hi .........being a ex-stannah stairlift engineer i have never come across replacing bearing on the pinion drive/motor? replaced the motor/gearbox quite a few times though........anyway if the stairlift has been off the rail for any lenght of time,that means the main carriage batteries have not been getting a charge...put the stairlift on a charge point for 24hrs and then test the 2 x 12v batteries individualy in the carriage if either of them fall below 11volts they probably need replacing[most stairlift batteries only last between 3-5 years]also you said the stairlift seems faster coming down,if you got a clamp meter,clamp the blue and brown motor wires next to the main pcb in carriage to see what amps the motor is pulling it should start of upto 16 amps then drop down to 5 to 7 amps in both directions, regards
IAN.....PORTSMOUTH/UK, April 2011