Hello! I’m helping a friend with his 2008 Yanmar SV100. The turn motor doesn’t work when it’s cold. I can hear fluid bypassing when the stick is moved back and forth. If it’s throttled up it turns to the left a little. Here’s where it gets weird, if you move the travel sticks even a little the turn starts working. I don’t have a schematic for this machine so I’m not sure what they have in common. The other weird thing is when the turn motor starts working the right track motor loses power, Won’t track straight. Machine has 5500 hours, newer fluid, serviced regularly.
Good day Attached may help, more on the website free to download when required. Kind regards Uffex
Thanks! I’ll check
Good day If you could post a shot of the motor & label may be able to give better help. Kind regards Uffex
Thanks! I’ll check
I read through the ExaTech site and have a few ideas. What I just can’t seem to find is the correlation between the slew/turn and the travel systems. I’m thinking it’s important for troubleshooting. Anybody know??
Good day JC If you have a hydraulic schematic to post, we may be able to answer your question. Kind regards Uffex
I would think that the swing and and the left travel motor must be on the same pump
I wish I had a hydraulic schematic. Doesn’t appear to be any online.
Good day Next best is a few snaps of the installtion -MCV- & labels, may be able to identfy those parts. Dont give in think crossways. Kind regards Uffex
Good day If my information is correct the spools are manually controlled, I suggest have a look if they are working correctly. Kind regards Uffex
Hey there! I finally got the picture of the turn motor.
I got to play with the controls today. So here’s what I observed. Started it up cold & turn is totally locked up. I move the travel sticks forward and back fast as I hold the left turn and hear a creaking noise and then it starts moving. I had to do this a couple times to get it to stay moving. Sounds like a drum brake when it’s been sitting a long time and breaks free. Somehow the turn motor brake isn’t releasing. It’s a bitch to get to because he has an auxiliary cooling system mounted over it.
Good day JC Information as best I have may help out. Kind regards Uffex
Good day JC It cost ten dollars see attched. Kind regards Uffex
Hello Uffex, what’s $10? I looked at the attached file. Is there a key? To show what the abbreviations are. I still don’t understand what the correlation between the turn and drive motors is. I don’t see anything in that schematic that shows them interacting. Thanks!
Good day JC Sorry there is no key with this schematic, so I may help out, do you mean when you conta rotate the tracks to turn the machine, I have attached some information so we are of the same understanding. Kind regards Uffex
Hello, No not conta rotating just forward and backward on either stick causes the rotation to work slowly at first then it frees up and continues to work. If it does lock up again just light pressure on either stick frees up the turn motor. I just don’t understand why. I was just trying to follow the schematic circuit for the turn motor. There’s a lot of abbreviations. I’m not an expert but the only thing I see the turn circuits and the Drive/crawler have in common is the solenoid valve and the swivel joint. I’m pretty good at troubleshooting problems but I don’t think I have a good understanding on how this system works. As I understand the pilot pressure is a constant pressure to all circuits to keep the valves from bleeding pressure. Servo pressure is the high pressure to the valves that control operation. Right? Which is which in the schematic? Pilot is the dashed line’s right?
Good day JC Servo pressure comes from a small pump and has a fixed pressure, normally about 30 bars (430p.s.i) pilot pressure comes from the controls this will be between 0>servo pressure according to lever or pedal movement. Main pressure is from the main pump lines and should be regarded as high pressure. If you are using small lever movements, it can depend on how much pressure is required to shift the valve spool. Once the valve is shifted, it must release the travel brake see attached. It may be appropriate to be sure you have selected low speed for slow crawler movement. Hope it is of help Kind regards Uffex
Update: My friend finally found a mechanic that figured out the problem. Only took 3 shops and several mobile mechanics to get here. He said; “Well the mechanic figured it out ,that guy is pretty good ,there was a little screen from the main valve body under the cab to the swing motor and there was a filter that screws into the line that was plugged he said now it works fine and he says that there's something bleeding by on the swing motor for my drive motors so I just have low range now so everything's working he said he has to get it put back together now” I didn’t see or hear anything about that filter online. Just FYI for anyone else who has this issue. Thanks again for all your help!!
Good day Thank you for the update, the support we give relys on information and your resposnse is helpful. As I understand your post you are describing a in line filter which is absent from the schematic. Kind regards Uffex
Jc269 is there anyway you could elaborate more on where this inline filter/screen is? I have a very similar problem and I'm hoping my repair will be the same.