High Speed Shudder

[Wilko16]

Could have even just lost a balance weight... Those sort of speeds will reveal even a slight out of balance

[Kimberley Scott]

[NZBen]

Took it down a private rd over the weekend at 200 with cold brakes, no shudder. Then again with hot brakes and heavy shudder. I guess that means rotors?

[Wilko16]

If it shudders without pressing the brakes when they are hot

Your wheels have been incorrectly torqued at some stage and warped the discs

Or if your discs have been changed/taken off recently

Could be rust between them and the hub

Either way you need new rotors

Edited 15/04/15 09:36 AM by Wilko16

[masda74]

What rotors and pads do you have?

[PhilMeUp]

Cheap and easy stuff to do:

Clean off any corrosion on the bearing hubs and the insides of the disc rotors. I use a cordless drill and wire brush from a hardware shop. Your vibration at high speed is more of a driveline issue, but this stuff is worth doing anyway.









Tightening wheel nuts: I’m nerdy so use a torque wrench to ensure the correct tightness and consistency. The discs get sandwiched between the wheels and the bearing hubs. One Ford service manual says 125Nm and another one says 135Nm. No big difference - I go with with 125Nm.

I also do this with minimal weight on the wheels - I’ll use a trolley jack to raise the car but have just enough contact between the tyre and the ground to prevent the wheel from turning when I tighten the wheel nuts.





Spending money:

If you don’t know when the tail shaft centre bearing was last replaced then you might as well go replace it anyway. I get mine from Hardy Spicer (www.hardyspicer.com.au) - not sure if they are also in NZ. The normal Falcons use a 30mm bearing, and the turbos and 8s use a 35mm. Easy enough to do on a ute (CV joint) but a bit more complex on a sedan (universal joint, which will probably also need replacing).

If you’re going to be doing high speed stuff regularly then it might be worth considering getting the tail shaft balanced after replacing the bearing.

Photos of changing centre bearing on a ute: http://www.fordxr6turbo.com/forum/topic/89684-2006-fpv-tornado-f6-ute-cleanup-resurrection/page-2#entry1521879

Other stuff to check or replace: Engine mounts and transmission mount.

I know my diff bush is stuffed.

Not fun to replace, but it needs to be done.

Edited 15/04/15 12:14 PM by PhilMeUp