Hello Everyone, With all of your help a few weeks ago I was able to replace the seals in swing gear assembly, swing motor, travel planetary seals. At that time I also had an issue with the swing brake coming on intermittently. I wasnt able to find the source of that problem but I was also directed to the swing brake bypass switch ( on this forum as well) under the storage tray of the machine. So all was well for the last week or so. I took the machine to my island project. We cleared the lot, dug out the stumps and this afternoon the starter acted up. I was able to get it going with a tap and someone holding the key in the start position. I will see if i can find a starter tomorrow. But then immediately after the machine stopped mid swing rather suddenly. I had just taken my first scoop of dirt for the excavation. It was stuck and wouldn't move. After my last issues I am familiar with the two small hoses that go into the swing motor that are part of the swing brake. Last time I was able to see that they were twitching every time the machine stopped. Until today the bypass switch was working just fine. And I could manually flick the swing brake switch still if I wanted to. Immediately after this happened I could here , what I assume to be the swing brake solenoid?, clicking very rapidly and the hoses twitching rapidly as well. This eventually stopped and the machine is now stuck sideways. If I try to swing the engine bears down slightly like it is trying to swing but cant. I am really in a pickle here. Being stuck on an island with the machine sideways that I cant get it down the path to even be loaded out of here. Does anyone have any ideas what this could be? Is it possible to eliminate the swing brake entirely? Just throwing ideas around. I think that hydraulic pressure releases the swing brake? Bypass the solenoid and have pressure to the swing brake all the time so it stays off? As always any help is greatly appreciated.
Hello Everyone, So I have been doing some reading on this forum and calling the komatsu dealer for parts pricing in case. $ 1400 for the swing solenoid and $ 2200 for a starter...yikes. I will look into some rebuilders for the starter and see about aftermarket if I need a solenoid. Maybe someone can help me with some tourble shooting. - Iwas going to pull the plug off the solenoid and see if its getting power to the plug. Should be 24 volts correct? - Once I pull the plug off should I test the ends going into the solenoid? What should the resistance be? - Can someone explain how to remove the solenoid? I have never taken one out. Looks to be a plastic wheel on the back side that I can see , I was thinking about pulling it out and taking to hydraulic shop to see if they can match it. If anyone has any other ideas I would welcome any help.
Hi, first off bypassing your valve is not highly recommended,. Question, do you have a pic of your valve, would help out a lot, I don't have a manual for that maschine
Hi, Thank you for the reply. I will take a picture of it tomorrow. It is raining today and will go back to the island tomorrow. I have the manual for the machine. I might be able to figure out how to post info to you if you tell me what you are looking for? Do you know what the resistance on the coil should be when I test it?
I would be checking battery/system voltage first. I'm assuming this is a 24v system. You will need proper voltage to run those solenoids. Hook up a good voltage meter and monitor it while moving the machine about to see if you have a variance. I've had to replace my starter solenoid on my PC200lc6 several times. Pretty simple installation with 2 bolts to be removed and a few wires. You can now find these aftermarket on Ebay or Aliexpress and save a bunch of money. The contact plate or contactors get pitted and then it works intermittently before finally dying permanently. The clicking of the solenoids lends me to believe you may have low voltage or poor connections somewhere along the way to the solenoids. There is likely also a master relay located near the batteries that could be going bad and not allowing full voltage to the system when the key is in the on position. Check on that master to see if it is providing consistent current and voltage.
Hi Tree Muncher, Thank you for that. I am going back tomorrow with tools and a good multimeter. I ordered an aftermarket starter just to get it going again. I will check for proper voltage as well. Yes it is 24 volt. The swing brake is the real issue. Stuck sideways with zero movement. I assume these use voltage to apply pressure to the swing brake to release it correct? So if there is no voltage to the solenoid then that would freeze the swing brake? For the last week I have been runnign with the swing brake bypass switch on ( you directed me to that) and it was working great and I could still apply the swing brake with the console switch if I wanted too. This just happened all of a sudden. No warning. Just stopped swining. before it was an intermittant problem.
