Brake Servicing

[StumpyFingers]

First thing you need is a nice warm workshop.
Next make sure you have everything you need

When ready remove the blanking cap.
then loosen the pin:
You can then remove the caliper from the bike.
Fully remove the pin and pads and springclip from the caliper.
Then Either using the brake lever or if you disconect the cailper hoese Air pressure to pump out the pistons

This image shows the Seized piston in its origianal position and the piston being pumped out.
Next remove the seals clean the recesses and replace the new seals
the right side shows the front seal .
Ensure the new seals are seated correctly then insert the new pistons.
They are tight but with care can be tapped into the caliper. then reassemble the caliper as you would when changing the pads.
Now all that is left is the process of bleeding the system.

[olionel]

Hello;

Can someone list the bits that are needed for this? I can't make out what everything is on the table.

Thanks very much in advance
Oliver

[Betterl8thanever]

Oli,

You are looking at new:

Pistons,
piston seals,
piston dust seals,
brake bleed nipples,
brake fluid,
length of tubing for brake bleeding.

All available from Wemoto as a kit or as seperate items.

Make sure pistons come out together by restricting the more free one with a screwdriver or similar. If one pops out and the other stays stuck you will have to wrestle it with mole grips or insert old piston and bleed/try again.

good luck, just done mine.

[Warthog]

To get a seized piston out, as described above, you want to immobilise the free piston, then work the lever so that the pressure then pushes the seized piston out. Once it is someway out, keep pumping gently. You'll see the pistons pumping in and out by a couple of mm with each pump at the lever.

When both pistons are out so far that you'd only get about one brake pad in the remaining space, then I suggest you stop with the lever. At this stage, make sure there is a container under the caliper and cover any nearby paint-work (brake fluid attacks it). You can either remove the pistons by hand (wear gloves), or using plumbing grips as they are narrow, but have a nice wide diameter. If you use the latter, I suggest using a piece of heavy material or even a strip of leather that you can grip with out the risk of scoring the piston surface.

The times I have done my brakes I have washed them thoroughly in soapy water, then dried them fully: on a radiator, or even in the oven at 50C (remove all the seals).

Reinsertion is quite easy, but don't rush as Stumpy said. You can lubricate with some brake fluid if you want, but make sure you rinse the caliper afterwards (once all holes have been sealed, or the caliper has the hose reattached to avoid water ingress!!).

[Mervinh]

If your pistons are rusty replace with stainless steel ones if possible , a once in a lifetime upgrade that you will not regret
merv