Just thinking the other day about doing the 312brake disc upgrade.

It occured to me about the warning system for low brake pads

a, how does it tell when the pads are low anyway

b, if i fitted the 312 calipers would they still have the warning system in place?

The wires for the warning system are buried in the pad material. When you reach this point, they touch the metal of the disc and make a circuit which illuminates the light. - Simple really.

They aren't used on the Fabia and so you just snip them off.

they are used on the fabia?

Beg to differ mate - didn't have them on my VRS.

Still got the bit of wire I cut off in my tool box.

oh, i always thought it did, im gona go read up now lol

Easy to tell - look in the wheel arch for a cable running to the pads. It'll more than likely only be on the one side. Don't confuse it with the ABS sensor.

They dont use pad wear sensors on the Fabia as it only operates on fixed servicing.

IMO Pad wear sensors are so god damn cheap, ALL new cars should have them.

I had a Megane with 20,000 mile service intervals. They failed to tell me at service that the pads were down to 20%. 4 months later I had rather crappy brakes, and I needed disks too

Jesus... on a car that has a warning sensor for the rear seat "not quite latched in properly", why not have a "brakes will fail soon" sensor...

Because it gets serviced every 10k and brake pads get inspected.

Also if the brake fluid level is low the light comes on.

Because it gets serviced every 10k and brake pads get inspected. Also if the brake fluid level is low the light comes on.

Whilst I appreciate that might work for the person who does nothing between services (would you believe one of the Directors at work didn't know how to open the bonnet of his Toyota, since he never checked the oil level) I believe all cars should have some sort of warning system on brakes even with fixed service intervals.

My 1990 Citroen XM - with an electronic warning system - went through THREE services (admitedly at a 6,000 mile interval) with me being told at EACH of these services that the front brake pads needed replacing. I realise that if it's borderline they'd have to advise replacement but this was something else.

Hence before my Fabia gets its 20,000 mile service I'll be inspecting the state of the pads. I don't want to have to get them to replace pads at 20,000 if in reality they might last to 29,000 or beyond...

Would someone please post the minimum pad service thickness. My MX-5 works to 1mm whereas the Freelander that preceded the Fabia worked to 3mm.

The warning light is connected through an electrically conductive carbon insert in the pad. When it is exposed, it makes an electrical connection to earth through the disk. Works like carbon brushes in a motor so it is self-sacrificing and won't damage the disk or impair braking once the pads wear down to expose it. That is provided you do something about it before you start grinding metal.

Strangely many cars don't use them and they just get cut off. Essential on at least one side front and rear (if you have rear disks) IMO if your car has variable servicing.

IIRC spec for the front pad is 7mm min thickness including the backing pad.

And DRJ you are quite right about the brake pads being done early as they 'may' not last to the next service. Its a difficult call to make for a techie, this is why if im not sure i'll advise a customer to pop back say in 5,000 miles and i'll re inspect the pads (inspection with no charge of course, just the labour to change them if required).

Pad sensors are all well and good but they usually wear through when there is a good few 000's of miles left on them anyhow.