Graunchy brake disk

[Bonce]

Yet another brake question I'm afraid.

Under light braking I get an uneven graunchy noise - "grshh-grshh-grshh" and squeel from what appears to be my front left brake disc. I can feel it through the pedal too.
I thought that maybe some abuse on track would fix the problem if it was something on the surface, but it didn't.
The brakes are fine when I stand on them, they stop the car quickly and evenly and neither side locks before the other, but it's very annoying and detracts from general driving, particularly round town.

The discs are original S1 111S cross drilled ones and they've done 27,000 miles, I'm using them with Pagid 4-2s. Do you think it's time for new disks?
What do people recommend? Are cross-drilled discs actually any good?
I could probably get them from Race-speed at PistonFest this Sunday.

Cheers!

[Bonce]

Bugger, forgot to ask my numpty question: do I need do replace the pads if I replace the discs?

[cuzza]

Bonce said:

Bugger, forgot to ask my numpty question: do I need do replace the pads if I replace the discs?

Yes, you must replace the pads with the disks.

The noise you so eloquently describe could be the pad on the back of the disk is more worn than the front so you can't see how bad it is. How long have you had the pads for?

[Bonce]

The pads have done 6000 miles. Don't tell me they're scrap already!?

[cuzza]

If the disks need to be changed then I'm afraid they are.

It may be that the pads have knackered you disks as the Pagids are uprated but the disks are standard (and fairly well used).

I'm sure someone will tell you it's OK to use the old ones but your brakes are your lifeline.

[moomin]

cuzza said:

I'm sure someone will tell you it's OK to use the old ones

yep, me
the pads will be bedded to the shape of the disc surface, but that doesn't mean they are deaded, just that they may need extended bedding in on new discs.

Bonce, I'm not sure about the noise, but I'll have a listen if you like. you should whip the pads out really for an inspection to see if it is anything obvious.

Edited to try to get the quote right.

>> Edited by moomin on Friday 27th June 14:05

[cuzza]

moomin said:

yep, me

LOL

If it's an intermittent noise, it could be that the disc is warped, particularly if you can feel it through the pedal too.

And I stll wouldn't use the old pads!

[dragstar]

whilst on the topic of brake discs, did anyone find out how to stop squealing breaks at low speeds?

my breaks are great (standard drilled) but, like a thread centre'd on a few days ago, squeal like hell.

or did i just miss the solution?

p.s., my dumb question of the day is, how do i know when my discs are scorched? (im sorry, im just not that technical) and does this mean i have to change discs as well as pads?

cheers

[Beefcake]

Should be fine to keep your pads, I did this on my 111s with Pagids. Fitted Gearys belled discs they just took a little longer to bed in than normal but surprisingly quickly to be fair!

Was expecting to have no brakes at all but from day one they were stopping really well even though not all the pad was making contact at that point!

My standard discs were making the "graunching" noise you describe when they were on the way out.


--
www.midlandslotus.co.uk

[DanH]

Squeal can be sorted by putting coppa-slip on the back of the pads (i.e. between pad and caliper NOT pad and disk lol). At least this is what everyone says, I've not uprated the pads yet so not been an issue for me.

[alunr]

DanH said:

Squeal can be sorted by putting coppa-slip on the back of the pads (i.e. between pad and caliper NOT pad and disk lol). At least this is what everyone says, I've not uprated the pads yet so not been an issue for me.

I found just giving mine a good "bedding" in whenever the noise turned up sorted it out fine.

[fergusd]

You should whip the wheel off and check the inner pad surfaces, sometimes they can wear faster then the outers (much from the road can increase the wear rate) . . .


If the pads are shot (not impossible) then new disks and pads.

Next thing I'd inspect is the disk surface for damage/cracks, this could be the noise . . .

If everything looks OK (get someone who knows what to look for if you're not sure) then I'd just run the pads to the end of their life and replace everything at once . . .

Many people are using EBC Turbogroove disks, they are not fully crossdrilled so are not as susceptable to cracking . . .

Eveything you need at www.lotusecosse.com

Fd

[Bonce]

Cheers, guys. I'll get them inspected by an expert.

Annoyingly I took moomin for a drive this morning to demonstrate and let him drive to feel the vibration but sod's law came into play and they were absolutely fine. Gah!

I need to take moomin with me whenever I go for a drive now in order to keep the brakes healthy.