Just thinking - My Hope mono mini's on my Orange haven't been bled for over a yr. They are working fine, but will the fluid have taken up air such that I am heading for a catastrophic failure just when I need them ??? 😀
I do have some unopened fluid, so a bleed wouldn't take me long - oh, and roughly how many 'reservior fulls' to flush front and back respectively ?
If they feel OK then they're OK.
I imagine the vast majority of 20 year old cars have 20 year old brake fluid in them.
They won't fail, they'll just get spongy. Every couple of years is ideal but they can go much longer.
Yes - you get both water and dirt ( dust coming past the seals and wear particles) accumulating in the fluid which increases wear and decreases boiling point. Its good preventative maintenance to change the fluid every year or so. Take five mins and costs pennies. You should be able to see the fresh fluid come thu in the bleed tube but IIRC its about 3 reservoirs full
thanks all
OK - so took advantage of a spare hr and bled them. The old fluid was definately a bit grimy compared to the new. The most surprising thing was that when I took the reservoir caps of there were some small beads of condensation on top of the diaphragms on both sides. That particular bike hasn't been used in a month right enough and lives with the others in a cool and dry integral garage.
Also glad I did it as the diaphragms were kind of getting stuck to the caps - reckon I might have struggilng to get the front one apart if I had left it.
Preventative maintainance indeed 🙂