Trying to ease the pistons back on formula oro…I have read that a bit of hydraulic brake fluid on them can help with this?

Yup, give them a liberal squirt of brake and clutch cleaner first and poke a cotton bud arround the piston to remove any dirt.

A thin smear of DOT fluid compatible rubber grease helps as well, I think Avid sell it, or you can get several lifetimes supply from halfords (Castrol Rubber grease, it’s bright red silicon based grease with clay in it so you can’t mistake it for the wrong stuff).

I think I’m the first diy mechanic in the world to have to buy a second tub of rubber grease. Drove over the first one 🙁

TBH though if the piston’s very sticky, it’s often not going to help, it’s a bit like trying to fix a rusty bearing by adding grease. Especially with an old brake. Stcky pistons are often savable with a strip and clean though.

(if it doesn’t work out, I’m sure I’ve got a spare oro piston somewhere)

Stuck piston?
Has it just stuck? or have you just replaced the pads and found that the pistons will not backoff enough?

http://singletrackworld.com/forum/topic/replacing-formula-oro-pads-is-it-just-me

http://singletrackworld.com/forum/topic/formula-rx-brakes-piston-not-returning

Some tips from Hope for hope brakes might work for Formula brakes

Thanks for all the pointers.

Presently riding with one new and one old pad each end and there is still a lot of drag with no sign of it easing up after 1 week, makes it even more enjoyable riding in to a headwind!

Macavity…..new pads, whilst old pads were still in place a big screw driver was used to push the pistons back, they’re just not sitting quite flush though, only very slightly mind.

Brakes were second hand off here so possibly bled before I acquired them with worn pads. New pads could be thicker than the ones they are replacing.

Can anyone point me in the right direction of bleed port that needs opening to let a some brake fluid out so pistons can retract a bit more (hopefully!)?

On Oros it’s in the caliper banjo bolts IIRC. A wee torq, don’t use the wrong size, unhelpfully I can’t recall the size- T12 or T15? Doesn’t need to come all the way out, just back it off while spreading the pistons and release a little and it should leak past the screw.