Parts Unlimited sales a rebuild kit for the 300 the part# is 1702-0002 you will need one for each side.You need to take it apart and look at the wheel cylinder but most of the time they can be rebuilt.We orderd some of those last summer and they were available you might want to check with another dealer to make sure just in case someone looked at the wrong number its worth a shot.They sold Thousands of those models,I can't beleive that they discontinued that part already.If you would like call this number 1-800-356-1354 and tell them colescycle told you to check with mike he knows everything Honda and what fits what.Good Day