I have purchased a 1971 David Brown 990 with loader. The loader works good so I have reason to believe the hydraulic pump is working. However, the 3 point hitch will not raise/lower. I know I need to change the hydraulic fluid because it is milky. I have new shifter boots to install to keep water out in the future. So I have a few questions:
1. Need to know what position to have all the switches and knobs in for 3PH to work. Previous owner said he thought that might be all that was wrong with it. I've, tried every combination I know of with no success.
2. Assuming a valve is stuck in the valve chest, where is the chest located and how do I get into it?
3. Have heard of flushing the transmission sump with diesel fuel to clean things out. Good idea or bad?
4. Should I change the fluid/filter before attempting working in the valve chest?
Any suggestions about order in which to troubleshoot would be greatly appreciated.
1. Need to know what position to have all the switches and knobs in for 3PH to work. Previous owner said he thought that might be all that was wrong with it. I've, tried every combination I know of with no success.
2. Assuming a valve is stuck in the valve chest, where is the chest located and how do I get into it?
3. Have heard of flushing the transmission sump with diesel fuel to clean things out. Good idea or bad?
4. Should I change the fluid/filter before attempting working in the valve chest?
Any suggestions about order in which to troubleshoot would be greatly appreciated.