Brake disc grooves

[S73W4R7]

Hi all,

My misses has a Citroen C3, the cars 5 years old now, MOT guy pointed out the brakes were shot last year so I looked into new ones.
Got a full set front/rear of Brembo's from Euro's for around £250.......thought they were a cheap deal.
So they've been on a year now, not done a huge amount of mileage either, but I've noticed some grooves in the discs.
Guessing the pads have caused this, but should I get the discs re turned or replace them, or is it a case of just changing pads will be ok?
Have to say I'm a little disappointed in their condition already.

Edited by S73W4R7 on Sunday 3rd April 09:14

Edited by S73W4R7 on Sunday 3rd April 09:15

Edited by S73W4R7 on Sunday 3rd April 16:34

[dontlookdown]

Take it out for a run, warm the brakes up and then give them some stick. May clean up after 20 miles of hard fast stops.

If not then they prob do need skimming.

Does a C3 have drilled discs as standard? Just curious, seems a bit OTT for the type of car.

[GreenV8S]

Don't use drilled discs.

If your brakes are getting hot enough to need the extra degassing, they're also hot enough for fatigue cracking to be an issue. If they aren't getting hot enough, all the holes are doing is giving you reduced pad contact area, more noise, more dust and brake wear, and potentially uneven brake wear as you're seeing here.

If you're in motorsport and need the extra degassing, use grooved discs rather than drilled.

Edited by GreenV8S on Sunday 3rd April 18:43

[stevieturbo]

Presumably it gets infrequent and easy use.

They're hardly much worth worrying about. As others say, a good hard blast may clean them up.

[georgeyboy12345]

This is why you should replace the pads at the same time as the discs. It’s a false economy not to

[Smint]

Zooming in those discs don't look especially worn.
I'd be inclined to give the brakes a good full service before anything else.
If there's life yet in the pads i'd carry on driving with them and then replace the lot when the time comes.

Agree completely about drilled discs, never found them, or grooved, necessary with properly maintained brakes using decent quality materials.

[Chris32345]

georgeyboy12345 said:

This is why you should replace the pads at the same time as the discs. It’s a false economy not to

full set front/rear of Brembo's




Rather sounds like they did



All though £250 sounds rather expensive for a Citroen c3 discs and pads certainly not cheap price

[Driver101]

How many miles? There is a significant lip to say a lot of miles or hard braking.

The dark lines don't look like grooves to me. It's just the drilled holes causing issues with the pad dust.

[S73W4R7]

Thanks for the replies,
I put the drilled discs on because my thoughts on drilled are they are better in wet condition, at least that what I thought!
She definitely doesnt get the brakes hot so maybe I either need to blast them on the odd occasion, or change them for non drilled?
I never gave a thought to the gasing issue

Edited by S73W4R7 on Sunday 3rd April 16:32

[GreenV8S]

S73W4R7 said:

my thoughts on drilled are they are better in wet condition, at least that what I thought!

They are not better in wet conditions. For almost all road cars they're just a fashion statement.

[Pica-Pica]

I have the same issue on my 335d (large discs, but not drilled). I put it down to limited use, low braking (I tend to anticipate and roll up to slower traffic, plus salted roads (with the car sat there after gritting). BMW wanted to change all pads and discs at a brake fluid change and before its MOT. I just said, change the fluid, forget the MOT. Took the MOT elsewhere, passed on brake performance but had advisories on the discs. I have tried a few hard stops (60 down to 20, never a full stop), slight improvement. I shall probably see how they go before the next MOT. Note: it’s the offside ones that are worst affected for me, sitting in the gritters path no doubt.

[E-bmw]

So, you say you have had new brakes fitted.

Is that disc, pads, calipers or what?

You say it is a Citroen c3 and yet you seem to have bought track day discs, why?

The wear pattern is typical for drilled discs that are barely worn, with blocked holes & under-used & guess what? That is what you have.

[S73W4R7]

They're not track day discs, if you read early comments you'd know I said drilled discs work better in wet conditions, or so I thought.
If one wants track day discs then one fits grooved discs.
Not sure why your so agitated with me fitting drilled discs to my misses motor simply because I felt they'd be better in wet conditions.

[stevieturbo]

Drilled discs are pretty much completely pointless on a mundane road car. And if anything, a downgrade, as they will crack sooner

But it's no big deal, either drive away at it, or just replace them with normal discs.

[E-bmw]

S73W4R7 said:

They're not track day discs, if you read early comments you'd know I said drilled discs work better in wet conditions, or so I thought.
If one wants track day discs then one fits grooved discs.
Not sure why your so agitated with me fitting drilled discs to my misses motor simply because I felt they'd be better in wet conditions.

They don't work better in the wet, which is why no mainstream car manufacturer fits them to cars that get driven in the rain, not sure where you heard that.

Most TD drivers will fit drilled or grooved, they are both theoretically for the same reason, gas dissipation.

I am not agitated with anyone, sorry if you think that, I am just trying to help, which takes me back to the original question which you still haven't answered.

You say you fitted new brakes, but not actually what is new, discs, pads, calipers all of the above, what is actually new?

[S73W4R7]

I fitted discs and pads front/rear, the reason I went for drilled as mentioned was simply as I felt safety was the view to take.
I've since learnt there's obviously more to it than that, and in hindsight, I should of gone for normal 'quality' disc and pads instead.
That being said, I've taken her car out this morning and given the brakes a heating up, as smooth and consistently as I could and already there is an improvement.
It's funny, but the Brembo site. says drilled are better in wet conditions, so I don't know where my thoughts on that lay.
👇

https://www.brembo.com/en/company/news/disc-drille...

[steveo3002]

looks like lack of use , once they get past a certain amount of rust theyre hard to get clean again with normal braking

inside of the disc is often much worse so take a look at that before making any decisions

[Panamax]

Yup, I'll bet that photo is a rear disc.

Rear brakes on a small hatchback are almost completely superfluous and do very little work. This is part of the reason some small cars went on using rear drums long after disc brakes became mainstream. Then the combination of (a) appearance, and (b) ABS systems led to discs all round being the norm.

It's very difficult to clean up discs that have started to corrode because the corrosion chews away that part of the brake pad.

Unless and until they become a problem at MOT it's probably just a case of living with it. And get ready to fit some standard discs/pads next time. They're not usually too expensive these days.

[Maxdecel]

S73W4R7 said:

It's funny, but the Brembo site. says drilled are better in wet conditions, so I don't know where my thoughts on that lay.
?? https://www.brembo.com/en/company/news/disc-drille...

Are they more expensive than plain bog standard by any chance ? Marketing departments have a way with words.

[QBee]

I was advised (warned) to use grooved disks for track days, not drilled, because under track day usage (seriously hot brakes, lots of hard stops} drilled disks can crack from the drilled holes.
I cannot see your Mrs emulating my track day driving in her C3 on normal road use ( I assume she doesn't brake hard from 100+ mph, 5 times every 2.7 miles), so I think these disks will be fine and, as advised above, may well clean up with a bit of a thrashing on a few local roads. How do the brakes feel?

I always fit plain disks to my road cars with good quality pads, but all credit to you for trying to do the best for your beloved's car. The thing not to do is fit the cheapest pads you can find, which you have not done.
Proper track pads can be awful in road use, as they tend to need to be hot to work properly. I had a set which were great on track, but arrive at the end of our road a bit briskly after 800 yards from cold and I could easily end up in the hedge opposite the junction. I fit fast road/track compromise pads (referred to by Hawk as "street/race") to my track/fun road car for this reason.