I’ve just bee trying to bleed my formula k18s. I’ve attached the syringes, got the lever vertical in a vice, and the caliper bleed screw vertical too, I can’t get the fluid to pass through to the master cylinder, when I push it becomes won’t move, pulling in the m/c syringe doesn’t help either. I pushed hard enough for the hose to come off the caliper mount and spray fluid everywhere.

They’re about 6 years old and have been playing up with sticky pistons for a while so I am tempted to bin them. Before I do does anyone have any top tips for getting round this?

Cheers

John

Do this you might have to zip tie the lever back as well

They’re the instructions I followed. The fluid just won’t move through and a piston is still stuck.

I recently overhauled my K18s with new pistons and seals. They are now fantastic again. Had to drill the old pistons out though as they were well stuck (drilled a small hold in one diagonally the used some small needle nosed pliers to get it out).
Took a couple of attempts to get all the air out afterwards but they are good as new now! Much cheaper than new brakes.

I think you need to sort the sticky pistons first.
I ‘un-stuck’ mine by pumping the brake with no pads in so the piston came out a little bit, then wiping the piston with a bit of brake fluid on cotton bud, then push the piston back in. Did this a few times and they started to move OK.
You need to be very careful not to pop the pistons al lthe way out though.
Although Formulas are great brakes (when they work properly) I do think they like regular fettling – I’ve resigned myself to bleeding/servicing mine every year, wheather they need it or not, just to keep everything moving.

I had tried that method of in sticking the piston, it will only come out about 1mm. I’ve managed to do it before but this time it’s just not moving. I think it’s just worn out over time. It’s on my winter bike so it regularly gets covered in filth and I think it’s finally taken its toll.

If you can’t push fluid through, something’s obviously blocking it’s passage, and there’s not really a lot bar the master-cylinder piston that’ll do this. Is your lever depressed, or it’s pushrod stuck down? It only needs to be pushed in a touch before it locks off the reservoir.

As coatsey said above. Also, have you definitely got the o-ring from the calliper bleed port out. This can fold over and block the port if not removed. Just checking….

Good point about the o ring, I’ll check that tomorrow.