Brake fluid Dot 4 ok to use?

[SteveW]

Just stripped down the siezed front brake on the 550, noticed the reservoir cap says Dot 3 only.

Can I use Dot 4?

Not sure I've ever seen Dot 3 for sale.

[hairygit]

Yes, and if the whole brake system has been stripped/re sealed you can use DOT 5, which is silicone based, and it doesn't strip paint if you get it on your tank, and is not hygroscopic either, which means it doesn't suck moisture from the air, which means you wont get a rusty caliper piston. 

[SteveW]

Thanks very much.

The master cylinder seemed to be okay when i was pumping the seized piston out but I'll probably rebuild that as well due to the age of the seals.