Should a pad sit like this?

OldMrBrennan83

The gap at the far side I mean.

Stoolbend

I’m guessing that gap is just the normal taper on the pad surface.

Did you inspect the discs inside and out when fitting the pads?

rex-x

Your discs are totally shot, they should have been replaced with the pads

Turbohymac

Theres a lot of wear on that disc by looking at the sharp edge on the outer side.. discs need more attention than pads..sometimes just throwing in pads don't fix the very worn glazed discs.. go to main dealer if possible and get new pads and discs.. the disks these days don't put up a massive battle and I've had to replace some at work on Van's at 100k.. motor factor pads can be very hard and eat into the discs. Hence main dealer much better.. softer pads designed for the disc that they will supply for specific vehicle..

OldMrBrennan83

Yeah I'll look up the manufacturer that dealer uses and get a set. Cheers.

rex-x

Turbohymac wrote: »

Theres a lot of wear on that disc by looking at the sharp edge on the outer side.. discs need more attention than pads..sometimes just throwing in pads don't fix the very worn glazed discs.. go to main dealer if possible and get new pads and discs.. the disks these days don't put up a massive battle and I've had to replace some at work on Van's at 100k.. motor factor pads can be very hard and eat into the discs. Hence main dealer much better.. softer pads designed for the disc that they will supply for specific vehicle..

To be fair there aren't many cars or vans that will get more than one set of pads to a set of discs, two sets of pads at the very max if not too rusted out
Doesn't stop people just slapping pads on though like in this case

listermint

rex-x wrote: »

To be fair there aren't many cars or vans that will get more than one set of pads to a set of discs, two sets of pads at the very max if not too rusted out
Doesn't stop people just slapping pads on though like in this case

To be fair that's bollix.

rex-x

listermint wrote: »

To be fair that's bollix.

In what way? I change maybe 20 sets a week and very few cars are still in spec after 1 set of pads let alone 2 sets. BMW 5 Series, A4 etc you have no hope of 2 sets of pads. Smaller cars like a clio you might get 2 sets but by the end of the second the discs will be f*cked.

The limits for disc wear are tiny < 1mm per side

REXER

rex-x wrote: »

In what way? I change maybe 20 sets a week and very few cars are still in spec after 1 set of pads let alone 2 sets. BMW 5 Series, A4 etc you have no hope of 2 sets of pads. Smaller cars like a clio you might get 2 sets but by the end of the second the discs will be f*cked.

The limits for disc wear are tiny < 1mm per side

Sure they are, thats why the minimum disc thickness is stamped on the edge of the disc! :eek:

smuggler.ie

rex-x wrote: »

The limits for disc wear are tiny < 1mm per side

It would not be quite correct to replace disk only under that condition, it depends...

It is still down to disk spec's per manufacturer, initial thickness and min thickness allowed/required.
Other thing is aftermarket part manufacturer cutting costs or "modifications" for other purposes.


OEM vs Non-OEM Rotors and Pads

rex-x

Absolutely it does depend on the vehicle but the vast majority of 'ordinary' discs are 1mm or less per side.

E.g. I have a set in my hand from a 2013 GT86 coupe right now. 24mm new with 22mm min thickness so exactly 1mm. Rust buildup is almost more of an issue than min thickness though depending if the discs are coated or uncoated

smuggler.ie

As yourself agreed, it depends on car and disk manufacturer.

"Vast majority" is not necessary make and model of OP's car.

However, your car - your liability. Better safe than sorry.

Whocare

What would happen if you ignore the minimum thickness let's face it is unlikely that disc would break but let's say if you're involved in a bad crash ( let's see you knock someone down who ran out in front doors 100% his fault but your car now will be inspected roadworthiness) and the car was inspector what would happened

OldMrBrennan83

Whocare wrote: »

What would happen if you ignore the minimum thickness let's face it is unlikely that disc would break but let's say if you're involved in a bad crash ( let's see you knock someone down who ran out in front doors 100% his fault but your car now will be inspected roadworthiness) and the car was inspector what would happened

I genuinely don't know what would happen, but it does have a valid legitimate in-date NCT certificate if that's what you mean.

rex-x

OldMrBrennan83 wrote: »

I genuinely don't know what would happen, but it does have a valid legitimate in-date NCT certificate if that's what you mean.

I think what he means is it's the owners responsibility to make sure the car is road worthy (nct is only a snapshot in time) and what would happen if the car was inspected after the accident and it was found to be defective (discs too thin)

I'd imagine not a whole lot of trouble really if it's even picked up on but I have seen them come apart when too worn so not really worth ignoring

mullingar

Nearly all the brake discs I have replaced over the years are limited to max 1mm wear per side (or down to 0.8mm/side if its a skinny disc)

I too found heavy cars a lot harder on the discs than lighter cars, so lighter cars should get 2 pads per disc, heavy cars usually exceeds the 1mm/side wear if they last 2 pads.


The NCT is only a snapshot on the day and they only check for brake performance, not any visual or measured wear, but I think they are introducing a visual inspection soon.


DONT use a main dealer for any older car that just needs pads/discs, anyone can do these.

dodzy

rex-x wrote: »

Absolutely it does depend on the vehicle but the vast majority of 'ordinary' discs are 1mm or less per side.

E.g. I have a set in my hand from a 2013 GT86 coupe right now. 24mm new with 22mm min thickness so exactly 1mm. Rust buildup is almost more of an issue than min thickness though depending if the discs are coated or uncoated

I know you know your stuff Rex but manufacturers recommendations are always going to favour more frequent replacement for obvious reasons. 1mm off a disc surface surely would have insignificant impact on braking or safety, assuming pads are good of course.

rex-x

dodzy wrote: »

I know you know your stuff Rex but manufacturers recommendations are always going to favour more frequent replacement for obvious reasons. 1mm off a disc surface surely would have insignificant impact on braking or safety, assuming pads are good of course.

The 1mm thing is pretty universally agreed, it wouldn't be a case of manufacturers trying to screw people IMO.

Most discs are vented so the surface on each side of the vent is only 5-7mm thick in most cases. They also corrode badly from the inside and once worn 1mm you may be actually down to half the original thickness and then this happens:


Took these off a car the owner saw nothing wrong with and didn't want new discs just the noise fixed...... worn only about 1mm - 1.5mm per side





They weaken significantly and lose their heat capacity so 1mm is about right for replacement. There is also the argument that if you throw a new set of pads on at 1mm then what will the discs be like by the time that set are done? Dangerous most likely

The pads also get caught in the lip on the disc even if it is only slight and can stick on, squeal or create uneven contact