Brake Wear Sensors for E53

[rule1110]

Hi there
I recently had the check brake linings warning come up on the dash so I ordered a new set of after market pads (low dust) for the front and back of my 2005 3.0D X5. I had the mechanic fit them and machine the rotors but when he went to fit the brake sensors he said they were not long enough. They are an aftermarket sensor that came with the pads. I measured them and one of them is approx 140cm and the other about 60cm.
I have written to supplier to see if I can swap them for a longer sensor if they have it so I will probably hear back from them on Monday.
I just wanted to know when I do get the correct sensor is it possible I can fit the sensors myself without removing the pads? For example can I take the wheel off and put them in or do the brake pads need to come out for them to go in?
Cheers
Nial