Worn brake discs an NCT Fail item?

eggerb

I had some tyres replaced recently by Advance Pitstop and they advised that my brake discs were worn; only the discs not the pads.

The surface looks fine - no corrosion, smooth and shiny. The extreme edges of the discs look slightly frayed - there's probably a better technical term.

Question then, are worn brake discs a potential NCT failure item? I couldn't find any NCT reference but this AA site here makes reference to the [UK} MOT ...

Surface pitting
This used to be a reason for MOT test failure but data available following the introduction of the computerised MOT showed that too many cars were failing the test on 'brake discs pitted' even though this was not sufficient to weaken the disc.

VOSA(Vehicle and Operator Services Agency) has subsequently revised the testers' manual and now discs should only fail the test if they have become 'seriously weakened'.

Source: http://www.theaa.com/motoring_advice/general-advice/brakes-discs-drums-pads.html

mickdw

Look at it this way. They won't fail unless they are gone so thin that they are dangerous. At that point they are doing you a favour.
I wouldnt be taking advice from these franchise tyre places re works needed.
Get a good honest mechanic to check your brakes

Sam Kade

Get them checked at an independent. Advance are great at finding faults to relieve you of your money.

grogi

eggerb wrote: »

I had some tyres replaced recently by Advance Pitstop and they advised that my brake discs were worn; only the discs not the pads.

Changing discs without pads? Better change a mechanic.

Atlantic Dawn

Let the NCT test them and see what comes back.

savagethegoat

over 50% of car fail on the first test, may as well get it tested to see what else it may fail on

CiniO

Google the minimum thicnkess of discs for your car, and then measure them.
You will know if they are worn or not.

pajero12

grogi wrote: »

Changing discs without pads? Better change a mechanic.

I changed a set of pads before and a month later it failed the nct on worn discs? Should i have put another new set of pads in? Hardly

Sam Kade

pajero12 wrote: »

I changed a set of pads before and a month later it failed the nct on worn discs? Should i have put another new set of pads in? Hardly

Yes you should if the discs are worn they could wear pads uneven especially after a month.

eggerb

Thanks everybody. I should clarify here .. they were recommending a change of discs and pads because the discs were 'worn'. They seen the wear as part of a routine "courtesy check". There's a line item on the receipt saying "courtesy check". They might be better to rename it "pre-sales check". By the sounds of it then, if I have plenty of wear on the pads, discs like I am describing are not particularly dangerous. I think I'll take it to the NCT and see if it passes. Cheers.

biko

Get a second opinion.

JohnBoy26

grogi wrote: »

Changing discs without pads? Better change a mechanic.

They told the op that the discs were worn and the pads were not. You're jumping the gun.

Jayop

JohnBoy26 wrote: »

They told the op that the discs were worn and the pads were not. You're jumping the gun.

Exactly. He made no reference to whether the pads would need to be changed, only that they weren't worn.

As for the disks being worn, I'd put it though the test, if they fail it then change them, if not then they're clearly fine.

Better a retest fee of 30 odd quid than a few hundred changing discs that don't need doing.

gctest50

JohnBoy26 wrote: »

They told the op that the discs were worn and the pads were not. You're jumping the gun.

No, he's not, put in new pads if you put in new discs

JohnBoy26

gctest50 wrote: »

No, he's not, put in new pads if you put in new discs

He is. Nowhere is it mentioned that the op was advised not to change the pads at the same time.

It's a bit rich to say get a new mechanic without knowing all the facts.

Jayop

gctest50 wrote: »

No, he's not, put in new pads if you put in new discs

Them saying the pads are not worn doesn't mean they won't change them anyway. Knowing Advance I'd be very very surprised if that was the case.

gctest50

.
-60% Sale on Bosch discs for Audi 1.8T :


280mm

http://www.mister-auto.ie/en/front-brake-discs/bosch-0-986-478-869_g900007_a0300!986!478!869.html

288mm

http://www.mister-auto.ie/en/front-brake-discs/bosch-0-986-478-546_g900007_a0300!986!478!546.html

barneygumble99

Discs (not all discs though) have a metal wear indicator that will break off when it gets below a certain thickness.

CJhaughey

barneygumble99 wrote: »

Discs (not all discs though) have a metal wear indicator that will break off when it gets below a certain thickness.

