I have a 2008 4.2L normally-aspirated XF that I've owned since new. After failing to reset my "handbrake inoperative" warning by following the given procedure, my inspection of the rear pads revealed that driver's side (right) is less worn than the passenger side. I've just pulled off the pads and tried to mount a new set. To retract the piston, I've tried pressing it back in with a large G-clamp - with a long drain pipe over the loosened bleed nipple, to prevent the master cylinder's reservoir from overflowing. The piston won't budge. How aggressively can I press on that damned piston? Many thanks in advance for any other words of advice that you might offer in addition to this.

No obvious signs of corrosion

 

Welcome to the forum Mike,
I've moved your post to the XF technical section.
Please post an intro in the new members section when you can.

You will need to rotate the piston as you are pushing it back, there are special tools available to do this or it is possible to do it manually but a bit of a scutter.

 

+1

The wind-back tool is not costly and makes it easy.

 

Thank you for the fast response Norri, I'll make a note of completing the intro. Regarding the brake piston, is there a required direction in which it should rotate?

Okay, edited a few minutes later after looking for a video, now that I know the piston must turn. I found this and it explains the process very simply. In addition, apparently the right-hand piston retracts clockwise, left-hand piston retracts counter-clockwise - going to try it now.

I'm amazed, because I've always done the services of my BMWs (which had the traditional piston on the rear brakes) and had the Jag done at the dealer. With the age of the Jag now - and being retired (i.e. poorer), I've decided to tackle the service myself. Paying in ZAR makes even cheaper tools a bit of an investment decision - but I'm pretty handy in my workshop, so will probably make one for the next time.

 

Hmmm. It turns out (pun intended) that the left-hand piston should NOT be rotated counter-clockwise - because that makes the piston extend outwards. So on this model, the left piston must be retracted by turning and pushing (if using a large, long-nose pliers, some heartfelt exclamations of encouragement seem mandatory) in a CLOCKWISE direction, the same as the opposite side. Nothing seems to happen for a while because each piston seems to have to be absolutely convinced that you are not going to give up. Even having used four layers of toweling between the pliers handle ends and my palm, my hand is sore - but each piston eventually retracted gracefully after the initial, protracted dispute. I'll definitely be making/buying the tool if I have to do this again.