So, I was working the machine digging some stumps up and after about 30-45 min of working it hard, the wifey saw some smoke coming from the cover over the weights. I shut it down and looked around the machine to see what got hot. After confirming no fire I started the machine back up and 0 hydraulics work. I checked fuses and looked for something that maybe have been burned. I really need a place to start looking. Everything was working fine up until that point.
Check coupling between engine and pump
Second that. If you want details, illustrations, etc, please provide a machine Serial Number.
Thanks for all the replies. The serial number for the machine is CAT3027DELJ700627
The attachment shows the pump mounting and the engine/pump coupling.
Thanks for the info, got the weights off, without any problems. Waiting on some rubber stoppers and caps to arrive. So if I'm reading the the diagram correctly the number 3 position bolt is what drives the pump?
No, callout #1 should be the coupler. The bolts connect it to the flywheel.
There is a Page 2 of the attachment with piece part names and numbers.
Couple more questions. When I take off the big return line off the bottom of the pump is all the hydraulic oil going to come out? Also what would have caused the coupling to fail? Just worn or something I may have done? Just wondering.
That big line is likely pump supply, not return and yes, your reservoir will completely empty in about 3 seconds flat if you remove it. You'll have to drain the reservoir first. Couplings will wear out over time or a seized up pump can strip it out. Over pressured hydraulic system (like a relief turned up over spec) can cause extra resistance and take out a worn coupler too. In all honesty I would run some pressure checks and find out if the pump is moving fluid first before yanking the pump. Could be something dead simple like the pilot lockout malfunctioning.
Unless that smoke was from an electrical wiring issue (that ought to be easy enough to spot) then a burned-up coupling is probably the next item on the list of probabilities.
Ok sorry if this is a dumb question. I really am a mechanic by trade, just not on this type of equipment. Where is the hydraulic fluid drain plug? There is a pipe with a brass cap on it and what looks to be a helicoil inside of it that leads to the tank. I'm not sure that this is what I'm looking for. I really know this is a thick question.
The only thick/dumb question is the one you don't ask IMHO.... See attached for the hydraulic oil change procedure. It looks to me as though the tank has what's known in the trade as an "ecology" drain. There is a spring loaded check valve inside the drain tube that has to be pushed upwards, usually by screwing a short length of pipe of the appropriate thread (Ref #31 on the 2nd attachment), in order to lift the valve off the seat to allow the oil to drain out. If you don't have one an investment in an Operation & Maintenance Manual might be a good idea. The Cat Publication reference for your Serial Number is SEBU8745 and you can download a copy for $52 from the Cat Pubs web site.
Also while I've got you here is a pic of the coupling. Can you tell if it’s bad?
Unfortunately not from that photo.
Sorry for the blow by blow but..... I received the dingle to drain out the hydraulic tank. So, lol, it costs you 32 dollars to drain the hydraulic fluid out. Just one time though. BTW, the books for this machine are $140 from Cat. $110 pdf
Is this the coupling?
That’s cheaper than the prices in Cat’s online shop.
Yes that is the part. I already have one from Cat.
So the smoke/burning smell your wife observed was actually the coupling melting.?
Not sure exactly where it was coming from just that it was coming out of the cover over the rear weights. Now could the engine fan been pushing the smoke around the covers? Absolutely it could have. I’m also replacing it, even if it isn’t bad. One because I’m already there. Two, for peace of mind, three, it wasn’t that expensive. It smelled like rubber, not tire rubber, but the acrid smell of rubber. Could it be electrical? Sure but after an extended look I couldn’t see anything burnt. Also the hydraulic lines were very hot. That leads me to believe that the pump wasn’t turning properly and getting the fluid to the cooler. Not 100 percent sure but that’s what I’m going with. Lol
Can you post a photo of the inside of the coupling where the splined shaft fits.?
Sure it’ll be later today though
No worries. We’re here all week.
As promised. Doesn’t look like anything wrong with it? Also not that I can, but should you be able to turn the pump by hand?
There does not appear to be any obvious failure in the coupling based on that photo. You should not be able to turn the hydraulic pump by hand. HOWEVER if you put a decent-szed pipe wrench over the shaft splines you should be able to turn it with that. I suggest that you should try that before reassembly.
Pump turns easily with wrench. There was something I read something about bleeding the pump? If this is the case what is the process?
