Cat 740b brake issue

Hi, I have a Cat 740b haul truck. I have just recently performed a 1000 hour service on the machine. All new filters and fluids. My operators are now complaining that the brakes will not hold them loaded on slopes and the brakes require much more effort then it had previously. After changing the hydraulic fluid it took a while for both the hoist/brake system and steering system to stop cavitating but after about 30 seconds everything seemed normal. After the complaint I bled the brake system...

Cat 740b brake issue

Cat 740b brake issue