Where would that be? I haven't seen one on any Japanese car that I ever changed discs on.
There is usually a Min. Th cast into the disc on the ones I have changed.

coylemj

I don't think the wear indicator 'breaks off', I think it consist of a soft metal contact embedded within the pad and when the pad wears down and that contact becomes exposed, it makes an electrical circuit by coming into contact with the disc, that in turn causes the wear indicator to light up on the dash.

Jayop

Isn't the wear indicator normally on the pads and not the discs?

CJhaughey

Thats different to a disc thickness breaky offy bit though.
Pad wear indicators have been around for a while now.
Hard to beat the old squealer though, that noise will get people to look much faster than a little orange light.

greasepalm

do not rely on nct to think your brakes are safe,we have had 4 cars in the last year that got through the nct no faults/comments and weeks later brake pad falls out as disc is dangerously worn.owners need to have their cars serviced and getting a nct cert means nothing for safety.
what does the nct add say now " car is all right at this time "?
discs and pads are a regular thing as pads are harder and wear discs away ,big lip on edge of disc means its worn. black marks on discs could be high spots on discs causing hoppy pedal.

japanese cars use a brass finger on pad and when touching disc and wheel rotates audible scratching warning.
other makers may use a wire for wear embedded into pad and when cut/grounded lights up dash brake light warning.
wires also break on older cars then wont work or not connected with last pads fitted.

coylemj

CJhaughey wrote: »

Hard to beat the old squealer though, that noise will get people to look much faster than a little orange light.

That 'little orange light' system has saved me a shedload of money. On my last three services, my (main dealer) service people have told me my brake pads won't last until the next service. I have >80,000 kms on the clock and the car is still on the original factory pads. I simply tell them that I'll get new ones when the 'little orange light' comes on.

I think the same applies to a lot of other people, they know they can tell the service guy that they don't need new pads which means the current scam by unscrupulous sevice people is to tell people the discs are worn because they know that people are aware of the wear sensor system.

greasepalm

do you know what a brake pedal is for:eek::D some mileage

CiniO

gctest50 wrote: »

.
-60% Sale on Bosch discs for Audi 1.8T :


280mm

http://www.mister-auto.ie/en/front-brake-discs/bosch-0-986-478-869_g900007_a0300!986!478!869.html

288mm

http://www.mister-auto.ie/en/front-brake-discs/bosch-0-986-478-546_g900007_a0300!986!478!546.html

Are Bosch dicsc good?
I see there's offer for most model - also 60% for my honda.

However TRW are only 5er more expensive - wouldn't they be better?

Or ATE another 4 quid more than TRW

CiniO

Jayop wrote: »

As for the disks being worn, I'd put it though the test, if they fail it then change them, if not then they're clearly fine.

They don't check for disc thickness on NCT, so it might be below manufacturers recomended minimum, and still pass NCT.

So fact that car pass NCT, doesn't mean discs are fine.

coylemj

CiniO wrote: »

They don't check for disc thickness on NCT, so it might be below manufacturers recomended minimum, and still pass NCT.

So fact that car pass NCT, doesn't mean discs are fine.

True but the fact that Advance wanted to replace them wouldn't keep me awake at night either.

CiniO

coylemj wrote: »

True but the fact that Advance wanted to replace them wouldn't keep me awake at night either.

Of course. That's why I advised OP to measure them himself.

Jayop

Would dodgy discs not normally show as a bad brake imbalance on test?

CJhaughey

CiniO wrote: »

Are Bosch dicsc good?
I see there's offer for most model - also 60% for my honda.

However TRW are only 5er more expensive - wouldn't they be better?

Or ATE another 4 quid more than TRW

All good brands there, I'd personally go for Brembo when I need a new set.
ATE are OEM for Honda Accords Mk7 so probably Civics as well.

CJhaughey

Jayop wrote: »

Would dodgy discs not normally show as a bad brake imbalance on test?

No, because the pressure on each disc is the same no matter the thickness.
Brake Imbalance is a pressure differential or a possible frictional difference if different pads/discs are used from side to side or contaminated with oil etc

greasepalm

dont forget about the seized brake pad in carrier scenario as having to lever rusted pad out with a big bar,rear brakes in vw as most popular.