Next hydraulic clutch problem... clutch not disengaging

[67greengt]

Hello again...

More hydraulic clutch probs

Well I was able to get the slave bled after extensive bleeding, I finally realized how to do it with a pop bottle filled with brake fluid, hooked up to the bleeder screw.

Now it seems as tho I'm not getting enough travel on the slave to fully disengage the clutch. I'm getting about 1" of travel at the slave? Does this sound right? When its in gear with the clutch in and when I bump it over it's trying to go in w/e direction I've got it in. Also, when in neutral with the clutch in I cannot get it into gear...

Here's what I'm using

CNC 711 - 3/4" master
CNC 305B 7/8" slave
Lakewood Bell 15202
Lakewood Clutch fork 15525
Centerforce N1439
Centerforce Dual Friction clutch DF700000
Mcleod Dual surface Clutch Disc
Tremec TKO-600 tranny

I'm not sure what the problem is but I've tried everything, all to no avail. I took the tranny back out and adjusted the pivot stud in the the scattershield. I've made it as long as possible and it just doesn't seem to be getting enough.

From the research that I've done it seems as tho I've got all my bases covered for parts etc???

Thanks
Tom

[Elusive R]

I'd have to check, but I think my hydraulics are pretty much the same setup minus the Lakewood bell, fork, and pivot. I'm also running a Wilwood 7:1 pedal and I have to use a very large amount of travel to get the clutch to disengage. Is there any way you can get more travel? I'd check everything again - are you sure you have the right fork? IIRC, I don't remember having too much more slave travel than you do. Clutch works great, I just need a bigger master to shorten the pedal throw.

Ryan

[Madspeed]

Do you have the wrong T/O bearing?
There is a short and a long

[Hurst - Jeff]

Here are a few things to think about:

Before you read on it is assumed that your clutch fork angle is set correctly. If it is not, then you ned to get that straightened out first. Read here about how to set your clutch fork angle:
http://www.classicchevy5speed.com/files/Clutch_Fork_TO_Bearing_instr.pdf (http://www.classicchevy5speed.com/files/Clutch_Fork_TO_Bearing_instr.pdf)

1) You should be using a clutch fork with a 2:1 ratio (6" from pivot ball point to end of fork where linkage attaches). If you have a longer fork this will be causing part of your lack of travel problem.

2) Ideally the master and slave should be matched - in other words a 7/8" slave should be combined with a 7/8" master or maybe a 13/16" master. The smaller master is contributing to the lack of travel issue - you ar enot moving as much fluid as you could be. You can probably get away with the 3/4" master if you have the 2:1 fork and a 10.5" clutch (see clucth comments below)

3) If you are using a 12" clutch disc this will also contribute to the travel problem. The larger diameter clutch disc you have the farther the pedal needs to travel. An 11" would be better off and a 10 1/2" would be better yet.

Here is a link that has a great deal of info about all this stuff:
http://www.novak-adapt.com/knowledge/clutches_etc.htm (http://www.novak-adapt.com/knowledge/clutches_etc.htm).

I hope this helps somewhat.

[67greengt]

First of all thanks for all the quick replies...

Did some more fiddling today and came up with the following.

With my current setup of a CNC 3/4" master and 7/8"s slave I realized, after stopping completely and looking at the logic side of things, that I'm not going to get the 1.5" of travel out of the slave that cnc says I can get. I guess this is because I'm running a smaller master thus, resulting in less displacement on the slave end, causing a lack of travel in the slave. I checked the master to make sure I was getting all the travel out of the master and I am. I'm getting 1.5" of travel out of the master. After looking at the logic side of things once again I realized that because of the difference in volumes because my master is smaller I won't match this 1.5" of travel at the slave, instead I'll get about 1 1/8" at very most, which is what I'm getting. My plans are to try a 3/4" slave next as the cnc master I'm running fits so well in the car.. Failing this I guess I'll try going up to a 7/8" slave and see where that puts me. I'm really hoping that the slave will do it.

I just can't believe how difficult I've made it! Instead of looking at the physics end of it I was stubborn on copying the JMC kit and for w/e reason my setup doesn't want to work with what they use for all their kits..

In other news... I just picked up my custom one-off shifter handle for my TKO600 made by Speedtech Performance. Todd did an excellent job, the shifter is now tailored to me. My right shoulder never even comes close to coming off the seat when shifting thru all the gears. I'm really looking forward to getting the clutch sorted out and putting some miles on it...

Oh yah, I'm gonna order my wheels on thursday

Boyd Junkyard Dogs 18x9's in the back and probably 18x8's in the front... can't wait!!

Thanks again for all the help
Tom

[Elusive R]

Tom,

Best of luck getting things straightened out. When I talked to CNC about it, they suggested a 3/4 master with the 7/8 slave for a lighter pedal feel. If I can ever find a mini-master with a 7/8" bore, I'll be all over that, but the biggest 'mini' that Wilwood made when I got mine was 3/4". Oh well - it's just money, right?

Ryan

[Hurst - Jeff]

Not to wreck your plans of trying to use a 3/4" slave but if you do your pedal will become very hard to push. I just went through th exact same excersize - had a 3/4" master and 7/8" slave and did not have enough travel. I changed the slave to a smaller 3/4" bore and I did get barley enough travel but the pedal was way too hard to push.
I thnik the right call is go with a larger master an dstay with the 7/8" slave.

[Elusive R]

Jeff,

Thank you for the heads up on the smaller slave. I will keep that in mind whenever I get myself a new clutch master.

Ryan

[67greengt]

I'm going to try to bleed the 3/4" slave tonight and see what happens, if it's way too hard I guess I'll have to order a 7/8" slave, I just hope it fits the same way the 3/4" one did...

Thanks again
Tom