Resistance I am not 100 percent sure, does your maschine have a swing lock on switch on it? If you had a manual with schematics It would be helpful
Yes it has the swing lock switch and the swing lock bypass. Right now neither switch have any affect on the condition.I unplugged and replugged the solenoid but nothing either. Being on the island I didnt have any tools . Tomorrow morning I am going back with tools and multimeter. I will see if there is power to solenoid first I think. If there is. Then I will check the resistance on the solenoid. I will work on finding out what it should be.
Do the solenoids just pop out after unscrewing the plastic nut on the back?
You should have to unscrew it out, it is seated with a oring
I was reading your post again, I missed it when you said the hoses were twitching, so more than likely either the low voltage, or your solenoid is bad, with there being a lot of heat and your magnet is constantly powering on/off, I assume the solenoid itself is bad.
Ok. I will be checking tomorrow. I called the dealer and they said $ 1400.00 for one.....Thats a crazy price for a little tiny part. So far no luck in finding aftermarket.
It might sound funny, but check out amazon
Not funny at all!. I did that but nothing that I could find . Or even ebay. I think the covid thing has really taken alot of stuff off those sites to free up space. I have been hammering away online most of the day but nothing yet.
They have one for a pc60, $222.
what?!! Let me look again.
Pc60-5 sorry
Put in magnet solenoid
Swing brake solenoid for your search
I dont have anything coming up. I am not sure if I am doing something wrong in the searching.
Wait I try to send the link what's your email
Put in search GOWE swing magnet
Artikel number GWE-1005428
Ok. Now I see that one. It looks very close but shows the wrong part number. Let me ask the seller if they have the right part number. Thank you very much!
No problem
I just had a thought. I was going through my parts manual a realized it lists 4 solenoids in that bank all the same. Is it possible to switch one out with the swing brake one if the swing brake solenoid is bad? One was listed as the travel speed solenoid. I have never switched this machine to high speed. If I switched the two out would that just leave the machine in low speed and move that solenoid to the swing brake? Any chance of damage if I did that? If it worked I could finish the dig. Barge the machine out and by then the new solenoid would be in ( 1 week to order)
All four solenoids are the same and switching them is usually the easiest way to test the problem. The big money given to you is for a whole valve which is never necessary. The only thing that goes bad is the coil. The coil is replaceable with any coil that has the right inside diameter and depth. You can change harness connector to regular spade connectors if necessary. The coil should show somewhere over 7 ohm of resistance. What you don't want to see is infinite resistance or one of the connectors shorted to the case. The problem can also be in the supply circuit to the solenoid. If the solenoid checks good then check for voltage at the wiring side of the harness connector. It would probably be a good idea to carry a meter and some tools with you any time you run the machine.
Not sure if John assumed a 24V coil, but I'd stick with 24V and a coil that "looks close". But check the voltage UNDER LOAD first, that is, rig up some test connectors so you can try the swing and see what the voltage shows at the coil, with the coil in the circuit. I suppose it's easier to test the coils continuity, ohms, shorting to case first, but then test the voltage before switching stuff around and making more trouble. In general, the golden rule of working on old electronic issues, "CHECK THE GROUNDS!".
Sometimes a bad ground can cause havoc on your solenoid switches. I would check all known grounds and run a new heavy gage ground to the solenoids just to rule that out. Sometimes our crane switching solenoids will work intermittently and or unreliable. More often than not it is a poor ground and or a low voltage power source. What island are you working on? Just curious. Best of luck!
Good morning Guys, That you very much for all the excellent information and ideas. i am going to pack up some tools this morning and head over do some testing. I will try to rule out the electrical side of it first. A question on switching the swing brake solenoid and the travel speed solenoid. If the swing brake one is bad will it do anything to the travel speed if installed there or will I just be in slow speed travel?
If the coil is shorted to ground, or significantly lower resistance than the others, then don't bother hooking it up for the other solenoid. If it's an open circuit/ no continuity, then it won't matter. Don't hook voltage to a coil that is not attached to the solenoid, they need the core for extra resistance, ohm meter only if the coil is off the solenoid core. IF your suspect coil works on the other function, and the other coil does the same thing on the swing solenoid, go back to the electrical supply to that coil.
