Technical Brake pad wear sensor system not working? 0.9 TwinAir 85

[Multivide]

Hi folks I'm new here


(After some searching I couldn't find an answer to my issue)

My girlfriend recently bought a used 500 0.9 TwinAir 85 from 2012 and when swapping tyres I noticed the front brake pads were pretty much gone.

I put in new disc and pads, and noticed the pads actually come with a wear sensor, as did the old ones. BUT there was never any warning light.
I then tested the old sensor by stripping the wire, clamping the copper leads directly on the new brake disc, and turned the car on - still no warning light.

So is the integrated system to actually give a warning about brake wear some kind of extra equipment, or is the system faulty?

I should mention I only tested it in the left-hand side (drivers side over here) after cleaning the connectors. Everything LOOKED fine and clean.

 

[jackwhoo]

Sometimes the pad warning light is the same light hand brake warning light.

Unplug the the pad wires Check for electrical continuity between the two wires connected to the pad material. If there is continuity maybe the pad has to wear out and cut the connection between the wires to activate pad wear light.

What ever happens I hope if the pads wear out without a warning light again your girlfriend will be alerted to the problem by hearing a load grinding noise!

Do you have annual vehicle inspections in Denmark?

 

[chris3234]

Unplug the wear sensor at it should bring a light on
Most of them work by bringing the warning light on when the circuit is broken at least in my experience

 

[John202020]

If I remember correctly the wear sensor is a single wire that earths when pressed against the disc face, I'm pretty sure ours might be broke or the inside pad is stuck and not worn as much sure ours is desperate for new pads need a warming day

 

[John202020]

Yep just one wire on ours, the sensor wire pushes in the top hole of the pad(not pushed in fully for now)

 

[Baglady1990]

Mmmm I had / maybe even have the same issue on my 2011
Amongst other issues when I bought the car the brake discs & pads were shot! I had no warning light either!
Will investigate also

 

[John202020]

The pads that are on at the mo has the sensor wire "in" the pad material not like the new ones, so if they wear unevenly the pad without maybe non existent and the one with say 3mm?

 

[Multivide]

Sometimes the pad warning light is the same light hand brake warning light.

Unplug the the pad wires Check for electrical continuity between the two wires connected to the pad material. If there is continuity maybe the pad has to wear out and cut the connection between the wires to activate pad wear light.

What ever happens I hope if the pads wear out without a warning light again your girlfriend will be alerted to the problem by hearing a load grinding noise!

Do you have annual vehicle inspections in Denmark?

Incredibly there was no grinding noise this time, but half a mm more and there would have been.

We have car inspections every 2 years here in Denmark. Would have been interesting to see how well it was braking (in actual numbers) since the surface area was greatly reduced

Thanks for all the answers guys. Can confirm the wire is embedded in the pad material. I will try some testing later today when we're both back home.

 

[jrkitching]

I'm not a fan of 'wire in pad' sensors. They give a false sense of security, as it's often a pad without a sensor that wears out first, and there are plenty of other ways they can fail to activate even after the pad has become dangerous (a pad sticking in the caliper is one example of how this can happen).

They should never be relied upon as a substitute for regular inspection of the brakes; to do this properly, you need to remove the wheels, and check both sides of the car - a lot of franchised dealers only check one side.

The equivalent Panda doesn't have pad wear sensors, and the pads are about £10 cheaper because of it. They're identical to 500 pads in all other respects.

 

[typecastboy]

As has just happened in my Abarth. One piston was jammed solid and the brakes were binding and squeaking one side. The pads were almost on the metal on that side but the sensor was on the other side and those pads were not binding so were not worn right down.

 

[John202020]

If you could get the sensor on its own then in theory you could put them in all 4 pads and wire them back to the single sensor wire? Or just keep an eye on them?

 

[jimboy]

I'm not a fan of 'wire in pad' sensors. They give a false sense of security, as it's often a pad without a sensor that wears out first, and there are plenty of other ways they can fail to activate even after the pad has become dangerous (a pad sticking in the caliper is one example of how this can happen).

They should never be relied upon as a substitute for regular inspection of the brakes; to do this properly, you need to remove the wheels, and check both sides of the car - a lot of franchised dealers only check one side.

The equivalent Panda doesn't have pad wear sensors, and the pads are about £10 cheaper because of it. They're identical to 500 pads in all other respects.

Yes this. Spot on.

 

[John202020]

This is a perfect example why not to trust the wear sensor on the plus side my discs and pads for £24 the discs are coated/painted even better value!