Out using my machine the other day, and all of a sudden the turret would not swing in either direction, but you can hear and feel it loading down the engine. Next day I found a blow fuse, so I replaced the fuse and the swing worked again for about a second or two. I've had mice in it, so thinking I have a shorted wire in the cabin, I pulled everything apart, and repaired some chewed wires. I was then about to try it again with a new fuse, but when I checked, the replacement fuse did not blow, and is still good. The swing will not work, but still loads the engine. I am now guessing that maybe a solenoid went bad, shorted the first fuse, now went open circuit not blowing the second fuse? My problem is I'm chasing this without schematics, and I don't know where physically the auto swing solenoid is, and if there is a backup or emergency method to power it in case it's a controller logic issue ( I tried putting the controller in bypass mode but still the swing is locked) Anyone familiar with the auto swing brake layout of this machine, or an E120B should be similar and have any tips? Would be appreciated.
It sounds like the wire to the solenoid is broken. You can find the solenoid by following the small hose at the base of the swing motor back to the solenoid block.
I think I followed the correct hose, but not certain. I disconnected the solenoid plug closest to it to get an resistance reading but it was getting dark and the plug pins are in deep so i couldn’t get a definitive reading. There’s also two more adjacent solenoid plugs. I assume this is all a pilot block area. Ended up accomplishing nothing other than discovering I could disconnect all 3 of these solenoids, and all the excavator functions still work other than the auto swing lock is still locked. Maybe i’ll have better luck another day
I’m assuming the hose coming up in the middle bottom of the photo is the one you mean?
No, that is a return line on your rotary manifold. The brake hose will be somewhere on the swing unit directly behind that.
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It should be the small hose on the left side of the swing motor. If you followed that back to a solenoid block, then it is the one.
So this big guy is the swing unit? One of the 2 smaller hoses would be for the brake? Sorry for my stupid questions.
just saw your post john. so the leftmost hose?
One of the solenoids should be two speed travel. I don't recall what the other one does. Someone should be along shortly and let us know.
The left most hose. Yes
Ok Thanks. I’ll dig into it this weekend
So, I figured out , with you help: The solenoid connected to that small hose is the swing brake pilot circuit, and the closer one on the outermost side if the pilot manifold is the the track hi/lo speed. Where I confused myself: When I first troubleshot it I found a blown 10 amp fuse. Somewhere in the following days confusion, I had thought the replacement fuse went in the “controller “ position, which made sense with the old, old, old manual print I have showing the controller over watching the swing brake. But no. The swing brake solenoid is powered from the “parking “ fuse Which I mistakenly thought was always empty. Stupid old me. So I put in a new 10a fuse, swing worked for a second, and blew again. This time I put in a 15 amp fuse, put a current probe on the wire, and my swing is working but the brake solenoid is drawing 17 amps, so at least I can use it temporarily. I also found the “parking “ switch logic to be backwards to what I would have thought. When the switch is off, the brake release solenoid is always energized With the “parking “ switch on, the swing brake release solenoid is only energized for the moments I’m using the swing.
I can’t find an edit button for last nights post so this post is to correct my confusion on the confusing “parking” switch. I have it backwards in the previous post. With the switch “on” the Parking circuit is energized any time the engine is running, which energizes the swing brake solenoid, keeping the brake disabled. Normally you think of Parking as an applied brake, so to me it seems a bit logically backwards.
Anyone have any tips on how I change out the bad solenoid ( 1.8 ohms ), without all the hydraulic oil gushing out? I loosened the 4 screws and it started pushing out pretty good. Vacuum cleaner on the main tank, or something like that?
You should be able to just change the solenoid coil and not have to replace the whole valve.
That’s what I attempted. Maybe brand new valves don’t leak oil with the solenoid removed but this old one does.