I'm trying to rebuild the right rear brake cylinder and can't figure out how to get the metal disk off so I can replace the rubber piston cup without destroying the metal disk.

Could someone please help me out?

Thank you!

What metal disk are you talking about? Is there a disk in your picture somewhere? Everything looks black... Can't make out any seams.

Are you talking about the piston itself maybe? The part that the rubber seal slips onto?

Datsun 240Z/260Z/280Z Rear Brake (Drum Brake) (To Jul.-'76)

The Service Manual is always useful. Better drawing too.

Looking at the pictures and having worked on similar things, I think that the seal you're trying to replace just slips off over what you're calling the metal disc. The "metal disc" is actually the top of the piston (as CO suggests above). It's all one piece. Slip a thin screwdriver or pick under the rubber and it should peel off. It's doughnut shaped.

Edited July 7, 201410 yr by Zed Head