Dear all,

I'm about to replace the pads all around for the first time on the XJ and I'd appreciate some help. Is there a sensor at the front and rear? Is it one, two or four? There are sensors that look a bit different. Which one is correct or are they different for front and rear?

 

zYx, before you go buying parts, there is a big question that you need to know the answer to: Do you have the upgraded brakes? These are standard on the 5.0L supercharged cars and all other cars should have the smaller brake package. So, when buying parts, you need to make sur ethat you get the correct parts They are not interchangeable unless you do a complete swap (ie, calipers, rotors, pads and probably a few other components). With this being said, you have 1 sensor for the front end and 1 sensor for the rear end. I forget which wheels they are on (I want to say right front, left rear) Atleast on the smaller brake package you are going to need the upper sensor you show as the silver part gets slid into the pad and friction holds it there as the rest hangs on the outside of the pad. In the case of the bottom, where you see the copper, that part gets slid into the groove in the pad with the raised section going towards the rotor. These work by simply letting a metal component of each reach a point where it starts touching the rotor. This then completes the circuit for the ABS system stating that the pads are too well worn and need replacing.

 

The brake pad wear sensors are on the front left and rear right wheels, on the inner brake pad in both cases.
Your top pic is of the pad end of a rear sensor which slots into a spring which in turn slots into the top edge of the inner brake pad.
Your middle pic is of the electrical plug connector of either a front or rear sensor, they are the same, which plugs into a connection high up in the wheel well.
Your bottom pic is of a front sensor where the bit at the bottom of the pic is the part that plugs into the top of the inner front brake pad, it plugs straight into a slot in the pad with no spring involved. But be careful plugging it in, it can be very brittle and snap off if you are not careful or you don't go in dead straight.
I *think* the sensors are the same for all XJ X351 brakes (ie SC models have 380 mm front brakes and 376 mm rear brakes while others have 355 mm front brakes and 326 mm rear brakes) but don't quote me on that so it's best to take Thermo's advice and double check exactly which brakes you have before ordering/buying pad wear sensors.

 

THIS may give you a idea

 

just Curious. how many miles on your pads. Thanks

 

One other bit of info? If you change pads BEFORE you get the low pad warning. You can just reuse your factory wear sensors. If not then you must replace them or if you don't want to mess with this ever again. Just connect the two wires together to complete the circuit and tuck those wires back out of the way.
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That's a good tip. Also, if your Jaguar dealership is being difficult, there are matching duralast part numbers you can just get from regular chain stores. The length is different but it works, I have the rear one installed currently.

 

Thanks Thermo, these are just standard brakes

You're right, 355 for the front and 326 for the rear.

I saw this and I couldn't really see what type of sensors they used

No idea. I bought it when it had 49k miles on the clock and it now has 62k.

I did think about doing this. I actually tucked the wires away in my previous car. There's no way I would let my pads wear that much to get to this point.

Thank you.

 

brake pad sensor I will warn you also as I've got a 2013 xj and just replaced all 4 pads on my car but the front sensor you have shown with that Red insert I would check the front sensor connection first cos the amount of trouble I had kept ordering sensors cos they didn't fit the plug in the end I had to pick out that red insert with a twizer to make it look like the front sensor plug I just took off so plz check the front sensor plug first plus if you are going to do them yourself. Just watch out as I heard that doing them yourself can cause the brake booster to fail as well cos mine has and it's £900 to replace so good luck

 

The brake booster will not fail if you do a brake job?
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I have heard that people have had issues with their ABS after doing a brake job where they have forced the fluid back through the ABS module when pushing the piston back into the caliper. BUt, this is easily overcome by simply opening the bleeder port and letting the extra fluid go out the bleeder port vice being forced back through the system. Granted, I have always forced the front fluid back into the system with no issues over the many, many years I have been doing brakes. I normally bleed out through the bleed port for the rears just to make retracting the rear piston easier.

I can see where this would be an issue if you have say some metal flakes or something of the like that has deteriorated inside the brake line. This could block the pulsation circuit inside the ABS module. Granted, can't say I have heard of issues getting all the way back to the brake booster.

 

Great info. Thanks

 

Noted. Thank you.

For the first time in my life I managed to get brake pads worn warning ⚠️ on my dashboard the other day and I haven’t got the new kit yet… It’s ok, there’s still some left 🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️

 

If you have the dash board warning it's too late. You have worn the sensors out and they will need to be replaced or eliminated.
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Too late to keep the sensor but there's still a few miles left on pads until I get the new kit delivered and replaced.

 

I apologize if this has been answered in some other thread, but I'm about to embark on replacing the front brake pads, and the rear pads and rotors on my '11 Supersport. Does the EPB automatically switch on when the car is put in park? If so, then I assume I need to put the car in "brake maintenance mode" before starting the job? And from what I've read, the EPB only affects the rear end, not the front? Thanks! This forum/group has been invaluable in not only my quest to find my Jag, but also in helping me maintain it. I can't thank you all enough!!

 

I've just done the front and yes the EPB is only applied to the rear and I'm yet to do the rear but they're not due yet.
I've read somewhere that you only need to release the "handbrake" and once disks (rotors) are replaced you have to apply and release the handbrake twice (or a few times) and it'll calibrate itself. Don't quote me on that so I'll wait for someone more experienced to give feedback on this.

 

Thanks zYx. Did you try to put the car in brake maintenance mode, or did you just jack it up and get to work?! Ha!ha! I've worked on our Mazda where the EPB kicked in, and that's a pain the @$$.

 

I didn't put it into maintenance mode at all. I did apply the handbrake to secure the car so when you do the rears you'll have to find another way to stop the car from moving.

When you get to it, either front or rear, don't forget to remove the cap from the brake fluid container (for when you push the pistons back to make room for new pads). I forgot and then I saw a puddle of brake fluid on the floor 🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️ crapping myself that I ****ed up big time. Fortunately, it seems that the fluid leaked out through the cap and not a broken line somewhere 😖🤬

 

When I have done the pads on my 2012, the brakes will not automatically apply themselves. So, park the car, set the parking brake, block the front wheels (front and back), then jack up the rear end. From there, you can release the parking brake and do a pad replacement like you do any other vehicle. You then have 3 options for resetting the EPB:

1) use the SDD software to tell the computer to do a EPB calibration
2) disconnect the battery to force the EPB module to lose its memory, forcing the car to do another calibration,
3) before putting the wheel back on, use a screw driver or other similar rod to manually actuate the parking brake lever. pulling the arm towards the front of the car numerous times until it only goes part way (repeat for the other side).