SM465 Hydro clutch conversion problems

[Matman2010]

I have an 84 chevy crew cab that I converted to 4x4 and also converted to a manual transmission. I have all the hydro pedal assembly and got the master and slave cylinder out of an 85 chevy truck. I am having trouble not getting enough travel out of the slave cylinder to disengage the clutch. The motor is an 84 J-Code 6.2 and I am running a 76 SM465 with a Np205 and I made my own bracket to mount the slave cylinder. (Cant post a picture of it, but it is lined up right with the fork)

Everything for the clutch is for a mechanical linkage, It seems from what I have found there isn't really a difference in the forks between a hydro and mechanical. I am currently getting about 1 inch of travel out of my slave cylinder, I have found that I need at least 1.5 inches to get it to disengage. I am using all the factory master and slave cylinders and from what I have heard the mechanical clutches will disengage with 1 to 1 1/8 inch of travel on the fork. So where could my trouble be at? I am pretty sure that I got all of the air out of the system, but it seems that I am getting a 1 to 1 ratio between the slave and master. I have pulled the clutch back out and it seems like everything is working just like it is suppose to but I am not sure why I need 1.5 inches of travel vs the 1 inch people keep saying it should be.

Thanks, Matt

 

[sweetk30]

there is a diffrence in the forks but only if running true hydro clutch bell housing.

and thay can be a b!tch to blead out.

read my story and troubles here for good info and bleading tips. http://coloradok5.com/forums/showthread.php?t=200196&highlight=hydro

 

[Matman2010]

Thanks for the link. I am pretty sure that I have all of the air out of the system, the pedal is not spongy at all like there would be air in the system and i seem to get the same movement out of the slave as I do on the pedal, I also get the same amount of movement every time. Do you have any known pre-load on the clutch at all with the hydro setup? How far does your slave cylinder move? I was bench testing my clutch pack the other day to see how much it would have to move to get it to release and it had to move 3/4 in on the fingers of the clutch to disengage, and the fork is a 2:1 ratio from the hydro to the throwout so that means I need at least 1.5 in of travel on the hydro to be able to release. But several guys with mechanical systems have told me they only get 1 inch of travel at the fork to disengage their clutch, and that is all I am getting out of my slave and it is not working.

 

[sweetk30]

yes there is a bit of preload on the slave but not much . and as to the rest of your questions sorry cant help as i sold the 465/205 with hydro parts and went th400/205 few years ago. got tired of shifting when plowing and city driving.

 

[Matman2010]

Is there anyone else on here running a hydro clutch setup that they could measure the movement for me?

 

[sweetk30]

lots here have it. give them time to post up someone will help ya .

 

[big dan]

Im running a sm465 with full hydro clutch fin an 86 k10 and had the same problem as you when I installed it. I bled the system till I was certain there was no air. Though it may not be the correct way but I pulled the slave cylinder and welded a piece of small steel tubing on the end of the rod to extend it about 3/8s of an inch and it has worked perfectly since then.

I dont remember what the travel on my slave was but it seems like it was quite a bit. The rod was extended a ways before it got to the fork. I also resurfaced my flywheel and have no idea if it had ever been resurfaced before, Im sure that my problem was just that the flywheel was machined down far enough to where the slave couldnt reach to engage properly.