Rear Coilover Knocking.

[Rushy21]

My left rear coilover is making a knocking sound when going over bumps sometimes. It also makes the sound when I push down on that side of the boot and 'bounce' the car.
I put some lubricant on it and the noise went away for a day or so, and now its back the very next day.
I took the whole thing out and installed it again, but it still knocks.

The left right coilover makes no noise whatsoever.

Edited November 1, 2013 by Rushy21

[GH05T]

probably nackered and will need rebuilding if possible, what type of coilover is it?

[Rushy21]

GAB I think, they're red.