Ser# KV0280B480358 Brakes will not release. Park Brake solenoid and Dash Switch were changed out by a different gentleman. Brakes still would not release. I tested the charge pump Pressure at the charge Pump Test Port ( Was M6 Port of the service description ) . It had 450PSI as was the specification with the oil warmed up and engine revved up. Checked the same test with a T-Tap on the line from the brake hose from the Hydrostatic Pump down to the Brake Pressure Regulator on the floor of the machine. Had 450 PSI with engine revved. Checked the pressure on the line from Brake pressure Regulator over to the steel line that feeds the brake Piston Ports on both traction motors...... Had 0 PSI coming to the brakes to release them. Suppose to be 300 to 340 PSI in manual. Any idea what could be wrong in this valve that would let nothing through. Anyone else ever changed one or repaired one of these valves that the John Deere Dealer said is Obsolete on 20 Year old machine. Valve is made by Sun Hydraulics in Florida Had # ECJ 0AM9-AA on it. Don't know if still available. Hoping mg 2361 is looking at site as he seems to know Deere stuff very well. Anyone else with input is welcome. Thanks in Advance Simon C Rocky Mountain House, Alberta
If you have pressure going into the regulator, and no pressure coming out, then there is excessive internal leakage. Yes, that assembly is obsolete so I can't help you with that. Did you take the valve out of it to check for blown O-ring's? It might be as simple as that. Then you can just match up O-ring's.
Found out the valve was made by Sun Hydraulics in Florida. Sent them a message with the numbers from it. Have a new one coming today from their Canadian supplier. It is in hard place to get out so owner is glad to have a new one. Wll let you know how it turns out. Thanks for your response, much appreciated. Simon C
Received the new valve today. Made by the same Sun Hydraulics. Funny that I can find the real thing and , obsolete from John Deeres point of view. They just want people to buy eveything new. This 20 year old machine only has 2300 hours. Might be able to get few more years out of it. Yes as you said mg2361 the seals could easily be changed out. but if i am short one seal at this place where the machine is I am in trouble. Was only $250 with freight and tax.. They previously bought the park break solenoid on the pump and it was $800 from Deere.. This was not bad for the fast service I received. Will let you know how it turns out. Thanks Simon C
Installed the new brake pressure reducing valve. Started the unit up and released the brakes with the dash switch. Moved forward and back couple feet each time with zero effort on the joy sticks. Unit was perfect , then the owner got in and he moved it couple feet and when he went to reverse the brakes locked on. could hear harshness coming from right side. Tested pressure with t-tap between line from pump to brake reducer valve. Had 450 PSI on gauge when revved up, but brakes would not release. Tested line from valve to steel brake line that releases the brakes with a T-Tap in line and had 0 PSI at idle. Turned up engine rpm and suddenly had 150 psi so thought need to adjust pressure relief valve in pressure reducing valve. Counter clockwise the allen head screw 1 turn and no change. Gave it an extra turn and still no change , in fact gauge never ever moved again. Even tried turning it in clockwise for 2 tuns from original position and no pressure change. Plugged the line that feeds the brake T in case oil is rushing past the brake piston seals, but still no pressure. Does the pump know if no oil is going to the brakes and suddenly the pressure becomes zero? Never saw anything in the old pressure reducing valve block or cartridge. Could the Hot oil shuttle be stuck, but even if it is the pressure should go to 300-340- PSI on the line feeding the brakes if the line is capped unless if the pump stops putting out. Or wondered if the priority valve could cause the Zero pressure problem. If the piston seals were done ( junk ) at each traction motor where would the by-passing oil go. Also i am told the 2 speed has not worked for a while, not sure yet why not. Any thoughts would be appreciated. Simon C
Motor case drain. 0 psi at idle with some pressure at fast idle indicates leakage somewhere.
Never thought to do case drain test before changing the pressure reducing valve. Suppose we could of ran a line from both case drains into a pail and released the brakes , then rev up engine to see how much leakage happened. Would of told us the state of the brake pistons on each side independantly. Could you put machine on solid traction and push against something immoveable to test the case drain line for traction motor leakage. Just wondering. Probably machine will be scrapped. Thanks for your advice. Simon C
You could, but there is no spec published by Deere for that. If you have enough leakage in your closed loop, then charge pressure would drop when machine is put under load.
Yes charge pump pressure will drop as I read on a manual when causing enough leakage with traction motors. This unit probably has multiple problems and very hard to fit T-Taps or pressure gauges into. Thanks for the advice. Simon C