Ok let's take this from the top. You saw smoke and lost the hydraulics. What troubleshooting have you done besides pulling the pump to inspect the coupling?
I looked over the electrics it see if something was burnt. Not saying I didn't miss something. At first I went to the pilot switch but didn't look very hard. I do not have a hydraulic pressure test yet. Didn't know I needed one in the first 1.7 hours of ownership. I will however get one. That's about all.
If something wiring-wise was burned up you should still be able to smell it even now. The smell of burned insulation lingers and is hard to miss. I think you would be well advised to test the operation of that switch before putting anything back together. #20 on the attachment. It is a simple open/closed switch with 2 wires. The grey wire connected to the switch should have Batt+ when the key is ON, and that voltage is sent out via the brown & white wire.
I really appreciate everyone's help on this project. I am new to the heavy equipment world and would like to learn more about it. Thanks again for the advice. I will check the switch tomorrow.
Ok after a long week of rain I finally got around to the switch. So here’s what I have. Anyway I made a video but I guess I can’t upload it here. So on the plug there are four wires and the third one from the left as you are looking at the female end of the plug has power. It only has 1.2v the rest do not have any. Not sure were to go to look for the end of that wire. I think it goes to the right console but can’t see really where it terminates
Are you looking at the correct switch on the LH armrest.? The one I was referring to in the attachment only has two wires. Can you check the switch for a Part Number. Also can you upload a photo of it.
I’ll get a picture
See if you have continuity between the black and the black/white wires. if you do then press the switch and that continuity should disappear. Repeat the test between the blue and brown wires. There should be no continuity until you press the switch at which point you should have continuity.
Ok so tested the continuity and I think that maybe the problem. I checked the black/white wires and nothing. Tested the blue and brown wire and that had continuity with the switch closed. (pressed in) Then I checked the black/white wire again and got continuity, pressed the switch and the continuity went away, like it is supposed to. Well ran the test one more time and nothing again. I could not get the continuity back on the black/white wire any more. So I think it is a bad switch.
The continuity between the two pairs should be “opposite”. So for example if you have the switch pressed you should see continuity between one pair and no continuity between the other pair. Release the switch and the continuity between the two pairs should reverse. If you need a switch the Part Number is shown against item #20 on the parts list I attached above.
Right, That's were I think the problem is. With the black/white wire I should have continuity with the switch not pressed, I do not have continuity. With the blue/brown wire, switch pressed I have continuity. I did order the switch
Please come back an update if the switch fixes the problem.
Ok, old switch tested bad, confirmed by on of our technicians, I bought a Cat switch and installed and still nothing. Pump I believe is working a oil level dropped in hydraulic tank when I cranked it up. I don't know what else would cause nothing to work??
Was the new switch tested before installation.? Also it is possible to connect it to the machine harness with the 4-pin plug inverted.? Remember that "new" only means "not tested in operation yet"......... You have to consider that the switch energizes a solenoid that "unlocks" the pilot hydraulic system, so it would not prevent correct operation of the main hydraulic pump. The fact that the oil level in the tank went down when the machine was cranked up proves the engine/pump couling is good and that the pump is turning. Provided the new switch is proved to be operating correctly then the next thing would be to prove that power from the switch is reaching the implement pilot shutoff solenoid. This is mounted underneath the implement hydraulic pump, #9 on the attachment. I think the wire that supplies power to it is brown with a whitre stripe but I could be wrong. Be careful to get the correct solenoid because the other one right alongside it is for the 2-speed travel function.
I do know you cannot invert the plug on the switch. It is an automotive style weather pack connector. Also while I was pulling the switch out the other day I did turn the ignition on and put a piece of wire in the plug going to the machine. I did not see any voltage across any of the wires. Does it have to be running to see the voltage? The switch was tested for continuity before install. It check good. Something also to note is that when the pilot safety arm is up the machine will crank, when it is down it will not. Seems strange to me but maybe that's the way Cats are.
As far as I can see from the electrical schematic Batt+ voltage is supplied to the switch as soon as a key is turned ON. From the Operation Manual.......... Locked - Place the hydraulic lockout control in the RAISED position to deactivate the hydraulic controls. Make sure that the hydraulic lockout control is in the RAISED position before you exit the machine. Note: Always put the left hydraulic lockout control in the RAISED position before starting the engine. The engine start switch will not function if the left hydraulic control is in the LOWERED position. Unlocked - Place the hydraulic lockout control in the LOWERED position. When the hydraulic lockout control is in the LOWERED position, the hydraulic controls are operable. So from that it appears as though the lockout control should be in the RAISED position in order to start the engine then LOWERED to activate the pilot hydraulic system.
