shudder in front end

can you put your old rims/tyres back on to see if the problem dissappears....................

May sound silly but I take it you have checked the wheelnuts?

Also check the caliper retaining bolts, wheel bearings for play and so on.

For it to go away when more brake force is applied seems like a bearing or caliper retaining bolt to me.

Rob

Hi Bundy.

It sounds like the brakes are heating up my FIL had the same problem with his ford, went to the local mechanic machined his rotors and put new pads on and the problem came back after about six months got to the stage he couldn't drive it any more.
I put new rotors on and pads did the wheel bearings cleaned the calliper slides the pistons were free flushed the brake fluid and all has been good now for over 12 months.
That may be the same problem as what you are having it may be worth replacing pads and rotors with new ones also check your steering damper.

cheers Pat

Quote: "20 thou ago new rotors.and pads.(have just been spun up .3 out no hot spots."

Not quite sure what you are trying to say here, but I read it as you have checked the run-out of your rotors, and they run-out .3 (mm?).
If that's correct, I reckon that's your problem right there....warped rotors.
.3mm is quite a lot of run-out....you would certainly feel that through the steering wheel.

Cheers
Glenn

Check Tie Rod Ends.

.

Hi, i have had the same thing in my GU when running 35's and found that the front panhard rod bushes were flogged out. I now replace them every 12 months and have not had a problem since. Also make sure the wheels are balanced regularly and you should be right.
cheers.

Steering damper okay?

Sounds like the rotors to me but failing that I would say check the bushes... bigger tyres means that the problems that might have gone unnoticed with standard road tyres show their ugly head and are difficult to track down...

I had a falcon do the same thing and it turned out to be contaminants on the rotor... wheel would nearly be reefed out of my hands... you could always try cleaning the rotors up with brake cleaner, making sure your inner axle seals aren't putting any oil in there and seeing if it makes a difference..

And just because you paid a lot for the pads and rotors 20k ago doesn't mean they are not the prob as mud will quickly put end to pads and rotors if left to grind away.

cheers

G'day Bundy

I just got off the phone to my son Shane, he works for Pedders Suspension as a front end technician, he has just been through the same problem with his GQ, he told me to tell you it is most likely the swivel bearings, as a tempory fix if you look on top of the swivels you will see a plate with 4 bolts, you can remove the plate carefully making sure you allow no dirt to enter, you should find 2 shims in there , you can try removing the thinnest shim and see how that goes, if no good you will need to replace the bearings , which apparently is quite a big job, but still doable by yourself if you are handy with a spanner...hope this helps ...if you need any more help let me know and i'll drop you an MM with my phone number ...

Cheers......Borgy

Once you have confirmed your wheels don't have excessive runout, try to borrow another set of similar size wheels and tyres that you know don't vibrate and try them. If the problem goes away then your tyres might have what is a called a force variation problem. What this means is that the tyre doesn't flex at the same rate around the whole carcass. Its like there is a hard spot in the tyre. Under light braking and slow speeds you usually don't notice it as the tyre just rolls along but when you apply heavy braking or higher speed you force the tyre to flex more and it develops the symtons that feel like an out of balance wheel, hence the shaking. If that is the problem (and you have checked all your bushes, bearings etc) then the only cure is different tyres. Having said that the same symtons can occur if the tyre is not seated properly on the rim. You can usually balance the wheels and they appear ok but as soon as you force the tyre to deflect then the problem shows up.

The force variation thing was a real problem on VB commodores and they kept special best quality tyres for the ones they coudn't fix.

While loose bearings, bushes etc don't cause the problem they allow it to become worse which is why all that stuff needs to be checked as well. Same with steering dampers.

regards

Andrew

Have a read on my site here.
Disc Thickness Variation
Machine the rotors and have them set up correctly will fix the problem. It they are not fitted correctly it will re-occur again in as little as 10 000 km.
Hope this helps
Scott

ok to all whom advised a big thank up ............all was taken on board .for the next unsolved shudder ......
Well changed brake pads........were bendex 4x4s ......now farrero4x4 problem solved......the old pads were and still are nearly new and look great....but don't know why but alls good now



Bundy..with thanks

Other things to check that are known causes of the dreaded GQ shudder:

Steering box chassis mount crack (a beefed up 'bolt on' mount was offered in a recall). Radial arm bushes, especially if they are poly. Visually, they can look o/k but they can have too much freeplay.