Changing brake fluids

[stants]

Cap states dot3 which has been replaced with dot4, i'm guessing that's what's in there now, will I have any problems just replacing with dot 4 or even dot 5.1 ?

Or do I need to flush out with anything 1st, last thing I want to do is rot the insides of my system

[tom_gr7]

I have Shell dot 5.1 in mine, Seems to be ok.

[Jay762]

Dot 5.1 will give higher tolerance to heat and any moisture ingress. Used the Shell product for years on bikes and cars would recommend it