Hi I have a 2010 C30 1.6 drive r-design I need to replace the front lower arms but cannot for the life of me find out if I need the 18mm balljoint or the 21mm can anyone help? I've even called Volvo but they couldn't tell me as they only use part numbers and the numbers they gave me don't match any of the parts I've seen! Thanks in advance

 

Are you replacing the entire arms or just the ball joints? , the ball joint sometimes fails as the rubber fails and dirt gets in , so for anyone reading this check the ball joint rubbers , easy to fix but if left then normally the entire arm needs replacing as the ball joint are riveted on (can be done but not easy)
If you give Volvo the vin Number they should tell you , different models have different sizes , what I found here in RSA , if I am doing the repair is to remove the faulty part and take it with me when getting a new one ,