Replacing (or not) brake wear sensors

[21TonyK]

So discs and pads need changing but the sensors aren't showing anything yet. Can I refit old sensors if they aren't "activated" or will I take them out and they are part worn and not work correctly with full thickness pads?

[Polly Grigora]

As long as the relacement pads are of identical thickness to the worn ones they will go again

[paintman]

What type of sensor have you got?

I'm curious as the ones I've seen on our own cars are basically a loop of insulated electrical wire in a little plastic plug pushed into a hole in the pad.
As the pad wears thin the wire insulation wears through & the bare wire can make contact with the disc thereby putting the warning light on.

Whilst I could re-use any that still have the insulation intact I just use the new ones that come with the new pads.

[Matt_E_Mulsion]

Its false economy not to replace the wear sensors in my experience. The chance of the fiddly little things breaking their circuit whilst you are trying to remove them and refit them, plus expecting them to last as long as another set of pads when they've already done a duty cycle - the odds are not in your favour. They are relatively so cheap why would you not replace them.

[E-bmw]

As above, they tend to either break or the spring will fly out rendering them useless anyway, false economy in time if nothing else.

[Dave Brand]

Replacement pads should have wear sensors already in place.

[ChocolateFrog]

Dave Brand said:

Replacement pads should have wear sensors already in place.

Both audible and visual sensors stat firmly in my head between pad changes.

[Smint]

Pretty sure the last time i replaced pads on my old MB it came with new sensor leads, if not they're cheap enough to buy but if you remove them carefully should last a couple of pads out.
If its those spring clip types that scrape on the disc when pads are worn enough, they've always been supplied with new pads in my experience.