Brake Disc (Rotor) Problem?

Blondie919

I don't know if this is a problem or not, so I don't know if I should be alarmed or what. Thing is, when I saw my rear brake disc last weekend I was alarmed. It's difficult to put it into words. My disc had a solid surface but now there are pre-drilled holes starting to show through. I've looked online and learned that the disc is also called a rotor and that most OEM rotors are solid.

But then why are there holes showing where there were none before? Should I be worried and do I need a new disc?

Kevin McCloud

That disc is overdue a replacement.

Blondie919

Here's another photo.

Korat

That must be a really old bike or you're very heavy on the rear braking.

You need to replace the disc. You might want to check your brake pad alignment too.

Kevin McCloud

Possibility down to metal on the pads by the look of the disc. New disc and pads and check caliper.

Wossack

you always had holes, its just they're full of brake dust Ive seen worse tbh, hows the thickness?

on bikes, most OEM rotors are drilled, more so for aesthetic reasons - they're more visible then on cars (which generally arent)

arybvtcw0eolkf

Wossack wrote: »

you always had holes, its just they're full of brake dust Ive seen worse tbh, hows the thickness?

on bikes, most OEM rotors are drilled, more so for aesthetic reasons - they're more visible then on cars (which generally arent)

^^^ This is most likely OP but since you obviously don't know a lot about your braking system, and you're asking for an opinion from strangers on the internet my advice would be to have a reputable mechanic look at your bike.

disclaimer; nothing wrong with seeking the advice of 'net strangers either but it can't replace the solid advice you'd get from a reputable mechanic.

Blondie919

Jaxson Faithful Socialism wrote: »

^^^ This is most likely OP but since you obviously don't know a lot about your braking system, and you're asking for an opinion from strangers on the internet my advice would be to have a reputable mechanic look at your bike.

disclaimer; nothing wrong with seeking the advice of 'net strangers either but it can't replace the solid advice you'd get from a reputable mechanic.

I had a feeling I needed a new disc but I only asked on here for some knowledgeable advice, a second opinion. I admit I don't know a lot about braking system but there is a lot I don't fully understand about the workings of my bike but there is a lot that I do know.

I called to my mechanic tue morning but he wasn't there. I figured I'd ask here till I speak to him.

I suppose I used to brake hard in the earlier years of owning this bike. Don't think it makes me a bad driver. If anything I learned not to brake so much.

Thanks for the replies, all second opinions. I don't just take strangers on the internet word, I go with my feeling also.

zubair

Am I missing something here?

Wonda-Boy

zubair wrote: »

Am I missing something here?

Depends how much you read Jamie, lol.

The op brake discs are in a bad way, the normal holes on the bad are covered in crust and grime from many factors. He thought that his discs where on the way out because he could see the holes ( that are meant to be clear and clean)

Hotblack Desiato

Korat wrote: »

That must be a really old bike or you're very heavy on the rear braking.

Or the rear caliper is seized partially on, which happens a lot unless the pistons are cleaned regularly.

Judging by the difference in thickness between the swept and unswept area of the disc, there's no way it can still be in spec, needs replacement.

BTW the holes aren't there to look nice, they're there to lighten the disc and help shed water/dirt off the pads.

zubair

Wonda-Boy wrote: »

Depends how much you read Jamie, lol.

The op brake discs are in a bad way, the normal holes on the bad are covered in crust and grime from many factors. He thought that his discs where on the way out because he could see the holes ( that are meant to be clear and clean)

Cheers. I can see the brakes are a bit knackered but is the OP questioning the fact that there's holes? :eek:

Skill Magill

zubair wrote: »

Cheers. I can see the brakes are a bit knackered but is the OP questioning the fact that there's holes? :eek:

If you look at the pictures some holes are filled in and some aren't, think that's what the op is on about.

Blondie919

zubair wrote: »

Cheers. I can see the brakes are a bit knackered but is the OP questioning the fact that there's holes? :eek:

I know that discs have holes in them, my front ones do. I know what the holes are for. All I'm saying is that the disc I had on the rear wheel had a solid surface for the 8 years I have the bike. Yes, it's pretty worn but I just wanted to know why the holes are showing through when it's supposed to be a solid surface. Am I missing something about solids? Are they really just normal discs with a solid surface over them? If the holes are present what's the point of covering them?

Here's a photo of a disc with the same solid surface as my own.

Pardon me for not knowing that when a solid disc wears down that it will show holes. It's another new aspect of motorbikes I've learned. Wish I had just asked my mechanic instead of here.

Blondie919

Wonda-Boy wrote: »

Depends how much you read Jamie, lol.

The op brake discs are in a bad way, the normal holes on the bad are covered in crust and grime from many factors. He thought that his discs where on the way out because he could see the holes ( that are meant to be clear and clean)

The "normal holes" weren't even there up to a few weeks ago! It was a fecking solid goddam surface! Why is this so hard to explain? There's grime and crust in them coz they are beginning to appear.

Blondie919

Skill Magill wrote: »

If you look at the pictures some holes are filled in and some aren't, think that's what the op is on about.

Kind of, yeah. The holes were not there up to a few weeks ago. Now they are starting to appear. Some have crap in them while others are shedding said crap. I just wanted to know why they are appearing on an otherwise solid brake disc.

