BX1500D leaks HST oil when hitch is raised

[oldnslo]

Blake
I presume your BX1500 is similar to the control style on the BX1850 I used to own. If yes holding the 3PH lever to raise brings the pressure up to relief pressure and keeps it there until you release the lever. This would explain why it leaks at that time but suspect would also potentially leak with a load on the 3 point arms.

good luck on finding the leak source and it being a simple inexpensive repair.

 

[BXAK]

Hello,

I blew everything off with an air compressor to get a better view of the area. When the 3PH lever is raised to max, oil leaks from behind the plate shown in the diagram. In my case there is a hydraulic valve installed where the plate goes. This valve controls a cylinder at the front of the trator for a snowblower.

I removed the valve and cleaned the area thoroughly. I then made a gasket from RTV silicone on the valve and let it dry. I installed it on the tractor and it no longer leaks.

I wish I could find documentation for the valve I added, but I can not determine whether it was supposed to have a gasket or not. I am using blower 2750D with quick hitch kit BX2711 and mid pto kit 2712.

Thank you kindly!

 

[oldnslo]

Blake
Were there any seals on the bottom of that valve? My educated guess is that cover connected pump flow to the 3PH control. If my guess is correct then replacing cover with directional control valve for the blower you now have two ports that will see full pressure when 3PH is in use and I doubt RTV will withstand that pressure very long before failing.

hopefully someone with knowledge of that cover and valve assembly will respond to either confirm my suspicion or explain what type of seal should be in that location.

 

[BXAK]

There were no seals or gaskets to be found. There is no groove for an o-ring either. The closest thing I can find to relevant information is this brush hog hydraulic kit for the BX series. The red line points to a valve that looks identical to the one I removed today. It shows 2 o-rings on the back of the valve, maybe they install on the mounting bolts?

We need to find the documentation for the BX series add on valve. I will keep looking.

Blake
Were there any seals on the bottom of that valve? My educated guess is that cover connected pump flow to the 3PH control. If my guess is correct then replacing cover with directional control valve for the blower you now have two ports that will see full pressure when 3PH is in use and I doubt RTV will withstand that pressure very long before failing.

hopefully someone with knowledge of that cover and valve assembly will respond to either confirm my suspicion or explain what type of seal should be in that location.

 

[BXAK]

I found the diagram for the LA181 loader that was available for the BX1500.

It shows two o-rings behinds the add-on valve. I will order those.

Thanks for all the help!

 

[oldnslo]

Blake,
I find it concerning that you did not see any grooves for the O-rings in the valve mounting surface. The seals must go around the ports - oil passages so some form of counterbore or groove is required.

 

[BXAK]

Blake,
I find it concerning that you did not see any grooves for the O-rings in the valve mounting surface. The seals must go around the ports - oil passages so some form of counterbore or groove is required.

Here is a photo of the adapter block. Looks it has recesses for the O-rings.

Thanks for your assistance Sir!

 

[oldnslo]

That picture certainly looks like it has recess for O-rings and would explain the leak if they are missing
Glad I was able to assist in diagnosis and appreciate you confirming diagnosis since this could help someone else in the future.

 

[BXAK]

That picture certainly looks like it has recess for O-rings and would explain the leak if they are missing
Glad I was able to assist in diagnosis and appreciate you confirming diagnosis since this could help someone else in the future.

In that spirit - the part numbers are
O-rings: 75538-68130
Hydraulic Adapter Valve: 75538-68112