Sounds like brakes are on while driving

[johnnyoro]

There is no " air gap " the pads will always rub on the disc , however they should not rub too hard it is the flexing of the calliper seals that hold them in position.
Try chocking the front wheels and then jack up the rear , you should be able to spin the wheel easily and just hear a light rubbing sound. If not then you may have some part of the mechanism that is sticking. Although you have had it checked by the dealer so it should be ok
If you are still unsure then take it to a fast fit place they will usually allow you to be there when they spin the wheels
Hope this helps

[daveaasmith]

Personally I do maybe 100 miles per week.

It feels to me like the EPB needs winding back fully and it’ll all reset itself but I know that won’t happen. Or strip down, lube, and refit - in case the pads arent able to slide back fully. But Toprivetguns you’ve done all this without any change.

New calipers and a new set of EPB motors maybe but that’s extreme!

[Toprivetguns]

Originally Posted by johnnyoro

There is no " air gap " the pads will always rub on the disc , however they should not rub too hard it is the flexing of the calliper seals that hold them in position.
Try chocking the front wheels and then jack up the rear , you should be able to spin the wheel easily and just hear a light rubbing sound. If not then you may have some part of the mechanism that is sticking. Although you have had it checked by the dealer so it should be ok
If you are still unsure then take it to a fast fit place they will usually allow you to be there when they spin the wheels
Hope this helps

https://www.theimi.org.uk/trw-passen...parking-breaks

3rd paragraph 6th line down. RE: Air Gap

[daveaasmith]

Interesting re calibration. So either the unit isn’t getting it right (in mine and your case) or the manual calibration steps are at fault. Maybe!

What are the calibration steps? I’ve just watched a YouTube video and it seems like nothing more than (when replacing pads or stripping to clean):

Callipers bracket off, EPB motor off, screw motor fully in until it stops, push piston back in
Engine on, press brake pedal loads, cycle EPB on/off a number of times

Is that it?

With my car I think the excessive heating of the rear disc/pad then makes the brakes squeak loudly when I’m coming to a standstill. For a car with brakes which are less than 5k miles old that’s not how it should be.

I worry I’m turning into a right whinger but the noise(s) are doing my nut in, cos it’s the best car I’ve had for ages!!!

[johnnyoro]

The "air gap " that is mentioned in this article may wel apply in some brake applications however in car disc brakes when the hydraulic piston is pushed against the pad and disc and released it is only the flexing of the rubber seal that allows the piston to move back ever so slightly , but the pads will still remain in contact with the disc
This contact should be very light and the wheel should spin freely
I have changed disc and pads on lots of vehicles and the rears on several xc60,s
Using a service tool via the obd port and had no problems .
If you check on YouTube and on this forum there are several methods that are used to deal with the EPB , some use a battery and others remove the EPB unit
But none mention any problems with calibration

Hope this helps

[daveaasmith]

Thanks Johnnyoro. I get that this is how it’s supposed to work, but in our cases it’s sadly not. What are you thinking the fault may be?

[johnnyoro]

If you are happy to take the rear brakes apart then remove the pads and caliper bracket give them all a good wire brushing. When checking the pads use some emery paper or a file to put a small chamfer on the leading and trailing edge . Most brake squeal is caused by a hard 90deg edge at these points
When reassembling put a small dab of copaslip or similar on the ears of the pads . Make sure that the slider pins move freely.
Most people will also put some copaslip on the parts of the caliper that contact the pad
Also worth checking is that the brake back plate is clear all round although if it is touching the disc that would be pretty obvious
When all is back together and after applying and releasing the brake a few times if you can get someone to use the footbrake while you spin the wheel the brake should release the instant that the pedal is released and spin freely . if you have awd then you can expect some drag from the transmission
Hope this helps

[daveaasmith]

Any lube needed on the piston or seals at all?

[johnnyoro]

Hi unless the piston gaiters are damaged I would tend to leave them alone . When you push the Pistons back they should move smoothly . If they don't , have a look behind the gaiter , and any sign of corrosion means new caliper .
If the gaiters are ok there should be no problems

Hope this helps

[Toprivetguns]

Originally Posted by johnnyoro

If you are happy to take the rear brakes apart then remove the pads and caliper bracket give them all a good wire brushing. When checking the pads use some emery paper or a file to put a small chamfer on the leading and trailing edge . Most brake squeal is caused by a hard 90deg edge at these points
When reassembling put a small dab of copaslip or similar on the ears of the pads . Make sure that the slider pins move freely.
Most people will also put some copaslip on the parts of the caliper that contact the pad
Also worth checking is that the brake back plate is clear all round although if it is touching the disc that would be pretty obvious
When all is back together and after applying and releasing the brake a few times if you can get someone to use the footbrake while you spin the wheel the brake should release the instant that the pedal is released and spin freely . if you have awd then you can expect some drag from the transmission
Hope this helps

All of the above carried out. The path I haven't taken is replacing the brake lines incase they have collapsed internally which I highly doubt.