Building a better ZF5 slave cylinder fitting

[Kinder]

What he said^!

[Justin]

x3. Always impressed by your handiwork.

[Digger]

She works!

In 20 years and 4 trucks with concentric slave cylinders, this weekend was the first time I could not get one to bleed correctly. I now know Eck's frustration after bleeding all day Saturday, bench bleeding the master twice, and rechecking every connection including the quick connect.

I finally gave up and pulled the transmission and reconnected the slave by itself. Using a giant threaded rod to hold it together, I reconnected it and it still won't bleed, but I could hear the air being sucked into the slave every time someone let off the clutch pedal. I gave up and replaced the slave. The new one bled the air in one pump.

Taking the old unit apart, I could see that the seal was crooked and not sealing properly. Looking at the seal design, I think I understand why this design is so problematic for so many people. It's not necessarily good or bad parts, but a susceptibility of the seal to suck air or tip during the bleeding process.


All that aside, the quick connect works great.






The instructions for the new slave cylinder give some insight into the different fittings I found in the box of goodies from Eck. It does appear there are two distinct sizes of quick connect. The more common one I've seen (black) has a mating diameter of ~.61" and the smaller one is gold in color and measures ~.56".

[pgilbeau]

Something I noticed when sourcing parts for my ZF-5 was that there is a split around 1991. On the O'Reilly site all the part numbers for the slave, master, and hose are different from 1991 down. The black connector goes with the "early" 1991 down stuff and the gold goes with the "later" 1992 up stuff. The part numbers are Dorman 628-203 for the "early" and Dorman 628-201 for the "late." It does list the connectors as different sizes. I noticed this because my transmission has an '89 build date and I had a '95 master, neither hose would work. That being said I think you have to match the slave, master, and hose with the correct "early" or "late" version.

[Kinder]

So where do I sign up on the order sheet to get this kit?

[phyler]

So where do I sign up on the order sheet to get this kit?

X2. Can't wait for the Digger store to open. All I hear in my head when reading a Digger thread is "shut up and take my money."

Sent from my Venue 8 7840 using Tapatalk

[Eck]

See, I wasn't ! I think the moral of the story is to bleed the slave before bolting up the transmission. If it doesn't bleed after 20 minutes, return the slave cylinder and get a different one!

Glad your parts are working... remember I have rights to the first production unit off the line!

[Justin]

x3. Shut up and take my money.

[Gunnibronco]

Something I noticed when sourcing parts for my ZF-5 was that there is a split around 1991. On the O'Reilly site all the part numbers for the slave, master, and hose are different from 1991 down. The black connector goes with the "early" 1991 down stuff and the gold goes with the "later" 1992 up stuff. The part numbers are Dorman 628-203 for the "early" and Dorman 628-201 for the "late." It does list the connectors as different sizes. I noticed this because my transmission has an '89 build date and I had a '95 master, neither hose would work. That being said I think you have to match the slave, master, and hose with the correct "early" or "late" version.

From what I'm reading, I assume the part are for the early ZF slave cylinder.(?) The master in the pics is the early type.

[pgilbeau]

From what I'm reading, I assume the part are for the early ZF slave cylinder.(?) The master in the pics is the early type.

I was just pointing out there is two versions and the connectors are different, I didn't realize it initially when gathering parts and thought others may not realize it either.

[Gunnibronco]

I purchased the 'later' stuff at first. When I inspected the trans I had, I realized my slave cylinder was different. I did research, and realized that there were 2 master/slaves as well. I bought a set of the 'early' stuff and have it installed now.

Since the fitting at the slave changed size (something I didn't realize) with the change from 'early' to 'late', I'm just assuming his won't fit the later slave.

I bought the BC Broncos hose, I think it will fit both the 'early' and 'late' set ups. But I like this because you can remove the hose without removing the transmission (making trans removal easier). The roll pin can only be removed from the BC set up with the trans out, and I believe the slave out of the trans.

[Eck]

I purchased the 'later' stuff at first. When I inspected the trans I had, I realized my slave cylinder was different. I did research, and realized that there were 2 master/slaves as well. I bought a set of the 'early' stuff and have it installed now.

Since the fitting at the slave changed size (something I didn't realize) with the change from 'early' to 'late', I'm just assuming his won't fit the later slave.

I bought the BC Broncos hose, I think it will fit both the 'early' and 'late' set ups. But I like this because you can remove the hose without removing the transmission (making trans removal easier). The roll pin can only be removed from the BC set up with the trans out, and I believe the slave out of the trans.

