Hydrostat question

PaulS · #1 06-09-2013, 03:00 PM

When a part of the system such as the power steering unit and or the cylinder that actually pushes the steering is drained does that have to be filled before hooking it up or does that happen when you power up the system. How does the air get worked out of those parts.

J-Mech · #2 06-09-2013, 03:05 PM

No, they will fill themselves. Fill the trans up full, start the tractor. Then cycle the power steering full left to right until it feels as if it's working normal. Then refill the trans. The fluid has a tendency to have bubbles suspended in it after this process, and you may have to let it sit for an hour or so to let them out, but it will be fine. The only "problem" the air bubbles cause is they make the system whine until they are gone.

Maxwelhse · #3 06-09-2013, 10:34 PM

J, do you think jacking the rear of the tractor up would get the air out quicker through the axle vent? I've had decent success with this approach when filling automotive power steering systems (making the reservoir that much higher than the gear/rack).

J-Mech · #4 06-09-2013, 10:38 PM

Quote:

Originally Posted by Maxwelhse

J, do you think jacking the rear of the tractor up would get the air out quicker through the axle vent? I've had decent success with this approach when filling automotive power steering systems (making the reservoir that much higher than the gear/rack).

I don't think jacking it up would help any, however, you did bring up a good point! It is very similar to how a power steering system on a car acts after changing the rack and pinion. Leaving the "cap" off the system after running it to let it vent is a good idea.

Maxwelhse · #5 06-10-2013, 01:11 AM

Quote:

Originally Posted by J-Mech

I don't think jacking it up would help any, however, you did bring up a good point! It is very similar to how a power steering system on a car acts after changing the rack and pinion. Leaving the "cap" off the system after running it to let it vent is a good idea.

Excellent counter point and you're going exactly where I was thinking... A cub doesn't have a reservoir cap, just a vent in the rear housing. To be honest, the hydro's I've service haven't seemed to care one way or the other about it. I fill 'em and they work. I just wanted to ask the question to see what you thought.

Moving off topic (I hope the mods don't mind... Since it's good conversation and this is "General Talk"... Then again... The "smokers" have T-stats...)

I do the same thing when servicing the cooling system in cars, but backward. Leave the rad cap off and lift the front to make it that much higher than the thermostat.

Another trick grandpa taught me was to boil on the stove with a thermometer any new thermostat for 2 reasons.. 1, to make sure it would open at its specified temp, and 2 so you could stuff an aspirin in it to hold it open for expelling air upon initial fill-up.

Those wise old fellers sure do have some great tricks!

I hate to disappoint grandpa, but I used a Vick's cough drop on the last one I did since I was dead out of aspirin...

J-Mech · #6 06-10-2013, 02:10 AM

Quote:

Originally Posted by Maxwelhse

Another trick grandpa taught me was to boil on the stove with a thermometer any new thermostat for 2 reasons.. 1, to make sure it would open at its specified temp, and 2 so you could stuff an aspirin in it to hold it open for expelling air upon initial fill-up.

Most newer cars thermostat is on the lower return hose..... LOL. We just leave t-stat out all together as we fill. (If it's on top) Then put it on when the coolant gets to it. If it's located any where else, just pull a hose on the top, (like a heater hose). Note: some engines have air bleeders.

Note 2: Be careful of "grandpa's advice. Newer cars/ tractors/ etc, are made much different than that older stuff that grandpa worked on. Although in the right situation older ideas work and are good.... Sometimes "the way we used to do it" will get you in deep, DEEP $$$$ on newer machines.