1991 slave cylinder large vs. small bore

[mike100]

my original slave was weeping a little and ran the res dry. It still doesn't work as well as it should even after a bleed.

I bought a new one locally, but it is the larger 1-1/8" bore size and mine is the smaller one. I heard that there were two sizes on the 91's and that the later cars with ZF6's all use the larger one.

Can I use this with the orig master hydraulic?

[mike100]

rod length appears to be identical

http://i29.photobucket.com/albums/c265/mschrameck/Cars/DSC03698.jpg

[tomtom72]

my original slave was weeping a little and ran the res dry. It still doesn't work as well as it should even after a bleed.

I bought a new one locally, but it is the larger 1-1/8" bore size and mine is the smaller one. I heard that there were two sizes on the 91's and that the later cars with ZF6's all use the larger one.

Can I use this with the orig master hydraulic?

Okay I have a 90, but the slaves & masters are all the same for all the corvettes with the zf6 option. I tried looking on my parts CD and the only difference I can find in P/N's is the 90 slave with the bleeder at 11 o'clock is a discontinued part....but we all know that. The 91 & up slave replaces the 89 - 90 slave cylinders due to bleeder position.

I would check with Bill at zfdoc.com as I never remembered hearing about two different slave cylinder bore sizes. Sorry that's all I have to add on this subject.

:cheers:
Tom

[-=Jeff=-]

did you take them apart and check the inside bore?

the Left one is thinner walled DOM

the right one is a Cast part

I am using the one on the right FWIW

[mike100]

thanks for the thoughts. I put it on and am just waiting for a helper to get it bled tomorrow. I'll take it apart when I get the new one working (hehe-don't want to leave myself with no options).

the old one was wet on the seal end.

[XfireZ51]

Using cast iron slave. Works great. May need longer mounting studs.

[tomtom72]

Mike, just as a follow up to this bore size question. I doubt that there are two bore sizes as I have transplanted the guts from cast types into the OEM/DOM type...piston + seal + spring and have even swapped rods & ring retainers.

FWIW, the cast types use a different piston seal configuration than the DOM type. No micro ridges on the F-Mogul seal as it has broader shoulders for more bore contact surface thus no meed for micro ridges.

:cheers:
Tom