I began the replacement of the rear brake pads on our 2012 XF and had acquired the proper tools to rewind the calipers. However, instead of rewinding the calipers I went the wrong direction on the left side (back brakes). Once I realized this, I am having a very difficult time reversing my errors and I do not want to do damage to the piston. Any suggestion as how to wind back the caliper at this point? I considered taking the caliper to my workbench, but disconnecting the electronic parking brake mechanism looks difficult.

Thanks,
Jim

 

After more research on the Forum, I learned that the left caliper turns clockwise to retract. I assumed that I needed to use the left side tool which probably destroyed the caliper. The piston is apparently wedged as I cannot turn it clockwise now.

I plan to ordering a replacement caliper. I do know that I will need to take the tension off of the parking brake cable (even with the parking brake off) in order to detach it from the old caliper and attach it to the new one. Any guidance on that process will be most appreciated.

Thanks,
Jim

 

If I remember right, once the caliper is off the hub, it just unhooks - definitely nothing to panic about
S Type calipers are identical, I got mine from a scrapyard/breakers for £20
check out ebay too

 

When I turn the pistons the wrong way the only thing that happens is they turn but don't move in?
Never got them locked up before so surprised at that.
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Are you shoving as you turn it?

 

I am putting pressure on the piston using the tool. But I actually am unable to even turn the piston at this point. I might give it another try, but I really feel that I probably have damaged the the piston and/or caliper.

 

Quite possibly.

In which case as far as I see it, you don't have much to lose in increasing the force, especially the rotational. See if you can hook up the equivalent of a small cheater bar to the tool and see if you can wind it back in (the correct direction) with that.

 

I will give this additional pressure in the morning. I will let everyone know the results. Thanks for your suggestions.

Jim

 

I did the right side caliper without too much trouble. The initial effort to wind back the piston took some effort, but then went pretty easy. I went back to the left side and used a pry bar on the caliper and vice grips on the caliper tool. I placed multiple times the effort that I used on the right side but still no movement. So I am ordering a new caliper tonight.
Some good news is that I was able to compress the arm that goes to the parking brake and detach the parking brake from the left side caliper. After looking under the car, it appeared you would need to dismantle much of the under carriage to access in order to disconnect the the parking brake cable.
Again, thanks for the advice and encouragement.

Jim

 

Worth a try...
If buying new, remember s type brakes are the same. They might be a bit cheaper cos they’re out of date
And don’t forget the copper washer for the banjo bolt - I had to reuse my old one

 

I appreciate the information Bigv. I ordered a reconditioned caliper at RockAuto for what seems a reasonable price. The description notes that the copper crush washer and banjo bolt are included. I will update on the final step of this project.

Thanks to all.
Jim

 

And as I learned when I upgraded the rear 326 mm brakes on my F-Type to the 376 mm brakes, if you are lacking new crush washers just file the raised inside edges off the old ones, add a thin spacer washer, and you are good to go!

 

Crush washers are cheap and widely available.

It's possible but a bit daft to anneal and reuse them.

 

Try finding them here in l'ol il' Adelaide!
Believe me I tried and tried and could not find the correct ones anywhere.
I desperation I even ordered four new ones from the local dealership (the one and only JLR dealership within 700 km of me), they said they had to come from Sydney and it would take a few days and they would call me when the came in, and they wanted to charge me $9 EACH! I never did get a return call, meanwhile my one and only car (the F-Type) is sitting on axle stands with no rear brakes so I was desperate.
I first tried refitting the crush washers as is but no go, brake fluid leaked out around them.
I then added a 1 mm thick washer - better but still some leakage.
I then filed the ridges off the inner edges of the crush washers and added the 1 mm washers, hey presto no more leaks!
That was just on three years ago now and the brakes have been perfect ever since with zero leaks.

 

You can probably anneal them by leaving them out in the sun there!

 

Also once finished and all back together unhook battery for a couple of minutes this will allow reset of parking brake module adjustment,press brake pedal a few times to bring pedal pressure up before turning
on ignition,then turn on ignition not starting the car yet and while holding down brake pedal activate parking brake that should calibrate parking brake module then good to go !

 

The O-ring that seals the piston to caliber housing is square, this forces the piston to return to the neutral position when the pressure is released so the pads don't drag,I'm thinking the piston moved out to far out as you say and now the o ring is not in place . Its not a easy job to get it back in place without damaging the seal, a new caliper is the best idea.

Randy

 

I installed the new (reconditioned) caliper yesterday afternoon without any issues. By the way the caliper from RockAuto included the crush washers and a new banjo bolt. I bled the brakes and disconnected the battery to calibrate the parking brake module. I took it for a test drive today and everything seems fine although the job required a little more effort than I anticipated. Thanks to everyone for their help.

I noticed that the outside pad on both calipers was worn considerably more than the inside pad which seems to the outside pads were not adequately releasing. I expect the pads and pins should be lubricated periodically to give a longer life to the outside pads.

Thanks again,
Jim