[FLOORED]

Originally Posted by MattSAU2XR8

Hey guys,

This is probably my final installment on the topic of FG brake shudder

I've been having trouble on and off for a few years as follows:
- Bought a near new FG Ecoboost G6E in 2013, thought the brakes were a bit weak, and upgraded to RSA slotted fronts and Ferodo DS performance pads all round. Certainly stopped well but started shuddering almost immediately, and I could feed the pedal moving up and down a little as soon as they were installed.
- I had noted when putting the RDA's on that according to my dial gauge they were up to 7/100 mm out, i.e. surfaces not flat as they rotated, and so shuddered badly from 80 kms up
- After a while got some PBR slotted discs to swap the fronts out thinking that if Ford use them they should be good, i.e. minimal runout, at least initially. However not the case, as I recall at least 4/100 mm out and I think one may have been 6/100.
- Not wanting to buy more discs, and figuring I could gradually fix two problems which were (a) pad deposits, and (b) runout, I installed some Bendix Ultimates which are known to be a bit abrasive. 25,000 kms no shudder and the brakes are great!
- Given I'm selling the car now (have bought a VE SS - sorry guys) I finally installed some DBA 4000 plain rotors I'd bought on sale a while back. The result from the dial gauge - 1/100 mm runout on each of them as soon as I fitted them up, so good I didn't even bother indexing them!

So for me there are two morals to this story:
- Brake discs often do have runout when new, and this can cause shudder, regardless of what brake manufacturers say
- Top quality discs, i.e. DBA 4000s are less likely to have shudder

I can only imagine Ford used to machine all the PBR discs on the car as it was being assembled....

I'm wondering now how the DBA street series might go in future on the SS - seems that most of the problems I;ve been having are not related to overheating the brakes, just due to them having runout when new. The metal itself is probably good enough since they seem to improved with age...

DBA also have a very expensive dial gauge in a room that is temp controlled. They do various runout checks on there disc rotors whilst in production as to not have this issue.