled the system but I thought I'd do it again to make sure that was not the problem. That didn't help any with the clutch fork but I did manage to fill my ear with brake fluid.

I think that I should have gone with a larger master cylinder on my application so that the amount of displacement on the push rod in the master cylinder would not have to be so great. I did not think about that when I ordered my parts but I am wishing I had.

I plan to move the arm on my linkage down further to get more displacement out of the master cylinder but there is unfortunately a limit to how far I can go down on the clutch pedal before the angles get to out of whack.

Have any of you guys had problems like this? Let me know what you think.

http://webpages.acs.ttu.edu/jikelly/master.JPG Master Cylinder

http://webpages.acs.ttu.edu/jikelly/Pedal with leaver.jpg Clutch Pedal with linkage

[IMG]http://webpages.acs.ttu.edu/jikelly/slave 1.JPG/image]
Slave Cylinder
http://webpages.acs.ttu.edu/jikelly/slave2.JPG[/IMG]
 

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I might have some good news for you that initially foiled my attempt. For starters, you need to make sure that you are using a 3/4" master and 7/8" slave. Secondly, you need to ensure that you placed the pushrod for the slave at the inner hole rather than the outer hole on your clutch fork. Most importantly, however, is the clutch pedal travel. When I initially set mine up, I depressed the clutch what I thought to be fully, and the slave pushrod only moved a half inch or so. You need to really step on the pedal to make sure that you are fully engaging the master cylinder. It takes a lot more effort than you might imagine. It goes down smoothly at first, but the last part of that 1.125" takes a little more effort. Try that to make sure that isn't your problem. Report your findings on the forum (in this post) or feel free to pm or email me. I'm happy to help.

Jeff
 

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Sorry, I didn't see the bottom pic before my previous post. Did you also turn the nut on the pushrod out until it put some pressure on the fingers of the diaphragm? The throw-out bearing needs to be resting firmly against the diaphragm. Also, I noticed that you used a clever horseshoe design. It seems that you used two bolts for stability on one mounting point, but I only see one bolt on the other. Is there any chance that the setup is flexing? The last thing I can think of is that you need to make sure that you are actuating the master pushrod along the same axis as the piston inside of it. I first noticed on mine that I was about 1/8" high of the axis of the pushrod and this caused me to be able to depress the pedal, but it forced the pedal to stop before it reached its full stroke (it felt like it was supposed to stop at this point when it really wasn't). Sorry for all the checking-up...I'm just trying to cover some of the hindrances that I encountered along the way. Just let me know ;).

Jeff
 
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Well the way it works on my car is the pushrod in the master cylinder is attached to a bolt and the bolt goes into the hole you see on the arm on the clutch pedal. The arm swings so I was sure to make the hole large enough to allow the pushrod to start out below center (angled down slightly) and end up above center. I don't think that the pushrod is binding on the master cylinder but I will check it again.

I put some washers in between the arm and the rectangle bar with the hole for the bolt. That allowed me to get more displacement out of the arm on the pedal and push the push rod into the master cylinder farther. That is the theory anyway. I need to go back to the hardware store and get a longer bolt to extend the pushrod a little more so it can reach the arm.

By the way should the pushrod always start all the way out of the master cylinder on each stroke, or should it be pushed in the cylinder a little? In fact how far does the pushrod have to go into the master cylinder to displace enough fluid to completely extend the slave cylinder?

As far as the slave goes there is another bolt that you can't see in the picture that attaches a brace from the rear tranny tab (bolt hole) to the C bracket. Wait unless you mean the bottom where the C bracket is attached to a square piece, which is attached to the bell housing. I have not seen any flexing in the bracket that holds the slave so I think maybe I finally did something right for a change. There are more pictures on the website I'm building where you can more clearly see some of the setup.
http://webpages.acs.ttu.edu/jikelly/pictures.htm

Thank you for all your thoughts and suggestions.

Jimmy
 

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I have my pushrod setup so it is completely extended at the master. I will take some measurements sometime tomorrow (either before or after work) and let you know how far the pushrod travels to attain the 1.125" of travel at the fork. If you need anything else, feel free to drop a line.

Jeff

p.s. before I forget, did you add a spring to the slave to return it to its original position?
 
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Hum... Your last question about the spring makes me wonder something. I guess the master cylinder alows fluid to be returned from the slave after the push rod it backed all the way out. If you didn't have a spring on the slave then would some fluid be left in it and the slave be pushed farther on the next pump stroke of the master? I can see how it would be bad if that happened and the slave was pushed past its seals.
 

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That is a highly possible factor to consider. Usually, however, the internal pressure created by the system is enough to pull the slave most of the way back to its original position. The spring is used for the final few thousands of an inch (in my case at least).

Jeff
 

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You may have a air in the line. You need to think like a buble, where would I get stuck? Here is the method I used to get the air out of my system. I unscrewed the reservoir cap and pushed the slave cylinder all the way in. We actually saw the bubbles in the reservoir. Once we got all the air out, we started bleeding the system, the same way you bleed brakes, until we had a full 1.5" of travel. You want to set the MC so that there is about 1/8" of play when you push the pedal in. Otherwise, the throw-out bearing could actually end up riding on the clutch and lead to pre-mature failure.

Sorry I can't help much with your custom setup, as I bought the JMC kit. Best of luck.
 
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