Vibration

[is200 Newbie]

I am getting a bit depressed with this fault now

When braking the steering wheel vibrates/judders - the feeling you get when the discs are warped. Having not long replaced old discs (approx 2000miles ago) with new brembo ones the problem presented itself.

I have changed and cleaned practically all the parts that i can on the caliper and cleaned all mating faces (hub to disc/disc to wheel) replaced the slide pins with new - re-greased all / checked calipers and everything is working as it should.

The solution to the problem can be to replace the discs again but these should be good discs i am thinking? I have been told today that there could be other issues causing the vibration/judder under braking such as front hub bushes, track rod ends, tie bars, wheel bearings.

Am i being fobbed off or could there be other causes that would replicate the feeling of warped discs?

Anyone know of any links to any pages showing a step through of the work that needs doing?

[kenfoxy]

You haven't mentioned brake pads. I take it you changed those when you fitted the new discs. Also have you checked the wheel balance?

[is200 Newbie]

Thanks for the reply

yes - new pads (Mintex) - New discs (Brembo) - New slide pins from Lexus (not cheap) tyres have been balanced and aligned and pressures are ok.

So i am at a loss as to what could be the fault other than the discs but with them being brembo which is a good quality part have no idea of what else i can do.

[is200 Newbie]

One thing i have noticed which i think will have some bearing on the matter is that when first starting the car in the morning for a few miles under braking then its as smooth as a nut but after that the judder is back.

But if i drive for a few more miles, 10 miles or so, the judder has gone when applying the brakes but then presents itself again a few miles down the road when applying the brakes again. It is as if when the discs are cold they dont have the feeling of being warped but as they are being used they are heating up and warping. When driving around not using them they are cooling down until used again?

Does this point to warped discs or am i looking at other issues?

[andy w]

could you have a faulty caliper ?

[wayne-m0]

Mate,

This is a common fault on older models. I had exactly the same problem with mine.

Simple answer. It was a sticking caliper. Brakes do not come off completely when braking, disc heats up and warps both disc and grooves pads.

Replace caliper. Easy way to check. Once the car has done a few miles, touch each brake disc carefully as you may well find one is very hot and might even smell slighly of burning. You will certainly notice the difference if one of the discs has been rubbing against the pads.

My gearstick vibrated badly when braking as well as the steering wheel and after a while, even when driving down the road without braking the wheel vibrated, the discs and pads were that badly affected.

My disc after running was roasting hot on the front nearside. Changed caliper on front nearside as well as new set of discs and pads on front and all is well.

May get front offside changed in time too as the garage suggested as both look similar age, the other may well start to stick in time.

Shame the IS has this weakness it did get me down for sometime till the problem got sorted!!!!!

Hope this helps keep us posted if this works!

[is200 Newbie]

Thanks for all the replies

Problem sorted. I popped the caliper pistons out at the weekend (all 4 of them on the front) - none were seized but i think some may have been sticking?

All pistons were spotless, no rust/pitting etc so i cleaned them up and re-inserted them into the caliper and bled the brakes (lost a lot of fluid doing this). I put a bit of WD40 in the rubber dustcap and left them overnight after testing to see if all the pistons were working. Just done a 10 mile drive and the brakes are spot on.

Saved just under £600 on a set of new ones from Lexus