peter.scannell

I replaced my Brake master cyl, clutch master cyl, dread blue hose and my slave cylinder and I think I have an engagement problem. It feels like the clutch is not fully engaged. The slave cylinder I used was for a 83-86, my car is an 1980. Are the rod lengths different and can I change the rod without disconnecting the slave from the hydraulic line?

Thanks Peter

blown 87

I am interested in this also, we had to shim the slave out when going to a dual disk set up which is not a good solution.

peter.scannell

How far out did you go to engage properly?

blown 87

Far enough to make it engage and still release, trial and error.
In other words, I never measured it.

jcorenman

Peter,

There are at least two different rod lengths for clutch-slaves. The rod for a S4 (single disc) clutch is 154mm (overall length), and the dual-disc rod is shorter-- I will pull it this afternoon and measure it.

The hard-line on the clutch slave is trapped by the starter, if you remove the clip that attaches it to the bracket on the driver's side of the oil pan then you may be able to get the slave out without disconnecting anything. (You will probably need to grab the rod with long-nose pliers and shove it back into the cylinder in order to get it out of the housing).

The hot setup is to get a new clutch hose from Greg Brown and route it around the front of the starter. That avoids the trapped-hardline problem and makes removing both starter and clutch-slave much simpler. I'll post a picture this afternoon.

Cheers, Jim

Giovanni

I am interested in buying the shortened style rod. Please PM me.

blown 87

The short rod from a 80 is 5.455 inches.

peter.scannell

Thanks guys, I re-ran all my lines, hard and soft, never had the pesky bracket. The final I had to order from Germany and it was wrong (naturally) so I bent it by hand and shortened it. I have a dual disk clutch and the rod feels like it wants to be shorter. So before I start grinding I thought I'd ask the experts!

The hot leads for the starter are nicely exposed down there! watch out!

Other project today was reinstalling my "perfect" pod. I replaced the circuit board, broke two of the connectors, fixed them (gorilla glue) and rebroke two on upon final install. Everything works, mostly, so WTF! Can't wait to drive this sucker, it's been years.

Wow, That's alot almost 5/8"

dprantl

Ok, so to double-check:

- The long rod is 154mm
- The short rod is 138.56mm

Is this correct? Are the internals of both the short and long cylinders the same so the rod is the only difference?

Dan
'91 928GT S/C 475hp/460lb.ft

dprantl

Jim, any update on this? What I would really like to know is the measurement of the rods of an old and new slave cylinder from the end to the cylinder body when fully retracted.

Dan
'91 928GT S/C 475hp/460lb.ft

blown 87

Why cant you just pull the rod out and measure it?

dprantl

I can, but that won't be very useful. I am not sure if the cylinder bodies are the same and also don't know if both cylinders allow the rod to be pushed in the same distance. Maybe I'll just get an older cylinder and stick it in there.

Dan
'91 928GT S/C 475hp/460lb.ft

blown 87

Pretty sure the bodies push the rod out the same.
It worked on at least one, just changing the rod.

jcorenman

Dan, Sorry for the delay! I pulled the rod from our 88s4, which we retrofitted to a DD clutch with an old-style slave. The rod measures 138.70 mm, same number as Greg. There is no other difference that I can see between the cylinders themselves, but I did not measure that.

Cheers, Jim

User 4221

I went through this with my '81. What I found was the new master cylinder diameter was smaller (not by much) than the old one and it could not displace enough fluid to actuate the slave cylinder.

I had to rebuild the original master and re-install. It worked fine after that.