VX steering shudder when braking/shock absorber replacement

[VFCalais2017]

Hi everyone

I've titled this thread accordingly as I'm not sure if it's brakes or suspension or both that are causing my issue.

Over the past 6 months I've noticed that my steering wheel shudders and vibrates when braking at high speeds (around 70km/h and upwards). The brakes work perfectly, it's just the shudder.

A common problem I've been told with the VT and VX is that the front discs warp and you have to replace them prematurely. I've had 3 sets of front discs on my car to rectify a similar issue.

I've always used the standard DBA or BOSCH rotors on the front. They're relatively inexpensive and have done the job well as far as braking power is concerned. I'm happy to change the front rotors again if this is the issue.

At the same time though, I'm wondering whether it's suspension related. There are no distinct rattles or knocks in the suspension however the ride is not 100% quiet. Being a Calais, the ride should be smooth and quiet. On smooth roads, the car glides and floats like you're on a cloud. On roads with an imperfect surface, I can feel and hear every imperfection in the road surface. It's not unbearable but noticeable and annoying.

I've replaced front torsion bars and the hydraulic bushes on the front. All shock absorbers were replaced at 120,000kms with genuine Holden (Monroe) parts. The car now has 245,000kms which leads me to believe that they may be due for replacement. I can do the work myself but it's cost of parts and a wheel alignment afterwards that is a concern given that it's a second car and may be retired next year.

The front discs haven't done a lot of mileage and so I'm wondering if suspension or shocks could be causing the issue.

Are there any simple tests that can be done to check for issues? I know the bounce test for the shock absorbers. I also test the torsion bar bushes by getting someone to drive the car forward slowly and suddenly hitting the takes and checking the front wheel movement at the guard.

I've never replaced any other suspension bushes on the car other than torsion bar bushes and the shock absorber ones on top of the tower.

Any ideas or suggestions would be greatly appreciated.

Thank you!

 

[Pollushon]

What you describe is 99.9% of the time caused by rotors. If this is a regular occurrence, you might want to look at the front wheel bearings, it's a floating design and if they are stuffed they could be causing premature run out. It only takes one to cause brake shudder. A tell tale sign is consistency, does it shudder the exact same way from the exact same speeds?

 

[lout]

shudder when braking through steering wheel is usually front rotors
shudder when braking through whole car is usually rear rotors
when you replaced the struts did you also replace the top cushion mount
what are the tyres like and brand
i assume you have checked for wear in the steering

 

[VFCalais2017]

What you describe is 99.9% of the time caused by rotors. If this is a regular occurrence, you might want to look at the front wheel bearings, it's a floating design and if they are stuffed they could be causing premature run out. It only takes one to cause brake shudder. A tell tale sign is consistency, does it shudder the exact same way from the exact same speeds?

Thanks Pollushon,

Sorry, there's so many things I've done to this car that I couldn't list them all in my other post about the idle issue, but yes, I replaced both front wheel bearings/stubs with genuine Holden parts around the 200,000kms mark.

The shudder is consistent at the same speeds although I have noticed that is much more prominent when going downhill.

Around town driving at 40 to 60kms isn't an issue. It's when trying to stop the car at high speeds that it's an issue.

 

[VFCalais2017]

shudder when braking through steering wheel is usually front rotors
shudder when braking through whole car is usually rear rotors
when you replaced the struts did you also replace the top cushion mount
what are the tyres like and brand
i assume you have checked for wear in the steering

Thanks Lout,

Yes when I did the front shocks I replaced the top cushion mounts/bearings. These were all genuine Holden parts too. These were done 120,000kms ago so it might be due for a replacement.

Holden shocks are quite expensive though. Are there any good quality alternatives like Monroe, KYB or Gabriel?

My gut instinct is telling me that the shudder is caused by work front rotors. They're a few years old now and would have done around 40,000kms. I'll check my receipts though to see when I purchased them.

 

[lout]

are you a late braker, some people wait until the last minute and then push hard on the pedal
this creates a lot of heat which then when you stop is localized to one part of the rotor
if this is the case, try braking a bit earlier but with less force
do your rotors look like these

What Causes Brake Rotors To Warp? | Brake Experts

There are two standard categories of brake rotors:

brakeexperts.com

Heat damaged rotors

www.chryslerminivan.net

 

[Heavy VT]

Can you feel it through the brake pedal?
Is the pedal pulsing?

 

[VFCalais2017]

Can you feel it through the brake pedal?
Is the pedal pulsing?

Hi Heavy VT,

No to be honest I can't notice any pulsating through the pedal. Even on previous occasions when I replaced rotors it didn't pulsate.

I know what you mean though. We have a vintage vehicle that did that many years ago and what we thought was a poorly machined drum or bent axle turned out to be a twisted wheel rim that was pulling the drum out of alignment when fitted.

 

[Heavy VT]

That suggest that it's not the rotors.
I would check tie rod ends, rack ends, rack mounts, worn bushes in the rack, lower control arm bushes and ball joints.

Probably better off taking it in for a suspension check at a suspension place.

 

[VFCalais2017]

That suggest that it's not the rotors.
I would check tie rod ends, rack ends, rack mounts, worn bushes in the rack, lower control arm bushes and ball joints.

Probably better off taking it in for a suspension check at a suspension place.

Thanks Heavy VT,

Yes, I was considering doing that too because they'll be able to point me in the right direction and check everything over. Not easy with just a trolley jack, ramps and stands!

I might call Pedders. Thats the name that springs to mind... pun intended

Cheers!