I've been having trouble with the Tach Failing within a minute of starting and at the same time the Alternator light on. This tells me to check the ALternator as both are fed by the ALternator. Belts are good and tight, Harness connection checked, and Alternator removed and shop tested good. The machine does start and the battery seems to hold good charge. I am in the process of checking every connection and testing each wire of the harness. No Corrosion found so far. My question is: are there connectors underneath the Backhoe that are not indicated in the manual? Would a defective key switch cause this problem? Besides the Alternator Light glowing and Tach dropping off, I also have several other meters that don't work and the Voltage meter is reading 8 volts when in fact it's 12 volts. I'm also checking all ground connections and Ground Straps. I have all the schematics and part books, but sometimes we suffer from too much information, perhaps one of you might have some good tips. On another note, I have thought about replacing the instrument panel and building my own. Does anyone have an Idea if the case sensors and sending units are compatible with aftermarket gauges such as Temperture, fuel, Pressure, Tach? Or how I can I find a replacement? as mine looks totally beat up.
When the alternator light comes on, can you get a reading with a digital meter?
I just wanted to add myself to this thread, I too have a few gauge problems with my sk. My tach works, but the needle bounces (on all the gauges) from time to time. I too have checked all my grounds and whatnot, but I could very well be missing some due to the fact i dont have a book with the schematics. Please keep us informed if you find the source, I for one would be very interested in figuring it out myself. I know these hoe's have electrical problems, but it sure would be nice to solve them, otherwise they are great!
Is there a dedicated terminal on the alternator for the tach? I am very poor at troubleshooting electrical problems , but the alternator repair shop I use would give be another alternator to try for a few hours, just to be absolutely sure. If you went to a mechanical water temperature gauge( assuming the line is long enough), and the same with the oil pressure( I won't use anything but 1/4" hydraulic hose), then it's just the fuel gauge and tach to wonder about. Do you really need the tach? When you go to sell the machine someday, some people get very suspicious when it's not working though. Phil
580SK Electical Problem After following the Repair Manual, I have determined my gauges are good and sending units are good. The Tach Terminal on on the Alternator is good. My problems are definately wiring or grounds. So I'll be doing a lot of tracing. As for the console rebuild Idea, a we're going to keep all the meters and use the housing. The PC Board has problems so we are going to hardwire light bulb sockets and reuse the meter Bulb overlay and replace the plexiglass. A nice neat harness will be made and new plugs to the wiring harness. You guys that own SKs may aready know about the problems with the CAB Relay location and the Rust and corrosion that happens there. I have a sheet metal man making a stainless console to replace the plastic. It's my mission to find every ground and Strap clean down to the metal and use a electrical anti corrosion compound when reassembled. There are a ton of grounds attached to the chassis. It's finding them. I may run a #8 ground separately for the CAB relay and Fuse box area direct to the Battery Ground Strap. Special attention will be paid to the Engine Ground Strap.
May I suggest trading the machine in. I had 2 K's and they all had problems electrically. The E's and the L's were awesome machines, but the K's had many problems.
Are you kidding? There is no-way(even with the ele. problems) I would trade my Sk for an E!
I dont know I had nothing but problems with my K's. I have one 580SL with 9600 hours on it, never did anything except a starter. The 580E's helped put me in business. Everyone I know that had a K had plenty of problems with it. Maybe you've had good luck.
Trade In....??? I suppose I'm frugal when it comes to Trading In Good reliable equipment with Minor problems. Once you find a machine that you grow comfortable with , If you maintain it properly, it can last years and is as good as money in the bank. . The costs to rebuild Cylinders and pins/Bushings is trivial in comparison to trading in for another machine. Trade In Values are Low as demand is lower than it used to be, and New Machines are rediculously priced. Greasing the machine every 10 hours can get old, but I'm going to do it because of the hard work it took me to replace the Pins and Bushings. The bottom line with me is it's cheaper to buy good parts and repair the problem than to trade and pay too much. Different strokes for different Folks. And I must admit I'm a better mechanic than an operator. How many operators do you know that own 1 inch drive Torque multiplier. I have the cost of rebuilding Cylinders down to the cost of a Kit. About 25 bucks. Sorry.. Bragging.
a bad alternator will do just as you have explained..
well maybe i should explain a little better, i have seen alternators check good but only be putting out half. if its a newer style with the voltage regulator built into the alternator id say your alternator is bad even though it checks good..and if its the older style with an external voltage regulator id start their and replace the voltage regulator frist ...