Hi Delmer, Thank you. I am not really sure how the solenoid and coil are attached. I have never had one out yet. Do I just unscrew the plastic nut on and and take the entire unit out? Solenoid and coil together? I am just not sure if I am swapping the entire solenoid or just the coil part? If the swing solenoid test bad can I install it in the travel motor location and then not hook the wire up to it? Just to fill that hole. And then install the travel motor solenoid in the swing brake location?
One consideration that will cook a solenoid faster than any is loose connections, repeated on/off signatures start beating the coils down with heat of initial amps loading. Some solenoids also use a two part winding a Pull in that switches to a Hold in winding once fully engaged. If this type are sensitive to throw distance of the moved pin linkage or piston, will be a button inside the solenoid that has to be depressed when fully engaged to stop the Pull in winding current flow, a shorted or open Hold winding will cause the same rapid on/off cycling and overheat the solenoid.
You will be in low speed, the solenoid is only for high speed range
Would it be safter to leave the electrical connector unplugged on the high speed travel solenoid if I swap it with the swing solenoid? Providing the swing solenoid tests bad
Yes, you should be fine leaving the connector off. Nearly every solenoid valve I've seen the coil comes off the valve. That seems to be what John was saying also. You shouldn't have to get into the oil to do this, at this point. It should be all dry.
That's what I would do. High speed travel is an option via a switch and not necessary for operations. Just use the bad solenoid valve to block the hole that a known good one has come out of if you have to change a valve stem. Any unplugged solenoid should cause no issue with the system for diagnostics but be sure to mark your wiring so that you can get everything back to factory connections. Play musical solenoids for diagnostic purposes but make sure you know which ones have gone bad. If these are the same part numbers as used on the PC200 series machines, they should be easy and cheap to locate via aftermarket suppliers. Rarely, the valve that the solenoid sits over can get dirty and cause issues but most often, it is electrical problems causing the issues.
Good Afternoon Guys, So I have an update. I installed a new aftermarket start first thing. That seems to work well and was 400 as compared to $ 2400 the dealer wanted for new ( is that even possible?) Then I went on to the solenoids. They all had 26 volts going to them. But no resistance to the swing coil. The others tests about 60 ohms. The manual specs between 50 and 100. Despite the parts manual saying the solenoids are the same they are clearly not when I pulled a few off. The swing coil is much larger length. I pulled off the swing solenoid coil and found the issue. See the picture attached. The wire was touching a hydraulic hose and rubbed through. Fortunately I brought my soldering kit and was able to solder the stub on to the wire again. Some shrink wrap and lots of tape was the best I could do. The yellow coil is the swing brake coil. The black one is the travel speed coil. It seemed to work and I ran it for 4 hours after. I am hoping I can find a replacement coil to have on hand. I wanted to thank all of you again. I could not have done it without you. Your knowledge is impressive. And very generous to take the time to help
Go to these people, I just typed in a generic search for yuken solenoids and got here: http://www.houstonhydraulic.com/default.cfm
I always have a MAP gas torch on my truck. I keep several soldering tips with electronic solder wrapped around them in a few places on the truck in case I forget to reload one. Vise grips hold the soldering tip while the torch heats it enough to hold heat for these electrical soldering jobs in the field. Sort of Red-Neck Soldering, but I have saved the day at work and on motorcycle trips with these handy kits. Your solenoid repair will likely hold as long as the machine. Once you replace it, keep it in stock in case you need a spare. Nearly the exact same thing happened on one of my machines with an air reversing solenoid - wires pulled off the solenoid. Chipped the plastic down to expose enough wire, did the Red-Neck soldering station routine and went back to work. Still working until I put the new $150 part on. Glad to see you got the issue diagnosed and fixed. I'm sure it was a huge sigh of relief to find a fairly simple fix that you could handle yourself without calling in a factory tech.
It's like the YouTube creator I watch says, 'it's only temporary unless it works!' Watch Wes Work. Nicely done glad you solved the problem without throwing a bunch of money at it
Yes, Thank you Tree Muncher. I hope it works for awhile. I still havnt had any luck finding a replacement. I keep getting the answer that these coils are propitiatory to komatsu and yuken cant make them. I did find an offshore company ( Fridayparts) that says they have aftermarket replacements for around $ 125 canadian shipped. I may roll the dice and see how they look.
I used to get them from Spenser Aircraft. There is now a place called Spenser hydraulics that might be a source.