Electronic Parking Brake

[Jinxie]

Hi all,

Is there any possibility of damaging the EPB mechanism in the calipers by using the 12V battery trick to release the brake? I just wondered, because having applied 12V to both calipers directly and having them both release apparently satisfactorily, I can no longer actuate the piston by applying 12V. The motors can still be heard running, but they don't move the pistons in or out (trying pos & neg both ways round). Any thoughts?

[green van man]

Don't think so, I wound mine back using a PP3 9V battery, just reconnected the callipers and applied the handbrake to wind them on. Took longer than usual initially but once done the first time all operated as normal.
I wound mine back until it stopped pushed the caliper back and fitted the new pads, reconnected the plug and operated handbrake.

You can do it by hand, but this means taking the motor off.
If you have jammed something it may require taking the motor off to see what it is.

Paul.

[Simon Jones]

There's facility in VIDA to safely wind back the pads.

Some guidance in the articles section: https://www.volvoforums.org.uk/showthread.php?t=206358

[Jinxie]

Originally Posted by green van man

Don't think so, I wound mine back using a PP3 9V battery, just reconnected the callipers and applied the handbrake to wind them on.

Paul.

That's what's bothering me. I used a 12V lead acid battery which may have had too much grunt and stripped the splines! You can't go wrong with a nice weak PP3; wish I'd used one instead.

[Jinxie]

Originally Posted by Simon Jones

There's facility in VIDA to safely wind back the pads.

Some guidance in the articles section: https://www.volvoforums.org.uk/showthread.php?t=206358

I'll be taking the back off tomorrow, so thanks for that pointer. I'm just hoping those delicate splines haven't been stripped.

[Tony500]

I used a 12v boost pack to wind mine in when my laptop was broke so no access to Vida. Winding in can take a little time so I doubt you have stripped them.

[Simon Jones]

When the motors are powered by the car, it monitors the current consumption and stops as soon as the mechanism encounters the correct resistance so it 'knows' when the brakes are fully applied.

[Jinxie]

Originally Posted by Simon Jones

When the motors are powered by the car, it monitors the current consumption and stops as soon as the mechanism encounters the correct resistance so it 'knows' when the brakes are fully applied.

That's what's worrying me. Guess I should have used an inline fuse at least. My only chance is if the motors aren't powerful enough to strip the splines, but I'm not confident of that, even if it is a sensible design criteria.

[Tony500]

Sorry but just re-reading this post.....

You say you can still hear the motor work but the piston doesn't move?
Have you tried pushing the piston in with a tool? Then put the correct power to the epb to see if the piston pushes out?

[Jinxie]

Originally Posted by Tony500

Sorry but just re-reading this post.....

You say you can still hear the motor work but the piston doesn't move?
Have you tried pushing the piston in with a tool? Then put the correct power to the epb to see if the piston pushes out?

I have not yet attempted to move the piston by anything other than electrical means. That's the next thing I'm going to do later today. I'll try 'unscrewing' it from behind first, as described in the photo montage pointed out to me earlier in the thread.