ECSMechanic
Member
Anyone here that can help diagnose hydraulic pressure on a tms250b crane? I don’t have a lot of experience with crane hydraulics, but do have experience with hydraulic systems. Problem started out the operator needs to be at high rpm to get the swing to work. Checked pressures at the swing motor and found low pressure to the swing brake(less than 150psi). Checked pressure at the valve and also got low pressure. Less than 50psi. I checked pressure on the valve manifolds for the other functions, also reading low around 40psi. The weird part is all other functions work fine including the outriggers which I believe work off the same pump section. I checked gpm free flow of about 15 gpm. I also plumbed in a pressure gauge and was only getting 150psi. Would it lose that much pressure if there are bad seals in the swivel? I replace the seals in it about 7 years ago now and it worked fine until now. Owner bought a new pump but I would like more confirmation that’s the problem and not the swivel.