Can't say I've ever come across an excavator, mini to massive and multiple brands, that would allow you to start the engine with the pilot lockout off.
Ok then I'll start with checking voltage with key on again. If I don't have it then I find the other end of the plug. Can you tell where it starts/terminates?
LOL, the machines I work will not allow you to start the machine without all the guards and interlocks on. I guess if I see a guard in the open position it's not supposed to start. To me the arm switch is a guard.
Well it gets power from the key switch so I assume somewhere around that area. EDIT: Scratch that. You have the electrical schematic. The power for the safety switch comes from fuse #3.
Ok, checked F3 it runs lift pump and something else, then I looked back at the picture and there is a number 3 on the fuse panel, so is it F3 or 3 on the panel. Any who if I was wrong I'll check it tomorrow. Thanks for the help today.
I have to correct myself here. I mis-read the schematic. The fuse that supplies power to the safety switch is actually F6 (10A) marked "valves & horn". Easy test. With the key ON does the horn work.? If it does then it becomes a pwoer tracing exercise from that point. That's one good thing at least. I know that the switch has a 4 wire pigtail on it but how many wires are there on the machine side of the 4-pin connector.? It is very hard to tell from the electrical schematic. Once that question is answered the next one is what colours are they.? According to the schematic the wire supplying power to the safety switch should be grey and the wire taking power from the switch to the pilot solenoid should be brown with a white stripe. Can you please confirm that.?
There are 4 wires coming in the plug from the harness. 2 white with black tracer and 2 brown with white tracer. I posted a picture in the post of the connector. You can see the wires. I know one of the brown with white tracer goes to the connector for the solenoid at the pump.
At least that confirms one wire colour shown on the schematic, if not the other. So in the absence of the grey wire(s)? I assume that the white wires with black stripe must be the ones bringing power from Fuse F6 to the switch. If there is no power on either of those two wires with the key ON then do you have any way of getting into the back side of the fuse panel to check what wire colours are connected to Fuse F6.?
I will confirm when I get home from work today
Ok here's what I have come up with after investigation. The fuse to F6 was blown. Plug another in and we're good until pilot handle is put down and blows fuse. I then unplug the solenoid and fuse still blows. I unplug horn and still blows. All of that is when the handle is put down. I then unplug pilot switch from the harness and it does not blow. I'm thinking harness now. There is a direct to ground short in the harness somewhere. Now as I'm thinking about it the short should be between the switch and the valve. If it was before it would have shorted with the switch unplugged. It's only when power is sent to the valve. Am I thinking about that right?
That indicates the solenoid is not the problem but potentially everything between the fuse and the solenoid is still in play. I'd say you're right. The switch is new & tested so it's not going to be that. I'd say the problem is in the "Out" side of the harness (brown wire with white stripe) somewhere between the 4-pin connector at the switch and the solenoid. I wonder if it has anything to do with the smoke and burning smell that you started your OP with.? There is a half-reasonable diagram showing harness connections in the bottom LH corner of Page 2 of the electrical schematic. Look for S28 and Y13 on that. Also the attachment but unfortunately neither of them show a 3D illustration of the physical harness routing on the machine.
Thanks for that explanation. I had a similar issue as OP (it was the safety lever switch) on my Wacker Neuson EZ28. I installed my own switch only using one of those circuits and bypassed the other. It works, but still wonky. Looks like I’ll need to switch both circuits. Those CAT diagrams are almost exact copies of my Wacker Neuson diagrams - does WN make the small CATs???
I'm still trying to figure out where the second pair of wires (the normally closed contacts) from the switch go to. The NO contacts obviously power up the implement pilot solenoid when the switch is operated, but the electrical schematic does not show any connections for the NC contacts as far as I can see.
Does CAT have any similar charts to this: It’s for a Wacker Neuson ez28 but everything looks the same to me. Apparently WN made CAT mini-exs until 2018/19. I marked some red lines next to the safety lever switch circuits.