Digger's solution also closes the system when you remove the line not allowing air into the slave. Will make it easy to bench bleed your whole system, then install the slave and transmission without the line in...

[pgilbeau]

Digger's solution also closes the system when you remove the line not allowing air into the slave. Will make it easy to bench bleed your whole system, then install the slave and transmission without the line in...

Yeah, would definitely be interested in acquiring this set up, especially since my clutch isn't bled yet. Take my money and save me some time!

[Digger]

Something I noticed when sourcing parts for my ZF-5 was that there is a split around 1991. On the O'Reilly site all the part numbers for the slave, master, and hose are different from 1991 down. The black connector goes with the "early" 1991 down stuff and the gold goes with the "later" 1992 up stuff. The part numbers are Dorman 628-203 for the "early" and Dorman 628-201 for the "late." It does list the connectors as different sizes. I noticed this because my transmission has an '89 build date and I had a '95 master, neither hose would work. That being said I think you have to match the slave, master, and hose with the correct "early" or "late" version.

Using OreilyAuto, the split appears to be mainly between '92 and '93, but there is some variation depending on application.

Yes, master and slave need to match, as the older units used a 7/8" bore master and the later units used a 18mm bore MC. I would only guess the slave has similar size differences.

I not sure about what the quick connect break is, but the pictures on Oreily show the gold connector on the later models and the black on the early ones.

Mine is the earlier, large size quick connect, which seems to be more popular, but I don't see why the later one couldn't be replicated.

[pgilbeau]

Yep, I will have to verify tomorrow, pretty certain I have the early slave at this point. Any chance you are going to make a run of these for club members?

[Digger]

So where do I sign up on the order sheet to get this kit?

There is definitely enough interest to pursue this one. I need to find a machine shop to farm the work out to. I'm too slow on a manual lathe and there is a lot of important dimensions and surface finishes. Probably need to make 20 units to spread out the setup costs of the 3 machined parts. So needless to say, I have some work to do.

[pgilbeau]

Using OreilyAuto, the split appears to be mainly between '92 and '93, but there is some variation depending on application.

That makes sense, think I looked it up using an F-250 w/5.8

[Eck]

I'd bet you would get enough interest both locally and nationally to unload 20 units pretty easy.

It's been a little while but I know I bought the MC that has the 90 degree angle instead of the straight out connection. I can't remember which donor vehicle made the distinction and I'm curious if that fitting uses the same diameter as the late or early style slave/MC combo.


Sent from my iPhone using Tapatalk

[pgilbeau]

It's been a little while but I know I bought the MC that has the 90 degree angle instead of the straight out connection. I can't remember which donor vehicle made the distinction and I'm curious if that fitting uses the same diameter as the late or early style slave/MC combo.

I originally had the early slave and a late master from a '95 F-250 which is one with the hose attaching at the bottom. That was the problem for me, the Dorman hoses would only fit the master or the slave with an early/late combo because the couplings are different on both ends. As best I can tell you need to either have all early or all late of the slave, master, and hose.

[Eck]

It's been a little while but I know I bought the MC that has the 90 degree angle instead of the straight out connection. I can't remember which donor vehicle made the distinction and I'm curious if that fitting uses the same diameter as the late or early style slave/MC combo.

I originally had the early slave and a late master from a '95 F-250 which is one with the hose attaching at the bottom. That was the problem for me, the Dorman hoses would only fit the master or the slave with an early/late combo because the couplings are different on both ends. As best I can tell you need to either have all early or all late of the slave, master, and hose.

Ahh, gotcha. I never used the Dorman lines, just the BC braided line. I'm guessing the quick connect is the end that doesn't fit universally?


Sent from my iPhone using Tapatalk

[Digger]

It's been a little while but I know I bought the MC that has the 90 degree angle instead of the straight out connection. I can't remember which donor vehicle made the distinction and I'm curious if that fitting uses the same diameter as the late or early style slave/MC combo.

I originally had the early slave and a late master from a '95 F-250 which is one with the hose attaching at the bottom. That was the problem for me, the Dorman hoses would only fit the master or the slave with an early/late combo because the couplings are different on both ends. As best I can tell you need to either have all early or all late of the slave, master, and hose.

Ahh, gotcha. I never used the Dorman lines, just the BC braided line. I'm guessing the quick connect is the end that doesn't fit universally?


Sent from my iPhone using Tapatalk

The fittings where the roll pin is retained are all the same and seem to be standard across different manufactures. That being the case, you have one or two large female quick connects in that pile of parts you loaned me. It would be easy to change the fittings on the slave. My concern would be your fender clearance with you MC's down-facing port.