Noisy brake discs

[PranK]

Hey all,

My Bora is wearing RDA slotted front discs and Remsa pads (as are many others, thanks to GSL) but lately they have become pretty noisy.

I do get a bit of surface rust on them, I dont mind that but the noise makes me uncomfortable. I dont feel anything through the pedal or steering wheel, so I'm not *too* concerned. Unfortunately my car is only used (generally) for the 15m commute to work and back daily and the noise is there for pretty much the entire drive.

Its an *almost* grinding noise - not a proper grinding noise, but a hard rubbing that is *almost* grinding. I go down Mona Vale road (if you know it) which ends with a big hill and going down there is the worst.

Anyway, could just be normal, I know it is normal for the stocker rotors to be noisy, but not sure about the RDA's (I know they are not as good as DBA's but should still be better than stock.)

Thanks guys.

[Bflat]

I've been getting this the last week or so as well, I've got Greenstuff pads on ventilated and slotted discs (brand escapes me at the moment) and the noise matches exactly with your description.

I also don't know what the reason is and would welcome anyone to chime in with possibilities.

[Back Door Shenanigans.]

I'd say its just most likely dust or crap on the pads/disks. My brembo's started doing it after the track day so that would be due to glasing them over (which can happen down hills if you ride the brake). I'd try bedding in your brakes or a couple of really hard stops to clean the pad and rotor. Failing that im fairly sure you can buy anti squeal stuff.

Edit: have to ask, You checked your brake pads made sure they have meat?

[PranK]

I'd say its just most likely dust or crap on the pads/disks. My brembo's started doing it after the track day so that would be due to glasing them over (which can happen down hills if you ride the brake). I'd try bedding in your brakes or a couple of really hard stops to clean the pad and rotor. Failing that im fairly sure you can buy anti squeal stuff.

Edit: have to ask, You checked your brake pads made sure they have meat?

I havent checked them, but the pads and rotors only went on maybe 2000 k's ago. I can't do any brake mashing atm because my ABS is engaging early. Ergh, brakes suck... Wish we didnt need them.

[balkanac]

you should be able to pull the ABS fuse (which will turn off the AWD system too) and try breaking hard a few times.
Ift hat doesnt help you'll have to take the calipers off and put a lot of anti squeal paste on the pads

[PranK]

Yeah good idea.

Thanks.

BTW, thought you guys might like this ...



Heh , apparently I have a noisy bra!

[JustCruisn]

Did you replace the brakes your self ? Did you use anti squeal on the back of the pad? Is the rotor flush to the hub, sometimes you need to remove rust with a wire brush. Check the rotor retaining bolt is tight too.
Removing pads and roughing them with sand paper or concrete can remove glazing. Is there a build up of pad material on the rotor, maybe on the back side so hard to see.
Your abs issue may be caused by a loose sensor at the back of the hub.

[PranK]

Did you replace the brakes your self ? Did you use anti squeal on the back of the pad? Is the rotor flush to the hub, sometimes you need to remove rust with a wire brush. Check the rotor retaining bolt is tight too.
Removing pads and roughing them with sand paper or concrete can remove glazing. Is there a build up of pad material on the rotor, maybe on the back side so hard to see.
Your abs issue may be caused by a loose sensor at the back of the hub.

I did do the brakes myself, yep. The front wheels have been off a fair few times lately, and I did notice the retaining bolt was loose on one of them last time. I'm scared to use loctite or something on that bolt as its only a philips head and could be a bastard to get out.

ABS issue is *probably* due to either the G200 lateral sensor which has been throwing intermittent errors, but could also be caused by a loose abs sensor as I had to get a broken wire on the front passenger side fixed recently.

How would the glazing occur? Lack of driving? Its not driven on weekends, but it is every other day, even if just for a 25k round trip.

So, looks like this weekend, I'll take both front wheels off, ensure the rotors are flush and retaining bolt is super tight, I'll remove any excess rust and might even apply some anti squeal.

Thanks for the help!

[JustCruisn]

Dont use loctite. I had a funny noise and found the bolt missing. A new one was only 48 cents and is a torx not phillips. The rotor can move a bit without the bolt. If not seated correctly you can get vibrations and other noises.

[golfgti101]

glazing can be, like ssaid above, from riding the brakes down that hill you mention.. best thing i'd suggest is fix the ABS up before it could give a dangerous change.. then give the brakes a new bedding in.
a couple of hard stops from 60km to 10 should give you some new meat.

goodluck!

[Back Door Shenanigans.]

Dont use loctite. I had a funny noise and found the bolt missing. A new one was only 48 cents and is a torx not phillips. The rotor can move a bit without the bolt. If not seated correctly you can get vibrations and other noises.

Ah those bolts are only to locate them on there when the wheels are off. Once the wheels are on the wheel bolts will actually hold the rotor in the right place and that bolt wont do anything. So as long as you tighten your wheel bolts in the correct pattern and tight enough it should sit flat and the disks shouldn't be able to move at all. one of mine had a missing screw (which by the way the new ones come with torx heads if your worried) and i never noticed any problems with it.

[PranK]

Well, can confirm the rotors were nice and flush against the hub, no carrier movement, no glazing.

A bit weird, im going to take it to European Autotech this week and see if theyll be able to diagnose it.

Thanks guys.

[kendog]

Where does one buy this 'anti squeal stuff'?

My 1.6L front brakes seemed to suffer from it, but the GTI seemed fine when I test drove it the other day.

[JustCruisn]

Your fav auto parts store will stock it. It goes on like glue, on the parts that contact the calliper. It creates a vibration adsorbent barrier.

[kendog]

Cool, thanks!