I purchased my 850 at (~40k miles) knowing that it had a warped rotor problem, as there would be a little pulsing & vibration from the pedal whenever it
 was braked from high speed - & hardly ever from slow. No big problem there. The rotors were heavily lipped and the pads were down to almost nothing
 anyway, so time for a change.

 I didn't fix the problem straight away as it wasn't too bad & I was waiting for parts from the best source. The thing was, I did need a tyre rotation and front
 alignment, as the car was scrubbing out the passenger side front tyre (on the outside) - and an almost new Michelin was rapidly biting the dust (on
 Volvos that's a pun) thanks to uneven wear. So I got the rotation and alignment.

 Not the expected result- after 15 mins or so of driving (whenever the pads were heated), terrible vibration occurred upon every brake application, from
 high or low speed. This wasn't a vibe that shook the steering wheel, nor did it really pulse the pedal. It felt like applying the brake was pushing a few
 dozen rough rocks into all four alloy rims to stop it (the Lada method?). Needless to say it was virtually undrivable. Who knows what parts I could shake
 loose?

 My auto tech friend said it was like nothing he had ever felt in severity, and half suspected the rear brakes, even though the fronts were so worn,
 because of the way that the car felt. He changed the front discs and pads (more OEM) and the problem was fixed. At the time checked the rear discs &
 pads which were little worn, running true, and the pads had the volvo shims behind them. We left the rear alone.

 It seems I received a few lessons from my story which partially contradict bits & pieces of info on the stories that I have archived on Ozbrick. (I have about
 5 archived threads on my site which talk about various aspects of warped rotors &/or sticky brake calipers. This one is going on next.)

 One lesson is that the front discs can be the culprit in brake shudder even though the steering wheel doesn't shake. That is maybe because the power
 steering (or other FWD stuff?) isolates the wheel from the shudder.

 Number two lesson- It doesn't necessarily mean it's a stuck brake caliper when it takes until warmup before braking starts with the bad vibrations.

 And lastly, a simple & brief removal of a wheel can make a minor rotor problem into a very significant one. Maybe when the rotors warp they are held
 back from warping as much as they can because of the pressure of the wheels, and then they are allowed to "spring out" when a wheel is removed? I
 noticed one recent post where someone had a wheel off and then had problems with brake shudder. Or maybe the wheels were originally torqued
 carelessly, and setting them back on evenly brought the problem out.

 Does anyone have any experience with this wheel removal problem, or any other theories?
 --
 Michael @Sydney

 Michael,

 I had same problem and there is a fix. I suspect it's your REAR brakes. Fire me an email and I'll tell you all about it. If you suspect front brakes I have
 perfect rotors, calipers and near new pads you can borrow for troubleshooting.

 Best way to fix the Volvo brakes is the 17 inch brake kit :-)

Thanks for your response, and generous offer. The problem seems to be already fixed, after changing the front rotors (ATE's were put on). I would have killed to borrow those rotors when I was waiting for the replacements, and I wasn't sure what would fix the problem! Please let me know what the fix is for when the rear brakes are the problem - do you mean the shims or something else?

I saw your other post on selling the R manual. (Drool drool, wipes saliva off chin, stares mindlessly, etc... ) Could I ask what you are asking for it, as I have a friend that helped me get my 850 and now he is in the market for a good one. I have a simple website on the 850 if you want to advertise it there - check the link off my brickboard posts.

thanks & regards

michael