Hydraulic clutch fundamentals

-
V

volaredon

Well-Known Member
Joined
Feb 28, 2010
Messages
3,643
Reaction score
2,060
Location
IL
While my particular applications arent an a body
I have 2 projects for which I am wanting to convert to a hydraulic clutch. One a D150 and one an F body, both mopars. Both factory automatic vehicles. I have factory clutch pedals here for both.
While I know that the Dodge trucks just a year or 2 newer than mine came factory with a hydraulic clutch, back when I first talked about (possibly) adapting a factory truck hydraulic setup to the F body wouldn't work because those systems "suck"
so I'd be better off to start from scratch and go with a tilton/McLeod/wilwood setup. While I never got any reasons why the stock systems "sucked" I have a used setup here from a 92/93ish D250 with a diesel here. It really don't look all that different from what I have had on my (factory equipped) Dakotas and wrangler-- which I know for a fact that those two take the exact same hydraulic setup as each other. I didn't seem to have any problem with either of those so I don't get why people claim that system "sucks". It's a matched system where the master and slave bore diameters are matched and calibrated to each other. Being plastic they do seem a lil chincey.. and good thing they're available assembled and pre bled as there is no bleeder on either cylinder. And both components can be bought separately so there would have to be a way to bleed them. That, I can see being sucky to accomplish.

I've looked around online til I'm about blue in the face.... I can't find a bit of info to tie together any sort of relationship in bore/stroke size desired between master and slave cylinder sizes. I know the circle track guys use wilwood stuff all the time as do people with older hot rods such as the "T bucket era".
If someone were to want to build an aftermarket system how do you determine which master and which slave to pair up? Would internal slave be a better option? Do they even make such an animal for tranny's such as an 833OD? Do they work ok with borg and beck style pressure plates or is a diaphragm necessary? Going back to the Dakotas and wranglers I have owned they all were diaphragm clutch. I just got a new clutch kit for my D150 and they (rock auto) sent a 3 finger style. Even though the pix associated with this PN show a diaphragm pressure plate.
The only thing I CAN seem to find is info about pedal ratio.
And we're not talking Shivvys or fox body mustang, where there are "matched retrofits" galore ... Being Mopar we are typically "on our own" to figure out. Hard to do without info to help determine parameters that "go together". And buying multiples, installing each and "trying them" then buying another to try and dial in a setup is too cost prohibive// for me anyways
 
Last edited:
Has anyone here ever done such an install that could provide some insight? Or know of a website or 3, that tell of such info that would be needed to help decide which components to get?
 
Vendors such as Silver Sport or American Drivetrain could sell you a master/slave/line/mount kit. If you call them up they could probably sell you matched components.
 
Ok.. what guidelines do THEY follow to match a given master with a given slave whether internal (hyd throw out bearing) or external style slave?
 
not done it
but i did research it
with an eye on reliable OEM parts, easy spares and not needing to pull the box and bell should the slave cylinder leak.

but if i was going to i'd use 80s chevy s10 master 82-92
Clutch Master Cylinder For 82-93 Chevy GMC S10 Sonoma Blazer S15 Jimmy DV22M2 | eBay cut off the eye, thread and use a rose joint at appropriate length. bolt and spacer at peddle.
it has more or less the right angle of dangle to its mounting to work without the usual machined piece necessary for a 90 degree mounting wilwood style on a mopar

on the clutch end 3 series or 5 series BMW parallel mount pusher on the standard fork

id use the standard fork
a mopar truck hardend steel part on the clutch rod in the fork eye. don't need the fat washer and rubber bit if the peddle is not directly connected to the vibrating drivetrain

i'd build an angle iron bracket on the clutch z bar ballstud mount which is now obsolete
and id use this
https://www.autodoc.co.uk/febi-bils...DnBCJZaBaNmTxNDiswL-J1SwX4Pnj8LxoCH5wQAvD_BwE
to push my clutch fork.

A shoddy way to feed it with fluid, would be to drill and tap for pipe fitting a hole in the big section of the brake master cylinder side wall, well above the level of no juice but just below the level the fluid falls to at full on brakes.
that way if you clutch fails and pees out brake fluid your brakes will still work

run brake pipe or rubber pipe down to clutch master and fill/ bleed from the brake master.

proper way would be its own bottle or half shoddy way, a brake master with a top bottle = more capacity

but if you buy a bottle may as well get the chevy one

it may not work, i never got that far
variation in bore will dictate peddle travel to some extent. but keeping it all passenger car parts reduces the risk.. bus and truck parts would cause issues


cheap way in to a hydrualic clutch which avoids all the shimming and messing about with those expensive concentric slave cylinders. BMW and chevy dudes have tested this gear out in the millions worldwide for the last 20-30 years

Dave
 
Last edited:
Being I'm currently working on a truck, though I was thinking of going aftermarket because all I have heard about the stock later 80s hyd system hasn't been good.... does anyone here have any real world exp with the stock type hydraulics?
Another thing is, most I've seen with a hydraulic clutch use a diaphragm pressure plate. All I could find for my application even in an 87 that shows hydraulic actuation as std equipment is a 3 finger conventional pressure plate. Will this cause any issues? Thats one thing I hate about computer driven application guides. Back in the day I could flip a real paper catalog to the "buyers guide" and see specs of the various PNs of whatever part I was wanting, compare numbers and decide if an alternate would work much easier.
My app is a /6 D150 with an 833 OD. (would like to run something like a T5 but I have what I have and thats what Im gonna run) Far from a race truck, though I have made some upgrades to my particular engine. gonna use as a 3 season daily driver, camping rig, occasionally pull a small utility trailer short distances (~30 miles at a time 1-2x a week) with a few mowers loaded on it....
 
I could do with what I have, I believe. Might need bushings in the Z bar if I stay with mechanical linkage.

I did buy a factory-style replacement master/slave combo via Ebay. so if I go hydraulic, Im gonna try that first, and see how that works out. I do have a couple of these in used form as well, courtesy of my kid.

The guy I got all this 4 speed stuff from, got all of it as he could find it, in several junkyard trips over the years. all is marked what year it came off of, all is '81-87. seems very complete from what I remember. it's been a couple of months, since I looked at it all. I know for sure that the bellhousing I have does have the bracket on it to mount the factory slave.

He redid an 83 D150 and I think just gathered parts as gettin was good, "just in case" he needed them for his, which is a factory 4 speed truck.

I've asked this question about the hydraulic clutch idea, on a couple of forums. On one of those other forums, someone posted a pic of a factory /6 bell with the bracket for the slave on it. My bell has that bracket. But the fork that he showed, looked kinda weird. It wasn't straight, had a weird rearward curve to it. so I might need that.
Also, the clutch pedal I have (made for mechanical style linkage) looks different from what I am now seeing, has a metal strap welded to it at an angle to offset the pin to connect to the master pushrod further over towards the left. I'm sure I can fab that up, and modify what I have easy enough to match that configuration if need be.
truthfully, I need to get back into that tote and see exactly what all is present again, now that I'm getting closer.
I would like to eventually find a column for a stick equipped truck, or at least the "shift bowl" to swap out the one on my column now where the A/T shifter goes....
The one thing I will definitely need is the angle bracket the master clips into, behind the firewall. My kid pulled the one from his truck, I think between us, we can make that ourself.
The other thing I know I need, is whatever retainer clips and/or any bushings where the master would connect at the pedal.

this brings up another related question. What is difference in driveshaft length as compared to same truck with a 727? (since that's what I have in truck now)
 
You must log in or register to reply here.
-

Back
Top