Land Rover Discovery 3 key case replacement

Bought a cheapie key case from eBay. Here’s how I replaced it.

  • Buy case and get the key part cut at a locksmith. You don’t need a specialist car locksmith.
    The new case with key part cut

    The new case with key part cut

  • Assembled and tested but the slightest touch of the key was activating the buttons, so the key was unlocking and locking like mad. Eventually I discovered the rubber studs in the key were activating the circuit board buttons. Glued a piece of card in to insulate it.
    Glued the button studs (super glue)

    Glued the button studs (super glue)

    Weighed down the cardboard with a penny

    Weighted down the cardboard with a penny

  • Still wasn’t working. Provided switch film didn’t have sufficient height to be work properly, so I used the old one.
    Original on right, useless replacement  on left

    Original on right, useless replacement on left

  • Re-assembled the correct way up 2015-05-29-13-55-00
  • Insert the transponder RFID blob in the corner 2015-05-29-13-55-24
  • Fit circuit board and battery2015-05-29-13-55-35

How to repair a brake pad wear sensor

I get pretty annoyed by repairable parts being binned. Brake pad wear sensors often get replaced when they could still work perfectly well, and at up to 50% of the price of the brake pads they’re really expensive to start with. So remove it and look at it, and work out how it works. In the case of this one off a Range Rover, for example:

A worn brake pad wear sensor with the wear link broken

A worn brake pad wear sensor with the wear link broken

It’s easy to see that one of the two wires coming into this sensor are really one loop, exposed at the “sensor” end. When this side of the sensor gets close enough to the brake disc, the metal is worn away, breaking the loop and preventing current from flowing. This is what the ECU senses as it will show a brake warning symbol on the dash. Clean it up and solder it together again:

The same wear sensor with a blob of solder reconnecting the two remaining stubs of metal.

The same wear sensor with a blob of solder reconnecting the two remaining stubs of metal.

Solder is very soft and will wear just as nicely as the metal that was there before, so the “sensor” will still work. Just refit.