Slave Cylinder Sizes

[Arne]

Add ^^ - The Parts CD also shows the same 6/72 change point for the clutch fork, so apparently the adjustable slave cylinder was used for '72 Type B trannies as well as for the Type A's.

Still don't know which slave bore is correct...

[geezer]

Arne, I have the Dec/79 microfiche, which is the last revision for US/CAN. There are a total of 6 clutch master cylinders listed for the S30 as supercessions. All manufactured by Nabco. The first two ( 30610-E4100 ) & ( 30610-E4101 ) don't have "from or up to" dates associated with them but the third ( 30610-E4200 ) has an "up to" date of 08/74. None state a bore size.

The only slave cylinder shown relevent to your car is made by Tokico, has a 11/16" bore with an "up to" date of 6/72. The part number is 30620-28513. From 7/72 - 6/75 a 3/4" bore is used, also made by Tokico ( 30620-S0100 ). "From" 07/75 part number 30620-U7000 with a 3/4" bore manufactured by Tokico is listed.

From the S130 microfiche there are 3 other slaves listed, all from Nabco. None define a bore size, but the first is 30620-U7000 used "up to" 11/80. We already know from it's use in the S30 that it has a 3/4" bore.

"From" 12/80 30620-U7001 is used and the last one listed has a "from" date of 01/82. It is part number 30620-P9500 (turbo). No bore size stated.

John, hope this helps fill in some of the blanks. If you need any other part numbers/dates of the pushrods or anything else, give me a holler.

Edited May 3, 2009 by geezer
more info added

[gnosez]

I have the 5/8 MC and the 11/16 slave in my 240 as well but I have a 280B tranny.

The FSM is fine as long as you keep everything stock.

[Arne]

I'm still wondering about the disagreement between the original FSM and the '79 parts fiche/CD and other current parts lists. Were there any TSBs regarding clutch slave cylinders for 240Zs? Was the 5/8" bore the original size, and then there was a running change later to 11/16"?

[gnosez]

For such a simple question there seems to be little agreement as to what came with what and for that matter why.

[geezer]

I'm still wondering about the disagreement between the original FSM and the '79 parts fiche/CD and other current parts lists. Were there any TSBs regarding clutch slave cylinders for 240Zs? Was the 5/8" bore the original size, and then there was a running change later to 11/16"?

I looked for some explanation in the TSBs and didn't find any reference to the clutch slave cylinders.

TS70-44 dated Oct 12/70, subject: 240-Z CLUTCH IMPROVEMENT, explains the 3 modifications made. These were changes made early on.

There's nothing else in the TSBs that I could find other than TS75-021 early in '75 covering S30 Clutch Control System Disengagement.

There may be something mentioned in the S30 Supplement Chassis Manual, issued Jan 5/72. It applies to 240-Z models through 1971, but if IIRC it is mainly focused on the dash and wiring. That's all I could come up with.

[Arne]

Is it just me? Does anyone else have a Factory Service Manual that claims the slave should be 5/8"? If so, what year was the manual published?

[geezer]

Looking in the FSM for 1970, (P/N 99999-20016 gold covers) the same 5/8" slave is shown. The change to 11/16", if not noted in the S30 Supplement Chassis Manual, with the relevent revisions through 1971, may have come about without the need to give notice to the Service Department. Maybe, because of the versatility gained with the adjustable pushrod and the relatively small increase in the bore diameter it went unannounced outside of the factory and only shows up in the Parts Fiche & Catalogs. I checked and there also is no mention of a slave bore diameter change in the 1972 240Z Intro TSB either, but that is not very comprehensive. I don't have any FSMs for other years.

We need someone to check their S30 Supplement Chassis Manual and other year FSMs for the bore diameters shown for the clutch slave cylinder.

Edited May 7, 2009 by geezer

[Arne]

I would be interested to know if anyone with a '70-71 240Z still might have their original slave cylinder to check the bore size. After all these years its not likely that it might still be on the car and in functioning order, but perhaps someone may have kept one when the original was replaced? I'm still wondering about a running production change.

On the other hand, even if there was a change from 5/8" to 11/16" at some point, you would think that the parts fiche/CD would at the very least list a 5/8" rebuild kit for the earliest cylinders, assuming that there were any such beasts. So maybe they were always 11/16" bore, and the '71 FSM (as well as the third party SM I have) was simply wrong. Although the 5/8" bore is mentioned in more than one place, I think.

[TVollnogle]

I dug my old master and slave cylinders out of storage today and checked sizes. The master that was on my '70 4/70 is 5/8" and the slave is 3/4". The slave does have the adjustable rod.

I don't know that either one is original, and from the previous info, probably have a later model slave.