Check to see if their is gas in the system. the compressor will not come on if their is no gas in the system. this is to prevent damage to the compressor
You have an alarm/Immobilizer/Kill switch? Sometimes they may need servicing.
Also you could check an electrician. The starter might not be getting enough current to start properly
You should change the rubber. The rubber helps to prevent dirt or water from getting unto the piston which could lead to rusting. Eventually the caliper will start to stick and might not be able to retract properly
