Technical Brake disc, a ring of rust

[Pugglt Auld Jock]

The new discs have made zero difference to braking performance. How odd.

Hmm, interesting. Is that braking performance as perceived by you in daily driving, or, that recorded for individual wheels under maximum braking effort on a brake testing machine - as in MOT rollers?

 

[AndyRKett]

If these are the back discs then you have to remember the majority of the stopping is done on the front, the rear brakes largely just stop you facing the wrong way after an emergency stop

 

[Pugglt Auld Jock]

If these are the back discs then you have to remember the majority of the stopping is done on the front, the rear brakes largely just stop you facing the wrong way after an emergency stop

exactly what was going through my mind.

 

[Tipotwo]

Hmm, interesting. Is that braking performance as perceived by you in daily driving, or, that recorded for individual wheels under maximum braking effort on a brake testing machine - as in MOT rollers?

In normal driving, which is me and my son and includes an emergency brake that set off brake assist.

 

[Pugglt Auld Jock]

In normal driving, which is me and my son and includes an emergency brake that set off brake assist.

So what Andy said above applies absolutely:

If these are the back discs then you have to remember the majority of the stopping is done on the front, the rear brakes largely just stop you facing the wrong way after an emergency stop

The harder you brake the less influence the rear brakes have. Indeed many vehicles have brake apportioning valves which are there solely to cut down on rear braking effort as you increase the pressure on the pedal and weight transfer causes the rear tyres to have less inherent grip thus stopping them from locking up under heavy braking. I think you could argue that most rear brakes act to stabilize the vehicle under braking and as a parking brake and have little to contribute to overall total braking effort - Maybe a little more in a heavily laden vehicle? Under normal "gentle" driving conditions I doubt if most people would notice if the rear brakes were disabled entirely?

 

[Tipotwo]

I hated the ring of rust and now the car will not risk another MOT advisory or even failure, so for the cost, it was still worth it.

 

[aschiuta]

So what Andy said above applies absolutely:

The harder you brake the less influence the rear brakes have. Indeed many vehicles have brake apportioning valves which are there solely to cut down on rear braking effort as you increase the pressure on the pedal and weight transfer causes the rear tyres to have less inherent grip thus stopping them from locking up under heavy braking. I think you could argue that most rear brakes act to stabilize the vehicle under braking and as a parking brake and have little to contribute to overall total braking effort - Maybe a little more in a heavily laden vehicle? Under normal "gentle" driving conditions I doubt if most people would notice if the rear brakes were disabled entirely?

Wrong disscution. All active safety options on car, like ABS, ESP and so on, rely on brakes and tyres.
So you want the braking system to be at top level functioning.

 

[Pugglt Auld Jock]

Wrong disscution. All active safety options on car, like ABS, ESP and so on, rely on brakes and tyres.
So you want the braking system to be at top level functioning.

Ha, ha. I wasn't for one moment suggesting the rear brakes could be done away with! Just suggesting that the rear brake condition contributes little to the driver's perception of overall brake performance under normal conditions and use. This person's rear discs looked pretty horrendous and, if they had been on my car, would have been changed long before they got to look like that!