Brake or Suspension Shudder

[sshh]

VT Commodore Wagon, I have a shudder through the steering wheel when coasting down hill at about 60-80km and braking slightly.

I know the front discs on these are known for warping but I can't get the car to replicate the problem any other way other than that mentioned above no matter how light or heavy I brake or at different speeds.

So is it still likely to be the front discs or could it be a weak link in the suspension somewhere? I only think suspension due to the weight shift when I am rolling downhill.

All the bushes appear to be in reasonable condition, definately not still factory looks like pedders have giving it a once over in the last few years sometime.

Thoughts?

 

[vxs93]

I think it would be something to do with the front discs. When you are braking going down a hill the brakes are constantly working to maintain the cars speed as opposed to when they are being used to slow the car down. I would think because the brake system is under more stress and is constantly working you would feel any warpage in the disc a lot more than you would if you were braking normally. I'm not 100 percent sure if I'm correct I'm just stating what I think the problem could be.

 

[glenn l]

Either discs or front castor bushes.

 

[Cashman_309]

If its only on a downhill then its castor bushes if its braking from 70-80 on any angle then its discs.
Do you notice if the shuddering lessens or stops as you get slower or does it still feel like there is something lop-sided?

 

[david dubbo]

plus 1 for castor bushes

 

[Pollushon]

Either discs or front castor bushes.

Or both. LCA to chassis bushes can cause some wobble under load too.