Is this a seized caliper or worn bushes?
 

My symptoms are:
Vibration through the steering wheel on breaking at high speed, then even after breaking the vibration continues at any speed.

Stop the car, drive off, no vibration at any speed, break at high speed at vibration starts again and stays at any speed until car is stopped for a while.

Can a seized caliper be intermittent and only seize after heavy breaking, the release when the car cools down a bit?

I am leaning to bushes as the vibration doesn't change it's frequency with speed, it's quite a low frequency vibration at both 20mph and 70mph, also no caliper/disk gets hotter than the others.

What do you guys think it is? (ruled out balancing as it does this on 2 different sets of wheels/tyres both sets balanced multiple times and one even road force)

have your rotors checked

Something loose in the suspension, like control arms or tension struts. Braking will typically set it off, ie initiate the vibration.

There is nothing to release the caliper except the rotor runout pushing the pad back in. If it was seized, it would stay seized.

Can rotors cause vibration when I am NOT braking? I didn't think they could

Thanks, I see. Is there an easy way to check suspension parts? Like jack up front and try to rock wheels left/right up/down?

With the vehicle off the ground and properly supported on jack stands, get underneath and inspect all bushings. Each end of both the control arms (rear, front wheel) and tension struts (front, front wheel). See if anything moves when you lever on it. It may not, you may just see a tear in the bushing, or other signs of wear. There doesn't need to be much play to allow a shimmy under braking. The bushings come pressed in, you buy new control arms.

thx dude. I will try this tomorrow

Okay, there is lots of play in the wheels when rocked - perhaps 3-4cm either side. The tension strut bushes are visibly the source as you can see them deforming when someone rocks the wheel.

I have bought lemforder tension struts and ball joints as it makes sense to change them too.

Question is, if changing the struts AND balljoints, do I need to separate the old balljoints from the old tension struts to remove from car or can I get the whole assembly off the car in one (i.e keeping old bj attached to old strut). I ask as I don't have a bj splitter.

Thx

those balljoints are bolted to the knuckle. the tension arm and that bushing are one piece and then you need to take off the balljoint after that. dont forget to keep the big bolt that goes through the bushing loose until you put the x back on its wheels and give the front end a few thrust to the ground....then you tighten them up. taking off the lower plastic shroud will help and using a flex joint with an impact gun. good luck

Thanks for the reply, I was able to do it as I thought - i.e. Unbolt the bj from the knuckle without splitting the bj from the tension strut - once the tension strut was disconnected from the chasis, it can swivel on the bj giving lots of room to undo the 2 bolts holding the bj to the knuckle.

My problem however is that the bj unit is so badly seized up in the knuckle that it won't come out anyway!

It's going into a garage tomorrow to get the bj's done and I think I'll do the other lca's while it's in there.

Sucks because I thought my problem would bd splitting the bj from the tension strut but that was really easy in the end and I wasn't even trying to split them!