Since I’ve had my superb it’s had a bit of a brake wobble under hard braking, especially on ACC. Couldn’t feel it through the steering and assumed it was rear discs as ACC uses the rears preferentially.

Was planning on getting them changed at the next service. And then with discovering that carscanner is able to put them in service mode, I was planning on changing them myself once payday comes around.

Curiously I went out in it today and it’s entirely disappeared. There’s a bit of a mental afterimage where I think I can feel it but if I brake whilst consciously thinking about it, it’s definitely gone.

Since the last time I drove it I’ve played about with a few bits of coding but the only one I changed related to brakes was the autohold and hill control sensitivity.

The only other thing I’ve done is remove one of the rear wheels to try the spare then put it back on again.

I would have thought if it was something to do with how the wheel was mounted the I would feel a wobble all the time, not just when braking.

Any other thoughts as to how it’s mysteriously disappeared?

One of my winter wheels falls over if I stand it up, leading me to think it’s not balanced laterally correctly. I also feel a slight weirdness in the rolling which I think is this.

Is it possible to have a rear wheel radially out of balance with the other wheel on the axle, and braking exacerbates it? And perhaps the wheel has gone back on in a different position and it’s now in sync with the other side now?

Even reading this back it feels like a stretch but struggling to understand something which has gone away like that…

1 minute ago, travs said:

One of my winter wheels falls over if I stand it up, leading me to think it’s not balanced laterally correctly. I also feel a slight weirdness in the rolling which I think is this.

Is it possible to have a rear wheel radially out of balance with the other wheel on the axle, and braking exacerbates it? And perhaps the wheel has gone back on in a different position and it’s now in sync with the other side now?

Even reading this back it feels like a stretch but struggling to understand something which has gone away like that…

The only other thing I noticed that I’ve just remembered was one of the wheel bolts was very tight. I had to hang on the end of a 2ft breaker to undo it. I wonder if one is much tighter than the others it pulls the disc out of alignment. Everything is such solid metal I can’t believe that it would.

I’ll get them to check the runout on the discs when it gets serviced in case there’s something in it.

I was also wondering if bolts being done up in order rather than opposites but it also feels like over analysis.

Would be interesting to know if this is a thing. Someone with more engineering experience feel free to tell me just how out of my ass I’m thinking.

But it could be a thing with your bolts being overtightened. Coppergreased torque spec maybe.

New discs and pads fitted today and on a quick test drive it seems to have solved this issue.

Nothing glaringly obvious with the discs or pads. Perhaps slight uneven wear between inner and outer pad on one side. And one disc was stuck on to the hub fairly. But discs appear straight to the eye but I appreciate that they could create wobble with very minor runout that’s probably not visible.

Will let them bed in over the next 200 miles or so then brake hard to be sure.

Well, 200 miles later and the brake judder is back. Im going to jack up and remove a wheel later today to see if that makes it go away again temporarily. If so it points to suspension issue on that corner

Difficult to check, but check that both inner and outer pistons are free to move in the caliper.

2 hours ago, Warrior193 said:

Difficult to check, but check that both inner and outer pistons are free to move in the caliper.

only single piston on rear brakes which I checked when they were pushed in during pad change.

I don't understand how just removing the wheel and refitting can make it go away unless its something suspension and to do with settling with no weight on. I will test it this afternoon.

4 hours ago, Binx1310 said:

only single piston on rear brakes which I checked when they were pushed in during pad change.

I don't understand how just removing the wheel and refitting can make it go away unless its something suspension and to do with settling with no weight on. I will test it this afternoon.

In which case it is possible that your calliper is not sliding freely on the rods - putting most of the braking effort onto one side of the disc and distorting it.

7 minutes ago, Warrior193 said:

In which case it is possible that your calliper is not sliding freely on the rods - putting most of the braking effort onto one side of the disc and distorting it.

all guide pins on rear brakes cleaned and greased well when reassembling.

Just taken wheel off and refitted and the wobble has gone again. Took up to motorway speed, hard braking. Nothing. It can only be something suspension that relaxes when weight taken off when jacking up and then once settled in again allows movement.

I’m off to the airport again Monday so will see what it’s like on a decent run.

Edited 24 April24 Apr by Binx1310