Brake shudder issue

**mooshie** · 26-08-2013 08:55 PM

I have type R calipers and Fastbrakes.com rotors on my DA9 turbo and am getting shudder issues when light braking. It's worse when going down hill but under heavy braking its fine with no noticeable shudder. I had the rotors machined and the problem went away for about 2000km but is now slowly coming back again.

I am trying to figure out why it's coming back- could they be simply shit rotors and prone to warping? Don't know if this would be the case as I believe Fastbrakes use Brembo blanks.
I have replaced all front end bushings and have a traction bar but the steering rack and tie rods are original and have a slight bit of play on both sides, could this be causing it?
Master cylinder and booster are type R and work well but I have a very slight leak in the prop valve, could this cause an issue? (I know I should replace this anyway)

I am puzzled as to why his is coming back so gradually, I go for some spirited runs in the hills which do involve some heavy and repeated braking but the car cools down well and truly before I park it or come to a full stop. Followed a repeated 80km to 20km/hr break in on them when new and after the machining and I made sure the hubs were very clean before mounting the rotors.

**trism** · 27-08-2013 10:47 AM

warped/hotspotted rotors for sure.

**cbauto** · 28-08-2013 08:19 AM

You must spread butter around before giving to trism again.

**mooshie** · 28-08-2013 09:08 PM

So shit rotors then? Given that I push the DA5 just as hard on the same roads (if not harder) and have not had an issue with standard 262mm front brakes, I am finding it odd that these bigger brakes aren't coping with the heat.

**DreadAngel** · 28-08-2013 09:25 PM

I would also say shit rotors...

What pads are you using? Need to match the pads and rotors

**ChaosMaster** · 28-08-2013 09:40 PM

Rotor warp usually happens when you track the car, and the brakes heat up a lot, yet you don't let them cool down enough before stopping and keeping pressure on one spot. It would be the way you treat your brakes I suspect? That or your pads are agressive and thus eat into your rotors a bit. Normally, what I would recommend would be to do some hard braking, as the pads will machine the rotors back into balance, or at least they should. I would say try that first.

**stocky** · 28-08-2013 10:43 PM

I have no idea what fastbrakes.com rotors are but check the hub bore on the rotor vs. the DA hub. If you have type r rotors on the DA hub without a centering ring, your rotors wont sit right exhibiting those symptoms

**mooshie** · 29-08-2013 10:25 PM

Interesting point regarding the DA hub stocky, I have never heard that before and can't say I checked when I put them on there. Will have to check it at next opportunity. I do look after the brakes and as said, only having an issue on this car, not the other one which gets driven just as hard although less power, never had this issue previously on the OEM DA brakes before I upgraded either.
I am pretty sure the pads are Hawk HP(S?) if that helps but can't remember exactly.