Shimano Caliper QR Play

Hello, can anyone advise? When closing the QR on my Ultegra SL front caliper after switching wheelsets earlier, I noticed it didn’t stop as normal in the closed position. The washer with the little stop/lip wasn’t engaging properly.

Now I’ve realised that this is because there’s a few mm’s play where the QR passes through the caliper arm - from the lever in front to the anchor bolt behind.

I’ve scoured all the tech docs, and when it’s one of the models where there’s no screw in the middle of the QR cam e.g. Ultegra 6600, 105 5700, Tiagra 4600, there’s no indication of how this thing is constructed. Is the circle in the middle of the QR cam a cover over an adjusting screw? Is it some sort of press fit? WTF?

Here are 2 photos illustrating the amount of play - one pushed through from the front which leave the stop washer dangling, and one pushed through from behind showing the QR cam away from the caliper arm.

Can I fix this? Is it simple? Or is it fucked?

PS. When I’ve been braking hard in recent months, I’ve assumed the little cracking noise that happens very oocasionally was headset spacers rubbing, or weird spoke shit, but now I’m wondering if it was this thing working its way loose…

I’ll ask a mechanic tomorrow anyway, but it will help me sleep tonight if anyone online knows anything about this.

Mid-morning bump...

Well, I’m not taking any fucking chances, so have bought an alternative. It’s bad enough people using break instead of brake in their posts, so I don’t want any confusion over which is fitted to the front of my bike.

Thanks for looking.

Sorted then? I am curious because the earlier q/rs are easy to strip down, and I have never seen one worn. Seized often, but never with excess play.
But I have never tried to dismantle one of the later ones, so I was hoping someone would have come up with an answer.
Never mind.
Enjoy your new breaks. Just pray they don't brake.

I couldn’t come up with any definitive info, and had to assume it was one of Shimano’s famously non-servicable parts that just works in 99.9% of cases :/

I expect there’s a screw under the press in ‘button’ in the middle of the QR cam, but there’s zero space with which to pry it open, even with the most Creosotean tool.

That’s the braking news.