aloha
Silver Member
- Joined
- Dec 3, 2003
- Messages
- 215
- Location
- Hawaii - Big Island
- Tractor
- Kubota B7800 / Kubota RTV X900 / Scag Turf Tiger
My Woods BH7500 backhoe developed a leak in one of the port relief valves. So I replaced the valve. To get access to the valve required temporarily removing several of the hydraulic hoses.
The first time I tried to use the BH after replacing the valve, the boom would not pivot to the left (as viewed from the rear-facing position). I could push the boom to the left, with effort, when the control handle was moved to the left-pivot position. Movements all other directions appeared to be correct and at the force normally expected.
The hydraulics are fed off the tractor, a Kubota B7800.
After working the tractor for a couple hours with the BH mounted the BH would weakly pivot to the left, stopping about 45 degrees to the left of centerline. The force was little enough that I could prevent the swing by grabbing the boom with one hand while the control handle was in the left-pivot position.
I assume that my problem relates to the replacement of the port relief valve, and either I have air in the hydraulic system or the new valve is defective. I welcome any comments or alternative suggestions.
If the problem was due to air in the lines, I would have expected the air to have worked out of the system during the time the tractor was running and through exercising the BH functions that were operating normally. The BH manual makes no mention of bleeding the hydraulic lines after replacing the valve.
Any suggestions? Since it has gone from no movement to the left to moving weakly to the left, is my best bet just to keep the BH mounted whenever possible while the tractor is being used for something else, and hope that over time it regains full function? Is there a secret method for bleeding the lines? Is there any way to test the port relief valve without specialized tools?
Thanks.
The first time I tried to use the BH after replacing the valve, the boom would not pivot to the left (as viewed from the rear-facing position). I could push the boom to the left, with effort, when the control handle was moved to the left-pivot position. Movements all other directions appeared to be correct and at the force normally expected.
The hydraulics are fed off the tractor, a Kubota B7800.
After working the tractor for a couple hours with the BH mounted the BH would weakly pivot to the left, stopping about 45 degrees to the left of centerline. The force was little enough that I could prevent the swing by grabbing the boom with one hand while the control handle was in the left-pivot position.
I assume that my problem relates to the replacement of the port relief valve, and either I have air in the hydraulic system or the new valve is defective. I welcome any comments or alternative suggestions.
If the problem was due to air in the lines, I would have expected the air to have worked out of the system during the time the tractor was running and through exercising the BH functions that were operating normally. The BH manual makes no mention of bleeding the hydraulic lines after replacing the valve.
Any suggestions? Since it has gone from no movement to the left to moving weakly to the left, is my best bet just to keep the BH mounted whenever possible while the tractor is being used for something else, and hope that over time it regains full function? Is there a secret method for bleeding the lines? Is there any way to test the port relief valve without specialized tools?
Thanks.