thanks all
It would probably help if I didn't ride in torrential rains and ford streams on a regular basis as well as washing the bike before i put it up but that's just the weather we've had this year. (up until 2 weeks ago)
Still going to go with the used caliper (with like new pads, bracket and arm included) for $55 (£ 41)
A refurb Unit here goes for $81 (£ 62 ) and it's from the UK but it's exchange on the old one and does NOT include brake pads.
So roughly double the cost of a used one.
If I can get 3 years out of this one (got a used one last time) It's still cheaper and loads easier than redoing one on a yearly basis.
Think I will order the kit and redo one of the old ones so i'll have an extra one on hand for the next time.
Having a spare ready is certainly a good idea......
Just my luck the bike will be down for a bank holiday weekend with perfect weather in the forecast.
The caliper is of course scheduled arrive on Tuesday, the day i go back to work.