Breaks!

11th hour faffing about with my Shimanao XT hydraulic brakes on my Specialized Epic MTB. They felt a little spongy at the lever, so I made an attempt to bleed them. Shimano hydraulic brakes use ‘Mineral oil’ as apart from your regular brake fluid with other brands like Avid or Hope, so that meant a visit to my local bike shop with my quacking wallet in hand.

Shimano hydraulic brake mineral oil was about $35 sold in 1litres bottles. A re-bleed of both brakes would only use about 100mL thereabouts, so the investment in the full bottle would take a few years to recover. Lucky for me my Local bike shop fella could see the doubt in me set in as he handled the bottle & offered to pour me 200 odd mL into a separate container for $5 – phew.

I love working on Shimano hydraulic brakes; the pads come out & drop in easy, the pistons push out to accommodate new (thicker) pads without effort, the pistons retract well after application at the lever so the pads have room to back away from the rotating disk when it use (no dragging), & no special tools apart from the cassette tool for the centre lock rotors.

Back home, the bike is hoisted up on the (homemade) bike work stand, I pop the brake reservoir cap off & place a length of tube on the bleed nipple on the rear calliper, then i extract what I can of the oil in the reservoir & top it up with the new stuff. The existing oil is almost clear, where the new stuff is is blood red, not sure if this means anything. I open up the bleed nipple & pump the lever to draw the new oil down into the brake line, being careful not to empty the reservoir & draw air into the line (that’ll mean a long night if I did).

When I finished & could see the dark red oil coming out the clear tube connected to the bleed nipple on the rear calliper, I top up the reservoir, popped the reservoir cap back on, & removed the clear tube off the nipple. It’s at this point when I am removing the clear tube off the nipple on the calliper, that a stream of brake oil drained out all over the calliper. Sure I grab a rag & wipe it down but apparently that wasn’t enough.



Two days later it’s time to ride the Epic to work & then onto the dirt crits afterwards. As I get to the end of my alleyway the rear brake squeals something chronic & I realise that a good percentage of brake oil has affected the brake pad. I try to not worry about it & let it fix itself, but the whole trip into work it’s squealing, & even thought the lever is firm, it feels like I don’t have the kinda braking I was hoping for out back.

So come lunchtime I head back downstairs to suss out the brake & remove the pads with a multi-tool. The pads are pretty worn, but also pretty dark for oil contamination, so I opt out of refitting them & pick up some new pads for a CBD bike shop & bung them in.

Will be crossing the fingers as I roll off this evening...