Slide off the clip by tapping each leg with a hammer and screwdriver.
The base of the cylinder projects through a slot in the backplate, in which it is free to slide.
Outside the backplate two interlocking spring clips, pushed on to the projection from opposite sides, hold the cylinder in the slot.
Sometimes there is a single spring plate with two non-springy clips. There is usually a dust cover to seal the slot.
Pull back the dust cover. If there are two spring clips, slide off the outer one by tapping each of its two legs alternately a short way with a screwdriver and hammer.
Slide off the inner clip in the opposite direction.
Sometimes you have to remove the handbrake lever arm so that you have room to remove one of the clips.
If there are two clips under a spring plate, slide the clip next to the handbrake lever as far towards the lever as possible.
Push the other clip in the same direction until you can ease its end under the spring.
Push the first clip down to lift the spring off the second clip. Pull the second clip free, and lift off the plate and the first clip.
Again you may have to remove the handbrake-lever arm or bleed nipple to free the cylinder from the backplate.
Clean both sides of the slot in the backplate and smear with a little brake grease. On reassembly make sure the dust cover fits properly and securely so that no dirt or spray can enter and cause the cylinder to seize.
Removing the brake pipe