4-Wheel Brake Sensors - Easy or a Silly Idea?

[T-Cut]

It's often been been said that having only the offside brakes fitted with wear sensors doesn't really give the best indication of overall pad wear.
It occurs to me that converting it to a 4-wheel system might be relatively simple - that's if I have the gist of it right.

The wear sensor circuit is just a continuity loop if I remember correctly, so two more sensors could be inserted into it and you could have 4-wheel sensing. So fitting a sensor to the nearside brakes seems like an 'easy' wiring job, or is it?

Could someone with an intimate understanding of the OBD and brake sensing point out the obvious problem?

[Lates]

Unless the car has problems, I have yet to see a ZT/75 with pad wear that far out for example it ruins discs. Regualr routine maintenance is the way to go imo.

[Dragrad]

As a matter of interest, are the existing sensors on the inner or the outer pads?

Personally I have a look at the pads, if they look low, I change them. Don't trust sensors... old fashioned visual inspection seems the best way to check your ability to stay on the road

[T-Cut]

Originally Posted by Lates

Unless the car has problems, I have yet to see a ZT/75 with pad wear that far out for example it ruins discs. Regualr routine maintenance is the way to go imo.

I agree completely, but that's not what I'm on about. There are frequent comments that other cars with brake wear monitoring do it on all four wheels. Clearly, there's a logistical aspect to it. If you wish to monitor at all, why not monitor each caliper? From a purely theoretical standpoint, would it work?

[Lates]

Cannot see why it wouldnt work but me and electrickery bits dont always see eye to eye

[T-Cut]

Originally Posted by Dragrad

As a matter of interest, are the existing sensors on the inner or the outer pads?

They're fitted to each inboard pad on the front and rear offside calipers. The inboard pads on the nearside calipers use the same pads, so they have an unoccupied sensor slot.

It's not unusual to read of people finding one front or rear caliper wearing the pads at a different rate to the opposite caliper. The argument for 4-wheel monitoring seems stronger than 2-wheel monitoring. I believe the V8 brakes only monitor one caliper (front offside I guess). The logistics of this escapes me. I realise the design principle says that pads on any axle will wear at the same rate, but that's patently not so in reality. If a wear system is to be use at all, logic suggests that all brakes need sensing. On the other hand, if regular visual inspection is recommended over an automated system, why have such a complication anyway?

[Dragrad]

Originally Posted by T-Cut

They're fitted to each inboard pad on the front and rear offside calipers. The inboard pads on the nearside calipers use the same pads, so they have an unoccupied sensor slot.

It's not unusual to read of people finding one front or rear caliper wearing the pads at a different rate to the opposite caliper. The argument for 4-wheel monitoring seems stronger than 2-wheel monitoring. I believe the V8 brakes only monitor one caliper (front offside I guess). The logistics of this escapes me. I realise the design principle says that pads on any axle will wear at the same rate, but that's patently not so in reality. If a wear system is to be use at all, logic suggests that all brakes need sensing. On the other hand, if regular visual inspection is recommended over an automated system, why have such a complication anyway?

I hear where you are coming from, and it makes sense.... As the sensors are fitted in-board, then a cursory visual inspection would not work. Pads on the outside can, and invariably will wear out less than the inners (in my humble experience). So it makes sense to have the sensors on the inner side. However as you suggest, pads on the same axle never wear evenly.... So, Yes, a four way sensor system would make a lot more sense.

In my past... if I can see the outer pad worn down to the last 2-3mm then I always take the wheel off and have a look at the inner, unless up on a ramp for whatever reason. But then again, if they are worn down that much... it's time for a change

As a matter of note, my old Nissan Sunny which I had for three years or so and did about 600 per week always wore out the off-side pads a lot faster than the nearside. same went for the van (13 years).... Maybe had something to to with my weight?

[Greeners]

...............................so presumeably you just plan 2 add two extra sensors into the existing circuit...?

[sworks]

Not had much to do with the sensors but I think the harness is checked for resistance. As the pads wear down there is a little raised section that wears away on the sensor which in turn puts the light on. If 2 extra sensors are fitted the resistance would change within the circuit and I think may illuminate the light in a similar way to fitting led's in the light units. Only a guess though!

[workaholic_ro]

Originally Posted by T-Cut

Could someone with an intimate understanding of the OBD and brake sensing point out the obvious problem?

Easy and not a silly idea.:lol:
Don't bother about OBD or any other fancy protocol. As you said, the sensor circuit is just a continuity loop. The sensors are nothing else than glorified plastic coated wires. A series connection will fool the ECU which will never know that you have two sensors instead one. If there is, for some reason, a resistor included in one of the connectors (which I doubt, but easy to investigate anyway), one of them will probably have to be removed.