Refurbing calipers - do I use sealant on the piston seal?

[Bennet]

I'm refurbishing some calipers this weekend. (As in, disassemble, clean, reassemble with new rubber bits.)

Haven't done this before. When installing the new rubber seal on the piston, do I need to add sealant of any kind to make sure it seals properly? Some videos mention this, and some don't.

If so, any recommendations for what to use?

[TimmyMallett]

Red rubber grease I thought?

[E-bmw]

It is not a sealant, but yes, as above red rubber grease is generally the go-to assembly lubricant of choice.

[Bennet]

Red rubber grease it is then. Thanks.

[richhead]

you can get special seal conditioning fluid, but dont bother, just leave to soak in brake fluid over night, and never, never, never use grease on brake seals. especially rubber grease........
brake fluid is all the lubricant it needs, why would you use something that it never sees in service., makes no sense. grease also boils way below the temp needed in brakes, causing gas bubbles, not what you want on brakes.
anybody recommending using anything other than seal conditioning fluid or brake fluid on a caliper rebuild, is someone to avoid.