Justintime Posted September 15 Share Posted September 15 When would should I be using the Dump Valve pedal? I looked in the service manual, no idea though when to use it. Quote Link to comment Share on other sites More sharing options...
Binderdan Posted September 15 Share Posted September 15 In regards to what type of machine? What type of transmission? The dump valve on my backhoe with a torque converter transmission relieves hydraulic load on the engine for easier starting especially in the cold, and can act sorta like a clutch to disconnect drive pressure but in a non mechanical way. The dump valve on my hydrostatic skip loader also unloads the hydraulic load on the engine for easier starting especially in the cold, but can also act as a Foot-N-Inch valve. According to the manuals you are supposed to always depress them for starting so the machine wont move unexpectedly. I have never used mine for starting, but I live in a warm climate. I believe there are other applications that have a dump valve but that's all that come to mind. 1 Quote Link to comment Share on other sites More sharing options...
Justintime Posted September 16 Author Share Posted September 16 Very helpful thank you. This is for an ford 555b backhoe. I'd assume the same use as what you described. I will give it a shot and see if it is different when starting. Thank you again Quote Link to comment Share on other sites More sharing options...
Binderoid Posted September 22 Share Posted September 22 On 9/16/2023 at 2:04 PM, Justintime said: Very helpful thank you. This is for an ford 555b backhoe. I'd assume the same use as what you described. I will give it a shot and see if it is different when starting. Thank you again If your B has a torque converter, it is used for loader operation when loading trucks. There is a red button on the loader control lever that serves the same purpose. The function disconnects the transmission so the boom can be raised without forward motion if you are too close to the truck. It will not aid starting in the least. The loader pump moves way more oil than the converter pump… you can’t disconnect that at all. The dump valve only releases oil from the directional clutches… the pump is pressurizing the converter at all times, which means operating the valve will have no effect at cranking speed. 1 Quote Link to comment Share on other sites More sharing options...
Justintime Posted September 22 Author Share Posted September 22 2 hours ago, Binderoid said: If your B has a torque converter, it is used for loader operation when loading trucks. There is a red button on the loader control lever that serves the same purpose. The function disconnects the transmission so the boom can be raised without forward motion if you are too close to the truck. It will not aid starting in the least. The loader pump moves way more oil than the converter pump… you can’t disconnect that at all. The dump valve only releases oil from the directional clutches… the pump is pressurizing the converter at all times, which means operating the valve will have no effect at cranking speed. Thank you for this. I do have a red button kn the handle I will play with it a bit Quote Link to comment Share on other sites More sharing options...
Binderoid Posted September 22 Share Posted September 22 26 minutes ago, Justintime said: Thank you for this. I do have a red button kn the handle I will play with it a bit It may not work. If you don’t have a cab they got weatherbeaten and cease to function. The micro-switch under the floor is much better protected. But… there is a lot of dirt down there… sometimes you step on the button and the tractor will never move again; the mechanical part of the switch is dirty and stiff. Let the button snap back up a couple times and that may shake it loose. The final cure is lift the floorboard and clean it up and lubricate it. Quote Link to comment Share on other sites More sharing options...
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