Sluggish hydrostatic system

[Taylor123]

Hi all,

Let me start by saying I am fairly new to these forums, and to working on hydraulics,

I have a bobcat T136, which was built to be a dedicated trencher with a backhoe and blade on the front. Before I bought it, it has been converted to have a 3PT on the back and a forklift on the front. I use it at my cabin to move logs and slash piles around.

When I bought it the engine wouldn't start, simply because it was run dry. I bled the system and the Kubota V1702 is acting and sounding very healthy.

That being said the hydrostatic system does not seem to have a lot of power. Which I would expect it to have being that it was a trencher. It seems to labor quite a bit when I traveling, and labors even more when trying to use the steering or activating any other hydraulic cylinders when in motion. I have flushed the fluid and put in new filters.

Does anyone have any advice as to where I should start to look and what parts I should inspect to see if the system is operating properly?

Any advice would be very much appreciated!

Thanks

Taylor

 

[CJONE]

What labors? the engine? If so it sounds like the engine is weak or sized very close to max load. Why do you think the Hydros are weak? Do they do the job without stalling out? A pressure and flow test for the main system and flow test for the case drain is the only way to tell the condition of a Hydrostat without dissasembly. CJ

 

[Taylor123]

Hi there, and thanks for the reply!

-- What labors? the engine? If so it sounds like the engine is weak or sized very close to max load.

The engine is a four cylinder 35hp Kubota V1702, it hasn't had an issue and seems to be running like a champ. These are used in skidsteers and quite a few other machines, which you probably know, so I can't imagine I am pushing it to its max at 5mph..

-- Why do you think the Hydros are weak? Do they do the job without stalling out?

I think they are weak simply by comparison to other skidsteers and compact tractors I have driven. They do their job I suppose, I am starting to think it is just the hoses that are gunked up (which means there's gunk internally too) and not allowing for the proper flow. I say this because when a cylinder maxes, it puts a huge load on the engine, which makes me think the return lines must be clogged somehow.

-- A pressure and flow test for the main system and flow test for the case drain is the only way to tell the condition of a Hydrostat without dissasembly.

Well, I suppose that would be my last resort, I'm pretty far up in the hills and it was a pain to get the thing here so I hope I can work on it and solve it here.

Thanks again for the reply, I am still searching for the manual, if anyone knows where to get it that would be very much appreciated!

Taylor

 

[CJONE]

Hi there, and thanks for the reply!

-- What labors? the engine? If so it sounds like the engine is weak or sized very close to max load.

The engine is a four cylinder 35hp Kubota V1702, it hasn't had an issue and seems to be running like a champ. These are used in skidsteers and quite a few other machines, which you probably know, so I can't imagine I am pushing it to its max at 5mph..

-- Why do you think the Hydros are weak? Do they do the job without stalling out?

I think they are weak simply by comparison to other skidsteers and compact tractors I have driven. They do their job I suppose, I am starting to think it is just the hoses that are gunked up (which means there's gunk internally too) and not allowing for the proper flow. I say this because when a cylinder maxes, it puts a huge load on the engine, which makes me think the return lines must be clogged somehow.
***When you max a cylinder, you go to the relief. It will put a good load on the engine. Esp if it is not running to it's full potential.

-- A pressure and flow test for the main system and flow test for the case drain is the only way to tell the condition of a Hydrostat without dissasembly.

Well, I suppose that would be my last resort, I'm pretty far up in the hills and it was a pain to get the thing here so I hope I can work on it and solve it here.

Thanks again for the reply, I am still searching for the manual, if anyone knows where to get it that would be very much appreciated!

Taylor

Also be aware that your Hydrostat does not supply your Aux. hydraulics, it is a different pump. If you are traveling at max speed and you use your other functions you are placing a higher load on the engine. I have never seen hoses gunked up in a hydraulic system. Especially a hydrostat, the unit would fail from dirt long before the hoses got crud in them. CJ