Hydro-Gear 2800 Service Question .. Getting mixed info

[bertsmobile1]

The little pistons get air in then and in place of being pumped out so oil can replace the air, it simply compresses and decompressed.
This is why you purge with the wheels off the ground so there is no resistance in the motor pistons
You do it at low speeds to reduce the oil frothing
Some times they purge really easy and some times it takes forever and a day

Just make sure the region around the fill pot is VERY clean
do the final addition and go mow

 

[Tiger Small Engine]

The ZT 2800s have spin on filters. The fluid drains through the filter mounts.

Yep, good point. I forgot.

 

[MParr]

OK, after the purge & working it for a solid 1/2 hour. Been parked & now good & cold. Checked hydro fluid levels & both are slightly below the level on side fill level ports. Only like maybe 1/8" under...

So, should I top them off, then call it good.. I just want to be sure.

You want a slight trickle from the inside inspection/fill port. In other words, level with the bottom of the hole.

 

[7394]

Bert- I almost surgically cleaned my units.
MParr- 10-4 on that.

Ok, After 1st purge attempt, rear off the ground. Did that. Then put back down / level & left overnight.

Checked fluid levels next day & found to be low, took about 2 - 2.5 fl oz per side.

This 2nd time purging after adding top off oil previously mentioned, both units were lil weird noisy in free wheel mode (both sides, pump valves released) stroked 6 times slowly, shut off let sit 10 minutes, engaged the pumps valves & started it off the ground, it was quiet, still stroked the sticks 6 times slowly.

Then ran it a solid 1/2 hour all around the property, all seemed good, quiet & responsive.

Now fluid levels are a very slight bit low again. Temp overnight in my shop was 60* F. Just fyi.
Hot weather would likely read a bit higher. IDK to add just enough to hit bottom of side fill port ?

 

[7394]

OK, I can report my Liberty 48" is running so smooth, nimble & actually quieter than when I bought it new.

I only have 50 hours on my machine, but it was recommended by my Dealer to service these Hydro-gear 2800's early @ around 50-ish hours, to get off to a good start..

Because my Hydros have internal expansion tanks, it takes a bit less fluid (56.6 fl oz) each before purging) than external units.(Thanks MParr for latest current H/G link). So I went with Full synthetic 20w50 to help try & keep my hydros a bit cooler.

After final purging then overnight sitting, I ended up adding a few more drops of oil for a total of 59.6 fl oz in each unit to the bottom of side fill ports.

After that, is moving onto just everything else, where's my wax can ?