Unfortunately they don't. However S28 on the Cat schematic is shown as the safety switch which ties up with your table. Only the NO connections of the safety switch actually appear on the schematic. However I must say that if the schematic is wrong it wouldn't be the first time........
Update, after a bunch of trouble shooting I thought I found the offending wire. I cut that wire and ran a new one to test, still nothing. I don't know, I think it's time to call Cat. I'm sure it's in the harness and I think I narrowed it down but there is more going on in the harness than I thought.
If it was mechanical I would have already had it fixed but as most people are I'm not a electrical person.
I would suggest that a competent auto-electrician would be a better bet. One other thing. Have you tried applying battery voltage direct to the pilot solenoid with the engine running to see if the hydraulics start operating.? BTW this should be done with care because if everything works as it should the hydraulics become "live" as soon as you power the pilot solenoid valve.
No I have not tried that. I will try that later today. I guess I could start cutting into the harness, I even think I know where it’s at but not 100 percent sure. I could also try a smoke test. Where I just jump the fuse with wire and wait for the smoke. I’d hate to do that but at this point not much to lose. Just keep the extinguisher handy lol
Yes, but if you know the switch is working at one end and prove that the solenoid at the other end is also functioning, then the harness in between those two components is conclusively proven to be the only possible culprit. It would be unfortunate to dig into a harness to find that it was not the cause of the problem.
True.
Ok, tried the direct to battery route. Success!! It worked!! Now I have a choice, and I'd like a consensus. I can run new wires and run it to a switch to turn on and off the pump or dig into the harness. Pros, less money, less time, possibly anti theft, and I don't have to dig around in a harness possibly hurting something else. Cons, not factory, pilot safety switch not working. I would run an inline fuse to a switch off the battery and to be able to use the hydraulics just flip the switch on.
I would temporarily do that to finish up what you need. Then whenever you’ve got extra time try to figure out where your harness is shorting. I’m guessing you already checked the wires in the safety lever area? On my ez28 there seems to be opportunity for the wires to be pinched around that lever point. The black sheathing has already been worn down on mine.
Why not run new wires along the outside of the harness from the new switch you just bought to the solenoid.?
Nige, I did that the other day. It didn’t work. I could’ve got the wrong wires but I didn’t think so. I could try the other one but no guarantees it will work.
Do you have an electrician in your circle of friends.? Using the schematic it ought to be relatively easy for an experienced tech to get to the bottom of it all.
I wish I did. I'll be back when I get it running
To update, I know ya'll were tired of seeing this post lol. Anyway wired in a switch to the battery and the hydraulics were working. Started to put on the weights back on and in the process of that I had to move the machine. Started tracking the machine and OH! forgot to put the blade up. I reached over and nothing from the blade. Well, sh%T, blade doesn't work. Then back to wiring. But I was reading in another post something earlier in the year about a blade solenoid valve. Got me thinking. So I went back outside and put a new fuse in and unplugged the solenoid and put the handle down and no blow. Plugged the valve back in and guess what? It blew. So, would that cause the fuse to blow? I'm guessing yes. What do you think?
When you say “valve” do you mean solenoid.?
Yes the solenoid
Take your multimeter and measure the resistance across the coil with the solenoid unplugged from the machine. Post your results.
Kinda all over the place but settled down on these
With a resistance that is varying and a low as shown in your photos the solenoid coil appears to be shorted internally. The reistance should be in the order to 70 ohms AFAIK.
Confirmed blade solenoid is bad. Unplugged solenoid, replaced fuse, started machine and hydraulics worked other than the blade. No blown fuses or anything. Ordered solenoid.
I just read all 4 pages and wonder how something burnt enough for your wife to see smoke isn't visible ? Should be a fairly large crispy bit of harness somewhere. Joe H
Could be the solenoid smoking that see saw. The smoke was seen from that area of the machine.
So I was thinking last night about the Catjoy's post about his back in March. He and I have/had about the same problem. What I was wondering is, could the pilot switch cause that issue? Mine was bad. Being that that's a 24V solenoid could it be that one side of of that switch was bad and wasn't sending enough volts to the solenoid causing the solenoid to draw to many amps and burn it up?
Last post on this thread. Thanks for all the help. Ran the machine today about 4 hours. I will post a picture of the culprit. The smoke was from the connector on the solenoid.
Only took 5 pages but we got there in the end. That smoke your wife saw when it happened must have come from somewhere.