I've had a bit of a day today and was hoping someone could provide some assistance.

My rear brakes started grinding on my 2017 Discovery Sport and I wanted to replace the pads before Christmas. Got pads, jacked up the truck, removed the left rear tire first. I put the truck in N and released the parking brake, took the caliper off, but the piston wasn't compressing. Then I made a major error - I turned the vehicle off which (tries to) apply the parking brake. The electronic parking brake closed but since the caliper wasn't mounted it closed so far it pushed the piston completely out and I couldn't get it to retract.

I ended up removing the EPB solenoid from the caliper and opening the bleed valve, and was able to manually turn the EPB shaft with a socket wrench while I compressed the piston. I then reassembled everything and turned the truck back on. The pedal seemed to feel fine and had expected resistance / firmness.

Unfortunately I received a message that my parking brake required calibration, and to press the foot pedal and activate the emergency brake. When I do this I get a message that there is a parking brake fault and the 'parking brake requires calibration' message returns. The amber ! triangle stays lit, and the red parking brake symbol stays illuminated. I can move the vehicle but it takes some extra effort to get moving, as if the parking brake is still on.

Does anyone have any thoughts or suggestions on how I can fix this or any troubleshooting steps I can take? I have a feeling I'm going to end up having to buy a new caliper / module which looks to be a couple hundred bucks and I'm very afraid I'll end up having to take it to the dealer which is not only going to definitely cost a lot, it'll also probably be a while before they can get me in.

Any help or suggestions will be greatly appreciated!

 

Just as an update, I am fairly certain the parking brake mechanism inside the caliper is ruined to some degree - I don't have a way to open it up and see if something is stripped or a gear is ground down. I haven't been able to find an internal schematic but that's definitely the sense I get when I turn the shaft with a socket wrench and try to extend / retract the piston. Since the parking brake system is faulting with the left rear broken, the right rear brake won't release so there's no way to drive the car at all (not that it would be a good idea with no emergency / parking brake). I guess if I really had to I could disconnect the solenoid / motor on the passenger side too and manually wind back the parking brake, but that would only be in an emergency.

A new (refurbished) caliper was under $200 from BuyBrakes.com, so I decided that would be the best route to go forward and I ordered a new one yesterday. Unfortunately the shipping date is January 12th to 20th, so it will be a bit of a wait. I'm pretty sure the solenoid / motor is fine and this should resolve the issue - we'll just have to rely on our second car for a little while which is no big deal considering my wife and I both work from home. So a bit of a bummer but all in all if you don't count the cost of the Disco being out of service it still works out to less than what it would cost to have brakes done at a legit shop or the dealer. And hey, I learned a hard lesson and won't make the same mistake again.

 

As a final update, this is fortunately resolved and everything is working.

BuyBrakes ended up pushing the delivery date back and couldn't guarantee any timeframe for shipping, so I ended up finding JLR Parts (https://jlr.parts) that had several of the calipers in stock. I ordered on Wednesday and it shipped and was delivered from the UK on Monday morning. The part + shipping cost a bit more ($300 instead of $200) but was worth it vs. having a car that I couldn't drive and no idea when the part would be available. I wish I'd just gone with them initially.

But Monday once it came I swapped out the EBC solenoid, hooked everything back up, and once my wife helped me bleed brakes everything was fine and worked exactly as it should.