Installing Hydraulic Master Cylinder

[jaxjeeper]

I am doing a repower of my 1984 Jeep CJ7 . Part of the process will be converting from the old mechanical clutch to a hydraulic clutch.

How do I mount the master cylinder? Is there a thread or blog that shows pictures? I am guessing the pushrod goes through the firewall and connects to the clutch pedal. When the clutch is pressed, the pushrod causes the fluid to compress which signals the slave to disengage the clutch plate. I'm just not sure how the pushrod is connected to the clutch pedal.

Do you completely remove all the old mechanical clutch linkages?

 

[ThisGuyUKnow]

Since you have an 84, you should have a stamped out section on the fire wall where a hydraulic matter would go. What you should do, IMHO, it's get a clutch assembly from a 87-90 yj as well as a master from those years. The master is the correct width for the section on the fire wall.

It will all bolt in work properly and look Right.

 

[Purple77CJ7]

After I mounted my clutch master cylinder and had the push rod through the fire wall, I just lined it up beside the clutch pedal arm level and drilled a hole to pin it to the arm. And yes you get ride of all the mechanical linkage. One thing you may have to pull the tranny and bell housing to reposition the clutch fork. It depends on what your tranny is, and how a slave cylinder will mount. You can check out Advance Adapters and Novak Conversions, they have some articles on how to.

 

[jaxjeeper]

Thanks for the reply. I purchased the powertrain from Novak so the Slave is already set up. Did you connect the pushrod directly to the clutch pedal or was there another part involved? Is it possible to post a picture of the assembly? That would help enormously. Thanks again.

 

[tarry99]

Thanks for the reply. I purchased the powertrain from Novak so the Slave is already set up. Did you connect the pushrod directly to the clutch pedal or was there another part involved? Is it possible to post a picture of the assembly? That would help enormously. Thanks again.

If yours has a knock out on the firewall that should get you close. That year came with a GM 4 cylinder and that is what used the hydraulic clutch. The OEM part number for the Clutch Master for a Dorman is #106439 and that is a 13/16" bore.

So without getting to technical , what size Novak slave do you have? The ratio needed is about 6-7:1 which has to be maintained coming off of the clutch pedal to your master slave push rod contact point. If all the original components are still in there a hole in the clutch pedal may already be there...............It will be important to get enough travel in the push rod at the clutch pedal to push enough volume (brake fluid) to the slave to move the pushrod that pushes the clutch fork. If both bores (clutch master & slave) were equal size then that would be a 1:1 ratio so for every inch of movement at the clutch pedal you will get 1 inch of movement at the slave.
If you noticed above the stock bore master was 13/16" . I would guess the Novak slave you have is a 3/4" the most common they sell......if you were to use that combo because of the larger bore at one end you will get a little more travel at the slave..........that is a designed in function in that model.

So lets say you have one inch of travel at the slave......keep in mind the ratio changes at the clutch fork ball inside the Bell Housing to 2:1.........meaning now for every inch of travel you have at the slave you only have 1/2" inch at the throw-out bearing.................most clutches need about .400 to .600 of an inch of travel to release.......add in some freeplay and that number can easily get to needing .750 inch of travel............which at the slave would now be.........about 1.5" of travel................easy to get there as long as you understand and apply the ratio's and amounts needed along the path.

 

[Purple77CJ7]

Thanks for the reply. I purchased the powertrain from Novak so the Slave is already set up. Did you connect the pushrod directly to the clutch pedal or was there another part involved? Is it possible to post a picture of the assembly? That would help enormously. Thanks again.

I will try and get a few pics tonight after work.

 

[jaxjeeper]

I believe we have figured it out. We successfully removed the clutch pedal, drilled a hole, and connected the pushrod. That little snap ring was a pain in the arse.

Thanks for all the replies.

 

[Purple77CJ7]

Glad you figured it out. I was not having any luck with a old digital camera and a new computer, to get some pictures for you.