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This should be the final problem I've got for the moment.

I've got brake judder over about 60mph. Symptoms as follows:

- Feel a shake when braking at over 60mph.
- No kick through the pedal.
- No shake through the wheel at speed or when braking.
- The discs feel new (no lip), and alledgedly were replaced within 1000miles.
- The shake mainly affects the dash, but does trasmit through the car.
- At the last MOT there was an advisory for 'play in the steering rack'.

I don't think it's the discs. The brakes are super smooth from 40mph downwards, and it doesn't feel like the discs are kicking the pedal into my foot over 60mph. The car cruises at 80mph exceptionally smoothly, so the wheels are well balanced. It doesn;t feel like the steering wheel is wobbling under braking.

It's shaking the dash and that is what's making the car vibrate.

Could it be that the slight play in the steering rack is causing it? Could it be more than slight play?

Let's assume it isn't the discs, what else could cause it?

Gentlemen...start your engines.
 

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My first guess would be track rod ends, as said, when was the last MOT?
 
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best thing to do is jack it up and have a play with ball joints, track rod ends drop links etc see if theres any movement.
 
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Discussion Starter #5
I'll have a look Sunday.

The last MOT was when I bought it in on the 24th December, but as it was done by a garage known to the dealer, you never know what 'slight' means. It's partly my fault, as I jumped on the anchors at about 50mph a couple of times, but nothing faster.

If those things are a possibility then it's well worth a look, I just didn't know if they could cause brake judder, but I'll have a play and see what I find.

Thank you people.
 

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If the discs are fairly new, they may not have been bed in properly and subsequently warped so I wouldn't rule them out, but you'd need a run-out gauge to check them.
 

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I agree with Sphinx -
If the discs are fairly new, they may not have been bed in properly and subsequently warped so I wouldn't rule them out, but you'd need a run-out gauge to check them.
Have a look at the brake calipers see how the piston is sitting and the rubber seals.

EDIT - Is there any excessive heat????
 

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I'd go with the easiest solution, check the wheel balance/alignment. It's 50quid, and you'll need to do it eventually.

Mine was off balance wheels
 

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Discussion Starter #9
I've not had a chance today to look, but...

The wheels are very well balanced. I was doing almost 90mph today and it was 100% smooth, nothing through the steering wheel and no other vibration until I get the anchors on. So I'm confident of that.

I'm almost certain it's gonna be a bush on something not doing it's job, but unfortunately getting rid of my old car took up today's light.

Nope, no heat whatsoever from any of the wheels when moving. I don't do a lot of M/Way driving so it ain't gonna kill me to have a look next weekend.
 

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Play in steering rack causing brake judder?

I have a similar problem, and wondered if the OP ever identified the root cause?

I know that once I get to a certain speed and brake hard, my front wheels start juddering. Braking below that speed is fine.

I am certain it is nothing to do with the calipers, pads or disks themselves. I changed them, with no improvement. Track rod ends are fine. I know there is play in the steering rack – this doesn’t manifest itself much at the steering wheel end, but there is play in the wheels when off the ground and rotated with the steering wheel held central.

On the outer pads on both front wheels I can see that the leading edge is worn away slightly at a an angle for the first 5mm or so, then the rest of the wear is normal. It’s as if the pads are touching the brakes at an angle sometimes, probably due to the excessive wobble. I've not seen this before and it's a little strange.

I suspect that as I brake the wheels start to oscillate sideways. The causes each disk to touch its pads initially at an angle. I suspect that below a certain speed the steering hydraulics resist the movement – but above that they can’t.

I’ve changed a few of the bushes and this helps a little – but it's just masking the underlying problem. I am convinced that the power steering system is worn and not resisting sideways movement correctly above a certain level.

Has anyone else experienced this? Not looking for general advice on brake judder, just this specific issue.
 
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