The bucket and tilt both will not hold load. It's a slow leak , but if I raise the bucket in the air in the evening. The next morning both are down to the ground. Even with the safety bar up in the air/enabled. Is there a step by step procedure for this? Is replacement of the whole valve assembly common? Or are these repairable?
Yes, you can repair/rebuild them. There are many videos on youtube showing how it is done. You will need seal kits which should be available from Bobcat or aftermarket.