OP
My Homemade Skid Steer Machines
- Thread starter justinlovestobuildstuff
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Vigo327
Platinum Member
Thanks for the follow up pics. Well, if pressure is feeding from left to right as viewed in that pic from operator station (i.e. first to drive motors, then to loader valves) then the power beyond fitting couldn't be leaking because deadheading a downstream loader valve would cause the upstream power beyond leak to 'bypass' a bunch of fluid back to tank rather than making enough pressure to stall the engine.
However, if i'm misunderstanding and pressure flows from right to left, then a leaking power beyond fitting absolutely could cause this. You should be able to redirect the tank port flow through a clear hose or just hold it slightly above the reservoir fill hole and observe tank flow when trying to operate the drive motors against a load. Maybe just chain the machine to a tree or something and see if tank flow goes up drastically when you load up the drive motors.
I keep feeling like i'm misunderstanding something about it but.. i'm fairly confident that any valves downstream of a power beyond fitting leaking to tank would not be able to make full pressure, while valves upstream of it would be unaffected by the leak. If this leak exists. But it does seem relevant, even likely.
However, if i'm misunderstanding and pressure flows from right to left, then a leaking power beyond fitting absolutely could cause this. You should be able to redirect the tank port flow through a clear hose or just hold it slightly above the reservoir fill hole and observe tank flow when trying to operate the drive motors against a load. Maybe just chain the machine to a tree or something and see if tank flow goes up drastically when you load up the drive motors.
I keep feeling like i'm misunderstanding something about it but.. i'm fairly confident that any valves downstream of a power beyond fitting leaking to tank would not be able to make full pressure, while valves upstream of it would be unaffected by the leak. If this leak exists. But it does seem relevant, even likely.
Last edited:
ning
Elite Member
ok just curious but
like should I be merely really impressed by your skills or should I change religions and worship your skills?
are we really talking degrees here
like should I be merely really impressed by your skills or should I change religions and worship your skills?
Vigo327
Platinum Member
I'm sure it's useful to somebody but i wish the percent system for slope didn't exist. 
Xfaxman
Super Star Member
- Joined
- Feb 8, 2013
- Messages
- 12,889
- Location
- Guthrie, OK
- Tractor
- Toolcat 5610 G - Bobcat V417 - TORO+Loader
Yep, I can directly measure degrees on a slope:I'm sure it's useful to somebody but i wish the percent system for slope didn't exist.
OP
justinlovestobuildstuff
New member
Vigo327
Platinum Member
Well, if you're thinking the pump is sucking air and looking to prevent that, the best shape for a hydraulic reservoir is tall and narrow. If you think about filling a straw up with liquid and hooking your pump to the bottom, how far do you have to tilt the straw to 'uncover' the pump inlet? 89.9 degrees from vertical!? This is one reason why loader towers make good fluid reservoirs. Tall and skinny. 
ponytug
Super Member
If you have foaming, you probably have an air leak somewhere. An air leak will absolutely degrade performance, as well as running the risk of cavitation damage to your pumps. I would double check all of your suction lines as a start.
How do you have your oil reservoir plumbed? Is the outlet to the pump at the bottom and the return below the oil level on the top? What is the total volume of oil in the system?
Do you have any oil coolers? Have you checked your oil temperature after some work? How is the oil color?
Finally while motor size is important, so is the pump/engine choice, and the setting on your pressure relief (trust but verify on the latter!).
Really creative jobs!
I have a slope rated tractor that does 30-35 degrees cross slope and a bit more up down, but traction rather than motor power or pressure relief tends to be the limiting factor, at least on my soils. (T18 Class)
All the best,
Peter
How do you have your oil reservoir plumbed? Is the outlet to the pump at the bottom and the return below the oil level on the top? What is the total volume of oil in the system?
Do you have any oil coolers? Have you checked your oil temperature after some work? How is the oil color?
Finally while motor size is important, so is the pump/engine choice, and the setting on your pressure relief (trust but verify on the latter!).
Really creative jobs!
I have a slope rated tractor that does 30-35 degrees cross slope and a bit more up down, but traction rather than motor power or pressure relief tends to be the limiting factor, at least on my soils. (T18 Class)
All the best,
Peter
OP
justinlovestobuildstuff
New member
The tank is quite small, maybe 3 gal, see attached photo. I used all 1/2" lines, and way oversized cylinders for the loads required so I feel like overall capacity is decent if you take all that volume into account? The return is on bottom and the suction is about 2" up from that. With cylinders fully extended the fluid level was very low, i think it was simply sucking in a little air when trying to crawl up hill. The Temps are fine and I have always just used trans fluid. I just welded up this extra tank which I will add to the rig. I will tee from both tanks for pump inlet/ returns and have some kind of balance line. Stay tuned, thank you
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ponytug
Super Member
Anything that you can do to keep air out of the suction line will greatly extend the lifetime of your system. If you can, try to have at least five or six inches of coverage on your outlet.
As a rough temperature check, after you run your machine for awhile, can you put your hand on the tank and keep it there?
All the best, Peter
As a rough temperature check, after you run your machine for awhile, can you put your hand on the tank and keep it there?
All the best, Peter
