Baggy rear brake problem

[scholsey]

Once again I am looking for some help or advice, I think the rear brake cylender has blown ... this is the grey metal part that the foot brake connects to to pump the fluid to the rear caliper. It is leaking slightly and wont pump the fluid to the caliper. I have disconnected the brake hose at the caliper end and its justs spits a little but does not have a continued pump of fliud. Are these able to be fixed or where would I get one from ? or what boke is this part compatable with ?

Just had it MOT 'd and taxed but now cant ride it ....................................

Andy