Wossack

you must be wrong (or winding us up) - theres no way the disc was only drilled 98% of the way through (from the back), so it appeared solid. And now the wearing of the pads is revealing the holes

whats the bike?

CJhaughey

Blondie919 wrote: »

The "normal holes" weren't even there up to a few weeks ago! It was a fecking solid goddam surface! Why is this so hard to explain? There's grime and crust in them coz they are beginning to appear.

You aren't making sense Blondie, the disc clearly shows the holes are there all along, the unswept part of the disc inside the swept area show that there are holes that are rusty and untouched by wear.
Showing a pic of a car disc that is undrilled is like showing a picture of a watermelon.
It bears no resemblance to a motorcycle disc.
Your rear disc always had holes in it from new. You either didn't spot them or ignored them.
There is no way that a motorcycle rear disc has hollow voids in it.

Alkers

What bike is it?

Mr Sheen!

Wossack wrote: »

you must be wrong (or winding us up) - theres no way the disc was only drilled 98% of the way through (from the back), so it appeared solid. And now the wearing of the pads is revealing the holes

whats the bike?

No it was drilled from the centre of the disc out to each side!! So it appeared solid on both sides!! LOL

Mr Sheen!

Bad news lads. After reading this thread last night I inspected my own disc. . . And yup you guessed it there is holes starting to appear in mine now too!!!

Dunno if it's the weather or maybe o parked beside blondie and contracted it??

professore

One of the previous owners probably decided to clean their back brake disk with car wax or something and it stuck there for years in the holes.

Mr Sheen!

@ Blondie This should clear things up a bit for you.

http://www.quora.com/Why-are-there-holes-in-the-disc-of-my-bikes-brakes

zubair

Blondie919 wrote: »

Pardon me for not knowing that when a solid disc wears down that it will show holes. It's another new aspect of motorbikes I've learned. Wish I had just asked my mechanic instead of here.

It was an odd question Blondie and I don't think many of us have seen this before. You should have holes in your disc, it's either crud or they weren't drilled right through in the first place, I can't tell by the picture. Get some brake cleaner and see if that helps, probably need a new rotor though.

dunner515

Hi OP, here's a picture of my rear disc on what it should look like

Blondie919

I'm not winding ye up and I'm not crazy, and not some gombeen who never noticed holes in 8 years. I apologise for putting photo of car disc, got photo from eBay. It looked similar to mine. I will look through all photos I have of my bike to try find one which shows my disc. Will have to wait till tomorrow as in work now

My mechanic is a member of an irish mcc. Surely he would have noticed it all the times he worked on my bike. Bike is a GSF 650.

Tigger

Gsf. 650 rear rotors have holes
http://m.ebay.co.uk/itm/221693382340?_mwBanner=1

Bikes haven't had discs without holes since ages ago

Blondie919

zubair wrote: »

It was an odd question Blondie and I don't think many of us have seen this before. You should have holes in your disc, it's either crud or they weren't drilled right through in the first place, I can't tell by the picture. Get some brake cleaner and see if that helps, probably need a new rotor though.

I agree it's a strange question. I got pissed off with insinuations that I haven't a clue about my bike or that I'm blind or an idiot. I apologise for that.

I have cleaned my disc countless times and never noticed holes. I get up close and personal and I'm not blind or ignoring them.

Wonda-Boy

Blondie919 wrote: »

I agree it's a strange question. I got pissed off with insinuations that I haven't a clue about my bike or that I'm blind or an idiot. I apologise for that.

I have cleaned my disc countless times and never noticed holes. I get up close and personal and I'm not blind or ignoring them.

Nobody said you were clueless or an idiot, it wasn't exactly clear what the problem was so a few of us explained it. There are loads of lads on here who know bikes inside out and will deffo give good advice and steer you in the right direction. No need to throw your dummy out of the pram.... Its all good.

CJhaughey

Blondie919 wrote: »

I agree it's a strange question. I got pissed off with insinuations that I haven't a clue about my bike or that I'm blind or an idiot. I apologise for that.

I have cleaned my disc countless times and never noticed holes. I get up close and personal and I'm not blind or ignoring them.

Have a look at your photo and the one that I have edited showing the holes that are half swept.
They didn't appear in the last year, they were there all along.
One side rusty and one side clean of the same hole and it goes right the way through.

Blondie919

Okay, here goes...............it appears that I AM actually crazy, blind and a gombeen I have a head full of embarrassment.

Yes, my disc always had holes in them. What clogged them up was dust and the material from the pads. It built up as the weeks and months went by. I haven't had the time to give the bike a proper wash and clean since last summer due to starting a night shift job and crappy weather on my days off. I didn't notice them getting filled in I feel like an idiot.

The times when I did clean the disc I do have to admit that the holes really were not visible at all. I can't say why I thought it had a solid surface, maybe it's early onset of dementia or something.

Anyway, went to my mechanic yesterday. The good news is that I don't need a new disc but I did get new pads. He was great about it all, told me not to admit I was crazy. But I'm just a stranger on the internet admitting to other strangers that I am crazy or blind or both.

Got up early this morning on my first full 24 hours off work. I know the day is going to be a cracker, compared to the previous weeks and months. The Bandit is getting parked centre stage out the back, and it will get hours of attention. It will get the best wash & clean it's gotten in a long time. The brake disc will be clear as a mirror (with holes in it) by the time I'm finished.