I went to change the brake pads on my motorcycle, since they had not been replaced in a while i needed to depress the pistons in them to fit the new ones over the rotors, but now that they are back on they will not engage, this is happening on both the front and rear. i stood there for hours pressing them hoping to maybe prime them or something. all the reservoirs are full, what do i do?
Make or model would help. How did you depress the pistons? Did you clean the pistons before you depressed them? Is there any feel of pressure at the lever? Are the hoses bulging at all? Did you route the hoses correctly when you reassembled the calipers? Did you open the hydraulic circuit, replace the fluid or anything? Brakes can take a few pumps to reposition the pads against a disc – but not hours. Caliper rebuilds are fairly simple – a new bleed nipple, couple of seals and piston(s), so are master cylinder rebuilds – however if you have any doubts a professional would be a better choice – brakes are quite important.
Remove the brake caliper and pads put a piece of wood or a tool in the gap where the pad were and work the brake, and look to see if the piston is moving out of the cylinder. The wood or tool will just stop the piston completely being pushed out of the housing.If it comes out just loosen the bleed nipple and push the piston back in. With the bleed nipple loose it should be easier to push the piston back. If not it may be seized up and need reconditioned or renewed. Some times you can pull back the rubber boot and spray some CRC around and clean it. Most seals now will not be harmed by it as it is not rubber like years ago.
the calipers are likely old and tired and you may need to replace them with new ones. after years of work it sounds like replacing them is going to be your only option. I know they may sell rebuild kits. but I have never seen anyone successfully do it right. And suggest once you replace tham and bleed them they will work just fine and last the lifetime of the bike.
