Join Date: Mar 2015
Thanked 23 Times in 22 Posts
Yes they are repairable.
If you have the full parts break down you will see the round block thet the pistons move in and the plate with slots that controls the oil flow.
When you hear growling it is because the oil is squeezing out between the two rather than going into the pistons.
The pump & the motor are very similar, they both work the same way.
These units are made in a sterile dust free factory so they can not be clean enough.
When I do one I remove the unit, degrease it pressure wash it, soda blast it then pressure wash again before I start to pull it apart.
It gets worked on sitting on a damp towel & is covered with a damp towel every second that my hairy gloved mitts are not inside it.