C6 to ZF5 clutch hydraulics question

1983idi · Jul 25, 2017

So i am trying to get everything together for my swap before i start. I have the clutch pedal already installed. I have the transmission, clutch, flywheel and slave/master cylinders from an 89 idi. The master cylinder doesn't look like it will fit so do i just need to make it fit or is there a different one i need to get. Also if i have to use a different master can i use the same slave?

IDIBRONCO · Jul 25, 2017

If your truck was originally an automatic, then it didn't come with a master cylinder and you'll have to make it fit.

bike-maker · Jul 25, 2017

There should be a dummy plate bolted in the firewall.

I used a 89 donor for mine as well, so I'm guessing the issue your going to find is that the bolt pattern is different: 83-86 had the studs on the master horizontal with its bore. On the 87-91 the studs are diagonal. I just drilled new holes and used one of the big firewall reinforcement plates.

riotwarrior · Jul 26, 2017

May have to get a mc from your era...up to 86 as iirc they changed mounting hole options.

Also look into the firewall fix plate for solvimg issues before they happen @freebird01 pm him its worth the investmemt and time to install

Fixes firewall flex. There are a couple articles in the tech section up top.

JM7.3CW Eh!

junk · Jul 26, 2017

To me it would be easier to get a new MC. They're like 20 bucks for a good one. Not worth the hassle drilling the holes.

hesutton · Jul 26, 2017

junk said:
To me it would be easier to get a new MC. They're like 20 bucks for a good one. Not worth the hassle drilling the holes.

+1. They are cheap. I got new aluminum master and slave from RockAuto a few years ago for my '86 cheaper than I could get them from a local parts store. Shoot they were about the price of used units I've pulled at junk yards. Up high under the dash/firewall is a pain to drill holes in. LOL

Heath

1983idi · Jul 26, 2017

IDIBRONCO said:
If your truck was originally an automatic, then it didn't come with a master cylinder and you'll have to make it fit.

I know i will have to drill holes with either one. I just didn't know if i would need an era correct master cylinder or of if an era correct master cylinder would even work with the slave the zf5 uses. It sounds like i would be best off getting the plate that helps with firewall flex for an 89 and using the master i have and just drill the holes different

bike-maker · Jul 26, 2017

My 84 had the holes, maybe 83 is different?

My reasoning for using the existing master cylinder was so I didn't have to deal with bleeding it.
And I'm a cheap *******.

Over course, when I was wrestling the IDI in place, the valve cover pinched off the hydraulic line between the master and slave, so I got to partake in the enjoyment of bleeding it anyway......

madpogue · Jul 26, 2017

My '85 has one of the firewall reinforcements; I forget which. I adapted an OBS-style master-line-slave to it, also to avoid bleeding. Had to clip off a corner of the mounting flange of the master, to clear a flange on the reinforcement. Also had to egg out one hole on the mounting flange of the master, and one hole in the firewall, and used my own stainless bolts/washers/nuts. Works like a charm. Yeah, that's the direction I'd go, not only to avoid the bleeding, but because you know the master and slave are compatible.

hesutton · Jul 27, 2017

My '86 had a small plate over the firewall where the master mounts. All I had to do was pop off the plate and bolt the master in.

Not sure about early rigs.

Heath

C6 to ZF5 clutch hydraulics question

1983idi

Registered User

IDIBRONCO

IDIBRONCO

bike-maker

Full Access Member

riotwarrior

Supporting Member

junk

Full Access Member

hesutton

The Anti-Anderson

1983idi

Registered User

bike-maker

Full Access Member

madpogue

Full Access Member

hesutton

The Anti-Anderson

Similar threads

Latest posts

Forum statistics

Members online

Share this page