L4200HST Oil filter bursts

[luebb]

Hello!
My L4200HST is killing HST oil filters. I use new oil and new filters. Could I be the HST relief valve? Where is it located? Do I have do drain the complete Oil before checking the valve? Could it be anything else?
Please help. I have the L4240HST service manual, but there are so many changes it doesn't really help at all.

 

[North Idaho Wolfman]

Start by reading the right WSM for the tractor.
Look at the envelope top right of the screen to help you out.

 

[85Hokie]

First question, what brand filter are you using?

 

[wdlanning]

Hello!
My L4200HST is killing HST oil filters. I use new oil and new filters. Could I be the HST relief valve? Where is it located? Do I have do drain the complete Oil before checking the valve? Could it be anything else?
Please help. I have the L4240HST service manual, but there are so many changes it doesn't really help at all.

Your vent is stopped up or plugged

 

[luebb]

Your vent is stopped up or plugged

Just to make sure that I didn't misunderstood: A plugged cooling cycle could be the reason for this problem?

 

[luebb]

First question, what brand filter are you using?

Only Kubota or Mann Filters. 2 original Kubota Filters bursted.

 

[whitetiger]

Check the Charge Pressure relief valve for sticking or debris restricting the fluid flow through it.
The" vent" would not affect it in any way.

 

[luebb]

Check the Charge Pressure relief valve for sticking or debris restricting the fluid flow through it.
The" vent" would not affect it in any way.

Alright. To check the relief valves I think I'll have to drain the complete hydraulic oil, right?

 

[wdlanning]

Check the Charge Pressure relief valve for sticking or debris restricting the fluid flow through it.
The" vent" would not affect it in any way.

If it’s over-pressurizing the filter is the weak link. Remove the filler cap and run it Probably won’t fail

 

[luebb]

Oh! One thing I forgot to say: The top speed I can reach is 17km/h instead of 25km/h. I think it could be related to the same issue.

 

[North Idaho Wolfman]

If it’s over-pressurizing the filter is the weak link. Remove the filler cap and run it Probably won’t fail

It's not a sump or case overpressure issue, it's a closed controlled pressure loop issue.
So the vent and the cap has no bearing on it.

 

[luebb]

I've found a book called "WSM Tractor mechanism" in german. Its not specific to my tractor, its for all Kubota tractors with all kinds of hydraulics, brakes, steerings, transmissions and so on. I've found an HST transmission in this book, which is absolutely similar to mine. With those drawings i've found the Charge Pressure relief valve and an extra relief valve for the filter, right next to the Charge Pressure relief valve.
I checked both of them. The Filter valve had a very very little dirt (maybe, not sure) and two shims - but the Charge Pressure relief valve had 10 shims and popped out of the thread due to the spring tension!!!

Maybe the preowner just wanted too much charge pressure? I reduced them to 5 shims to give it a try.

What do you think?

 

[North Idaho Wolfman]

I've found a book called "WSM Tractor mechanism" in german. Its not specific to my tractor, its for all Kubota tractors with all kinds of hydraulics, brakes, steerings, transmissions and so on. I've found an HST transmission in this book, which is absolutely similar to mine. With those drawings i've found the Charge Pressure relief valve and an extra relief valve for the filter, right next to the Charge Pressure relief valve.
I checked both of them. The Filter valve had a very very little dirt (maybe, not sure) and two shims - but the Charge Pressure relief valve had 10 shims and popped out of the thread due to the spring tension!!!

Maybe the preowner just wanted too much charge pressure? I reduced them to 5 shims to give it a try.

What do you think?

Sounds like your on the right path!

 

[luebb]

Sounds like your on the right path!

Good news!
I reduced the shims of the charge pressure relief valve from 10 to 5 - and the shims of the filter protection relief valve from 2 to zero. Works like a charm. And surprisingly I think I reduced the diesel consumption somehow close to half! Can't really imagine that by myself.

 

[North Idaho Wolfman]

Good news!
I reduced the shims of the charge pressure relief valve from 10 to 5 - and the shims of the filter protection relief valve from 2 to zero. Works like a charm. And surprisingly I think I reduced the diesel consumption somehow close to half! Can't really imagine that by myself.

Excellent job!