Took the brakes of my bike, removed the pads and gave the inside a spray with.....wait for it....carb cleaner, on refitting brakes the pots have almost seized up

I can only assume due to using carb cleaner rather than brake cleaner (thought it was the same thing) anyway, how do I resolve this issue ???

Easy fix, pop cover of master cylinder, push the pistons all the way back into the caliper until they bottom out flat. re install on bike and pump the lever until the pistons come out and compress the pads onto the disc. Maybe they just need to be "forced" to move a bit.

Extreme fix would be romove brake line and split the caliper. Use compressed air to "POP" the pistons out, ( careful they will fly!!) inspect and replace seals and pistons if necessary or re lube everything with brake fluid and put it all back together.

These pots aren't shifting with or without the cap off.

As for splitting the caliper, that's not possible as it's a one piece forumla, and even if it was, I wouldn't, been there done that, nightmare that it is.

Are you saying the pots appear have seized solid when you try to press them in by hand?? or when you use the lever / hydraulics to push them out in the normal way??

Its common for pistons to rock slightly, and jam, especially if they are a long way out of their bores.

If i were you (and assuming the pistons still move with hydraulics), i would pump the pistons out quite a way and wet the sides of the pistons with brake fluid. The fluid will "wick" around the piston / bore area and wet the outer piston seal. I would then use a large screwdriver between some old pads (or similar thin flat material) to press the pistons back fully in as the previous post suggests.

This way, the seals will be "lubricated" on the outer and inner edges and the pistons should move freely, however this is often a short term fix.

Last point... as previously stated there is no substitute for removing the pistons completely and cleaning / lubricating the pistons; bore and seals. "Popping" the pistons out using the hydraulics or air is the normal way to do this. Some solvents cause the rubber seals to swell and increase the stiction on the pistons (sounds like this is the case), this will require replacement of the seals which are not expensive. If this has been a nightmare previously then i suggest the help of your local motorcycle mechanic.

Dom

Edited March 23, 201313 yr by dombush

No idea what you have done here really? You say they will not move and you have good lever pressure?

I agree with Dom on most all this, only other thoughts are the cleaner has swollen the seals soo badly things are stuck.

No idea exactly what is in the Formula caliper, yet it seems there is a removable lid in the side of the bore. Might ask Splat Chris to get a guage on just how screwed you are?

I'd agree that the seals are swollen to the extent they ain't moving much at all now, in fact probably only one of them out the four is moving.

I have tried to grease them with rubber grease but not making much oddsa, next step is to try and get them out I guess.