Thread: Hydraulic oil foaming in a pressbrake

Got the foaming problem sorted after much frustration.
Drained the oil, cleaned the tank, replaced all the screens and filter, then installed new oil.
Ran the machine and the foaming was ten times worse.
I finally traced the problem to a seal in the top of the pump. The pump is submerged in the oil, so I thought, however there is a bell housing that the pump is bolted to that submerges it and the input seal is on the motor side of the housing and is therefore able to suck air. My cleaning up the area removed all of the old oil and grease. This must have been helping seal the pump.
The shaft was fairly heavily scored so I ground it down and fitted a new seal. Fixed.
As far as the cylinder cap wear goes the solution turned out to be simple. I acquired a Waldown toolpost grinder and ground them out to the required size, then the guys at the chrome shop built up the shafts .008 oversize.