A Juddering on brakes on new discs!

Hi,
I recently upgraded my brake discs on my car, but I notice theres a slight judder when I apply the brakes.
All the discs are upgraded to 40 grooved and rear pads too.
The front pads had plenty of life left on them, so my mechanic left them on.
Dont you think the juddering is casued by the old front pads?
Or shall I change the front brake pads?
I know that the brake discs can be fitted either way!
Any info will be appreciated

You sure the discs are mounted the correct way round? You need to leave time for the old pads to bed in properly. Really only the discs cause judder unless your calipers are not applying equal pressure.

Grooved disks do make a sort of buzzing when new but not a judder.
I can't believe they fitted new disks with old pads for one, I'd do them both together but did he clean off the hub face to make sure the new disk is sat flush on it ?

Its not totally impossible for the disc to be defective - I once had a brand new set of discs that juddered REALLY badly - turned out they had been badly machined and the disc thickness varied by about 0.25mm

However, this is extremely rare, so I would suggest the discs are probably not seated against the hub properly (it only takes a tiny speck of material to cause quite a large deflection at the edge of the disc)

I suggest taking the discs off, cleaning the hub and disc faces with a wire brush, then feeling the faces for any other imperfections - then re-fit

Hi
I took some photos of the front & rear wheel.
The brakes are fitted the wrong direction but sometimes is not an issue on some groove brakes.
As my mechanic said, he fitted it that way because of the cooling cycle on groove discs.
Now we are going to switch around the dics and put a set of new front pads on, hopefully that will cure the problem.
The juddering only happens above 60mph.

http://i59.photobucket.com/albums/g281/tarosanuk/frontbrakes.jpg

http://i59.photobucket.com/albums/g281/tarosanuk/rearbrakes.jpg

"he fitted it that way because of the cooling cycle on groove discs."

Your mechanic is trying to justify a mistake; they are the wrong way round, no arguments. As long as he is not trying to charge you extra to fix the problem all is good. At least you have found the cause now. Can’t mess about when it comes to brakes.

Having the grooves that way doesn't affect cooling at all but i will tell you that the direction of the grooves has nothing to do with the judder. I have mine in the supposed wrong way and have not experienced any problems.

Well weather it fixes the issue or not it is a problem found and fixing it can only be a step in the "Wright direction" . Vturbo let us know how it goes, I hated my brake judder it was very dangerous. Follow this guide

The direction of the grooves only apply if the veins have directions/curve. In most cases, they are standard discs (straight veins) with grooves cut into them. From the picture vturbo posted, it looks like discs from CRN?

A bit of a sweeping statment with no justification there !

The pagid disks are meant to be fitted that way round as instructed by the stickers on them.
What brand of disk are they ?

They didn't knock a wheel balance weight off the wheel whilst fitting the disks did they ?

Pagid makes discs?

The disks are not Pagid & no stickers to indicate direction.
There are unbranded ones.
I got the car booked in on Friday morning, we are going to swap the disk round and fit new front Mintex pads on, matching the rear.
Fingers crossed

Hope it works dude.

Pagid sure do make disks, nice ones too, grooved similar to tarox but don't rust like tarox.
Works well with pagid blue pads.

Are you sure Pagid don't just stamp their name on another brand of discs as i can't find any offical info on their own discs?

vturbo you say this only happens over 60mph are you talking balance our braking at 60

After 3 seconds of google searching I found http://www.motorsportworld.co.uk/frame-detail.asp?PAGE=/pagid-pads-discs.htm

I saw that too but it's not from the manfacture but a reseller. Why are they not listed on Pagids website?

Ok found them, its on the German site not the UK one. They are owned by TMD friction who also own Mintex etc

I had a set of Pagid discs on my first Coupe - VERY good quality, VERY expensive.

They lasted about 1000 miles - not the discs fault - I crashed the car

sorry Nigel, I shouldn't have laughed at that but I did!

Same actually...

Read the first bit and thought he must of missed a few 00's

my G3 discs are going the same way theyre noisey when i brake too, humming it starts at 40mph, are mine on the wrong way too?

I couldn't get on with grooved discs personally because of the noise - I now have plain discs which are fine with uprated pads.

The more grooves they have the more noisey they seem, groove shape also makes a difference, the G3 style with lots of straight grooves seem to give a real hum.

Just to let everyone know theres no more brake judder, it seems it was the brakes fitted the wrong way & new front brake pads.
My mechanic should of changed it in the first place, but he was trying to save me money.
Thanks for everyones tips!