Author	[Modern View]
david1 08-20-2012 13:32:02 184.5.149.118 Report to Moderator	My 2940 is making a noise that can be felt in the two metal lines on the right hand side that run from the pump back to the rear end. It does not make the noise at an idle . A friend said it may be the surge relief valve. Any body know about this ? Thanks [Reply]   [No Email]
Tx Jim 08-22-2012 03:35:26 67.142.163.26 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Walt In Jaxn Tn., 08-20-2012 13:32:02   buickanddeere said: (quoted from post at 19:09:48 08/21/12) Alright, take a poll of 50 people on the street of what "oil Hammer" is. Then ask another 50 people what "water hammer" is. If you think a poll of fifty(50) people on the street would confirm your explanation of water hammer and it correlation to a hyd system "YOU REALLY NEED TO GO MOOSE HUNTING" Besides no poll is required because TigerPaw4020 explained water hammer very well for you. :wink: This post was edited by Tx Jim at 03:58:11 08/22/12. [Reply]  [No Email]
Tx Jim 08-21-2012 15:40:13 67.142.163.26 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Willow12, 08-20-2012 13:32:02   Quoting Removed, click Modern View to see OK b&d explain the obvious analogy of water & oil? Yes both are liquids but water in oil isn't good. Please forgive me but I hadn't heard the term water hammer in conjunction with a hyd system until you used it. If I'm the only one that didn't know the definition of water hammer when it has to do with hyd's at least I know now. To me exclamation marks are very similar to capitalization such as WATER HAMMER but I see no analogy in exclamation marks [Reply]  [No Email]
buickanddeere 08-21-2012 16:09:48 216.183.151.133 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Tx Jim, 08-21-2012 15:40:13   Alright, take a poll of 50 people on the street of what "oil Hammer" is. Then ask another 50 people what "water hammer" is. [Reply]  [No Email]
TigerPaw4020 08-21-2012 14:53:23 74.229.102.150 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Willow12, 08-20-2012 13:32:02   No problem. If I could just remember the new stuff I learned, or even the old stuff I already knew, I could probably be dangerous. You mentioned cavitation, which is also a vapor pocket phenomenon. When the pressure in a fluid is reduced below the vapor pressure of that fluid at that temperature, then a vapor pocket forms. This is similar to the bubbles that form when water is boiled, but can happen at any temperature and pressure where the absolute pressure is reduced below the vapor pressure. In flowing systems the low pressure can be created in a specific area such as downstream of an obstruction or partially closed valve or just upstream of a pump on the suction side. As the fluid continues flowing to a higher pressure area, like through the pump where the pressure may go from negative to positive, the vapor pockets collapse. The collapsing vapor pockets are what we hear when we think of cavitation and can sound like popcorn or knocking. Both cavitation and waterhammer can be very destructive and should be avoided if at all possible. If they persist, expect to develop problems in the system whether hydraulic fluid systems, fuel systems, water systems, oil systems, or any other fluid system. [Reply]  [No Email]
Tx Jim 08-21-2012 14:29:58 67.142.163.27 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Joe Pro, 08-20-2012 13:32:02   TigerPaw4020 Thank you for your explanation. The only time when one can't learn something is when they're dead. [Reply]  [No Email]
TigerPaw4020 08-21-2012 14:23:29 74.229.102.150 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Dave H, 08-20-2012 13:32:02   Waterhammer is a flow and pressure phenomenon and can happen in any fluid. It occurs when a valve is closed too quickly in a pipeline on a flowing fluid. The fluid downstream of the closed valve continues to flow until it runs out of momentum. This causes a vapor pocket to form between the valve and the end of the fluid stream. After the fluid loses momentum and stops flowing forward, it then begins to flow backward pulled by the vapor pocket. When the vapor pocket collapses there is a large pressure spike and an associated hammer noise. The magnitude of the pressure spike and waterhammer is proportional to the energy in the fluid, velocity of the flow, and speed of closure of the valve. You may have heard it in old house plumbing when you turn off a faucet too quickly. Depending on the energy involved, waterhammer can be very destructive. It can burst pipes, destroy valves and fittings, and move things, including equiment. In large piping systems it can destroy pumps, valves and piping, and move pipelines, pumps, motors, and pipe anchors that may weigh in the tons by as much as several feet. [Reply]  [No Email]
Tx Jim 08-21-2012 12:31:28 67.142.163.25 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to larryanderson, 08-20-2012 13:32:02   Quoting Removed, click Modern View to see OK I'm fully aware of cracked/leaking tubes in JD utility tractors trans housings but what's the correlation to water?? I've always heard the problem was caused by cavitation not water. [Reply]  [No Email]
Tx Jim 08-21-2012 09:34:43 67.142.163.20 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to wendlingfarms, 08-20-2012 13:32:02   Quoting Removed, click Modern View to see Please define/explain "water hammer" as in all my JD experience I've never heard of it. [Reply]  [No Email]
buickanddeere 08-21-2012 14:45:18 216.183.151.133 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Tx Jim, 08-21-2012 09:34:43   I had "water hammer" in quotations and thought that would have made the term and the analogy obvious enough? [Reply]  [No Email]
buickanddeere 08-21-2012 12:10:42 184.151.63.183 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Tx Jim, 08-21-2012 09:34:43   What made the lines and fittings shake then break inside the transmission case? A plugged filter making the bypass valve and or the relief valve flutter [Reply]  [No Email]
buickanddeere 08-21-2012 06:32:14 184.151.63.183 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to david1, 08-20-2012 13:32:02   A loader or any other mods mounted on the tractor? Any rockshaft spray visible? Any heat and flow through the power steering when not turning? What is the transmission oil pressure and is it steady? Pressure is low enough that decent quality clear plastic line can be installed between the transmission and front pump inlet. And in the line between the front storage tank and the line back to the trans sump. Look for bubbles etc. flow testing from the trans to front pump should yield at least 6gpm. If the trans filter has ever been ignored long enough for the divert valve to operate. The "water hammer" can vibrate and break internal trans oil lines. [Reply]  [No Email]
Tx Jim 08-21-2012 04:09:41 67.142.163.23 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to Tx Jim, 08-20-2012 13:32:02   I thought of something else. Are the hyd oil line retainers(parts key #9) in place and clamped tight?? There should be 2 sets of retainers. This post was edited by Tx Jim at 04:11:18 08/21/12. [Reply]  [No Email]
MSM 08-20-2012 14:00:59 75.197.83.40 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to david1, 08-20-2012 13:32:02   I would be inclined to say you have a slight internal leak somewhere in the tractor(which they are known for). Just enough of a leak to stroke the main hydraulic pump slightly, but enough to give you the vibration/buzz noise. [Reply]  [No Email]
Tx Jim 08-20-2012 13:58:41 67.142.163.22 Report to Moderator	Re: Surge Relief Valve on JD2940 in reply to James Howell, 08-20-2012 13:32:02   Most hyd noises are caused by frt pump cavitation from running low on supply oil from trans pump. 2940 has a stroke control valve in frt hyd pump,a pressure control valve on RH side of trans case by hyd filter and a hyd filter relief valve but no true surge relief valve by that name that I'm aware of. [Reply]  [No Email]