So my mum and dad had a tandem. I kinda inherited it earlier this year when me dad passed way. It has a rear hydraulic disc brake, which has been playing up. I get it into the garage and services the brakes, finishing with a good bleeding through.
All this preamble is to set the scene for the photo below… some clean dot4 at the top with the gunk the brakes flushed through (seen at the bottom of the jar) a rank, spongy liquid pretending to have none compressible qualities… it’s got to that condition from years of not being changed… contaminants infiltrating and ageing brake-down (excuse the pun) of the oily liquid.
Just a thought for those of us in between the new bike dudes and those with cable operating brakers… when did you last have yours bled???
Worth mentioning that not all bicycle hydraulic brakes use DOT fluid. The big names such as Shimano and Magura use their own stuff usually and deviating from it will invalidate warranties and possibly damage seals. Most of them use mineral oil to their own spec to make sure you have to buy from them. Well fancy that…
A good point @DCS222 and well worth taking note of.
Also worth reading up on fluids and which one required. Dot 4 is ok with Dot 5.1 but not with Dot 5.
Topping up the master cylinder or reservoir isn’t a good idea unless you really know what’s already in there.
On the speed triple (and before it was traded in, the street triple) I change it every two years. The two others still have warranty, so the dealer does those on the appropriate intervals (I assume…). And as those both have ABS that’ll stay that way, I think.
I bleed the brakes partially once a year, fully every 2 years.
And I found a way to make it really really easy. I installed some “Stahlbus” bleeders (with a built in spring and steel ball). Honestly worth the price for the ones doing self maintenance on the bike.
