PZ60 Hydro Gear Purging using bypass valve

steger424

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My left side hydro pump surges in and out and seems to work normal after about 5 minutes. I decided to change the fluid, filter , and purge. I think i have the bypass valve located. See picture below. I loosen the bypass valve a few turns with the engine in full throttle. I work the steering forwards and backwards about 6 times with the wheels off the ground, and the wheels still move slightly but not much. I then shut off the mower and tighten the bypass valve and the right side works fine but the left side still doesnt seem to have all of the air out. Its not making any strange noises so i dont think the pump is bad, i just might not have the bypass valve located or opened enough? Can anyone shed some light if i am doing this right or any suggestions. Thanks in advance.
Pump is a Hydro Gear PR-2HCD-GJ1G-XXXX
pump.jpg
 

bertsmobile1

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Nice try but not quite right.
Run the engine at the lowest possible speed to purge hydros.
Running them full speed froths the oil so it is even harder to get the air out.
And don't be afraid to do it multiple times .
It is not uncommon for me to put a vacuum pump on an overflow line and still have to do 20 or more cycles to get all the air out.
 

steger424

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Do I have to open Boths pumps bypass at the same time, or just the one giving me the problem?
 

geelee

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only the one with the problem, I see you have the type with a fan. string, plastic bags etc get wrapped on the shaft at the seal for the charge pump and damage it. will suck air in but may not leak. it will never purge right. check that seal
 

steger424

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yes, i noticed it has been leaking on that side for some time. I was going to pressure wash all of the crud off and determine where the leak is coming from , then repair. It might be causing air to get in the system. thanks for the input.
 
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