Hi everyone! I'm a newbie to the forum and also to the Galion motor grader. The 118B that I just acquired is blowing the leaning control valve boot. The manual says that there maybe a kink/obstruction in the drain line from the hydraulic control manifold. The drain line looks OK back to the tank. I did notice that a flex line was installed just prior to the tank. If this flex line doesn't have the same ID as the OEM hard line could this be causing the problem? The front tires did seem to lean without input after traversing uneven ground. Could my problem be in the leaning cylinder or maybe even the control valve? Any and all information that could be shared with me will be greatly appreciated! I did look in the motor grader post but didn't find this specific issue. Thanks for your Time!
The line can look OK on the outside, and be collapsed on the inside. One test would be to tee in a pressure gauge at the valve block and see what kind of pressure the hose contains there. It's also possible that the cylinder is bypassing and overloading the valve or contributing some other way. Is this a one double acting cylinder? or two cylinders working together?
Delmer thanks for replying to my post! The cylinder is a double acting cylinder for the leaning function. I also have learned that I need to invest in more tools. The first to be a pressure gauge. I may replace the control valve manifold drain line to eliminate it. I was also thinking of removing the lean cylinder and locking out the lean function mechanically to see what happens. But back to your post PRESSURES, PRESSURES, PRESSURES will tell a lot!
Ok, I have purchased gauges but haven't put a manifold together yet to use them. I do believe that I have found the problem. There is a fitting installed in the manifold end cap. The manuals do not show a fitting in the end cap but they do show a fitting in the inlet cap for testing pressures. I think this fitting is restricting the lubricating oil return path through the end cap port to the tank allowing pressure to build. I'm going to run a drain tube from this port and T it into the manifold drain line and see if the boots stop swelling. Picture shows fitting in end cap right where the drain port is at.
Installed drain line. I have removed the fitting in the hydraulic manifold end cap and installed a drain line TEE'd into the factory drain line. I used a reducing connector that I drilled the orifice from a 3/16 to a 1/4 inch to help reduce back pressure. I then installed a 2501-L-06-04 elbow into the reducing connector. I replaced the hydraulic manifold drain connector with a 6804-06-08-06 TEE. I used a 3/8 inch hose to connect the new drain fittings together. The throttle quadrant needed to be moved to the right to accommodate the elbow and reducer combination. I have two hoses yet to hook up and then I can test to see if it eliminates the swelling of the hydraulic manifold control valve boots. It's raining heavily right now so i'll need to wait until the weather gets cleared up for the operational check. Below are pictures of the drain that I installed.
OK got the other lines hooked up after the thunderstorms past and did an operational check of the hydraulics. The boots puffed up a little but did not swell and burst like they had been doing. I think this is the right direction. I think I could drill the orifice in the reducing connector to 9/32". Anymore will probably compromise the integrity and it may snap off installing it back into the end cap. I also think I will replace the old aluminum line at the TEE with a 3/8" hose encase the inside of the aluminum line is collapsing as Delmer suggested as a possibility. Also as Delmer suggested I need to take pressure readings at both the hydraulic manifold control valve supply side and the drain side. I need to get some lines made for the pressure gauges and add another TEE into the drain side to attach a gauge. The hydraulic manifold control valve inlet assembly has a test port for the supply side gauge.
After the alterations to the drain that I made the boots continued swelling almost to the point of bursting after being operated for a short amount of time. So I decided to remove and inspect the other lines in the drain system. One is the steel line mounted to the bottom of the TEE that I installed at the bottom of the control valve manifold and the other is a flex line a previous owner installed under the cab floor going to the reservoir. The inside of the steel line looked OK but you can't see much. The inside of the flex line appeared very small and after cleaning the grime off the outside of the flex line, it's only a 1/4" line! The drain system hard lines from the factory were 3/8" lines if my research is correct. I replaced both the steel line and the 1/4" flex line with 1/2" flex line. I operated the grader almost four hours without any swelling of the control manifold boots. I believe the 1/4" flex line was the culprit! It wasn't able to carry the volume of fluid needed back to the reservoir. I'm a dry and happy Galion operator now. :tong I still do need to listen to Delmer and put hoses on my pressure gauges so I can take readings in the future. I'm sure I'll need them!!