Thinking back a few years and having worked on many machines since, I seem to remember fixing a similar problem on an SK. If I remember right, there is a fuse block mounted down on the frame below the right side front cab corner. I believe this powered the dash unit. And I don't remember seeing it in the wiring schematic. Check those fuses and also the block for corrosion ect.
580K series I and II and SK were notorious for bad W terminal wires. The harness to the alternator rubs through and or the wire breaks. Pull the wire( i believe it is yellow) off the W terminal at the alternator. Start the machine and us a multi meter set to AC VOLTAGE. You should see 8 volts AC at the terminal. If you have 8 volts at the alternator put the wire back on and test at the dash. Usually we just run a new wire tie wrapped to the existing harness. Now if you don't have 8 volts then the alternator is the problem. It will not be a voltage regulator as the W signal is directly off one leg of the alternator.
I have seen this problem many times in the shop. The fix is this. Install a diode at the excite wire. This will cure the back feed of electricity. If you have the original wiring going to the Alt. It will be the green wire. Hopefully this helps.
I know this is an older thread, but I have a 93 super k with the same alternator prob. Sometimes on mine you can rev the motor wide open & the tach will start working & alt charging, why is this?
My 580SK has a green wire going to the alt? Is this the one the is supposed to have 8 volts? Thanks
Also the brakes on my 580SK are out, I think it is going to be a seal or something. You can fill the master cyls & push the pedal a time or two and they are empty again but there is no external leak, any ideas? Thanks
Welcome to HEF Ditchdigger67! If your fluid is disappearing & not seen - it is leaking into the transaxle through the brake seals. I hope you are topping the master cyls with hyd oil & not dot 3 brake fluid.......... see this post for some info HeavyEquipmentForums (take note of advise regarding removal of transaxle to repair) If you need specific help you should be able to start your own thread, as you now have 3 posts.
Thanks man, actually I only filled it 2or 3times with brake fluid, I will try hydraulic oil it might stay in there longer.Thanks for the info.
Having brake fluid in your transaxle is bad news, brake fluid is very corrosive and destroys many seal materials.
Ditchdigger67 Post #13 maybe There are three wires to alt > Big red wire power to batteries = That was easy > one wire plugs in = Tachometer > one small wire bolts on = power to excite and start the alt charging --- With ignition off no power - ignition on should be minimum of 10 volts
The dash and wiring on these SK units was not great. The W wire was always a problem. The dash in those macines are easy to trace the path, Use a spade connector and crimp it on a length of wire and plug it into the W socket at alternator. Run the wire along the RH frame rail and into the cab up to the dash area. Unplug the dash connector, the wire from the W terminal is the same color from the alternator to the plug green/yellow I think. Cut the wire 6 or 8 inches from plug and solder in the new wire. Noiw take some fine emery cloth or sand paper and make sure the connectors at dash are good and clean. This should solve the problem. Another cause of a tach bouncing is if you have the cold start package (dual battery) and one of the batteries is dead or almost dead it will cause an erratic tach.
Thanks!
I trouble shot my 91 K last fall when I bought it for this problem, found the W wire was broke/melted 4" from the alt. so soldered a new wire from the break with a spade to the alt. and then the dash rpm and charge would work when rpms increased to 3/4 throttle or more and remain working at any rpm until I shut it off for the day. Recently, after sitting for a few weeks, it will not work again so finding this old post is great for the new investigation. thank you 2
It seemed like the only way to be able to keep track of it and not lose the post, was to respond... with a thank you. Cheers.
yes, it would be nice to have a save option for relative helpful info on here. I printed the page to add to my book notes. I just checked the W terminal and only have .037 ac V so seems the alt. is bad, going to have it checked. I think there must be a connection in the alt. that corrodes from sitting ?? I will post later on the test and fix.
I took the alt. to a ele. motor place and after testing it on a machine confirmed it was dead. Don't know why it took so long to finally burn out.. He also hooked up the new one and it showed a good charge, 14+ v. He said the AC volt @ the W terminal will be half of the output DC voltage. But, hooked up the new one to the hoe and it also would not charge or run the tach, none or very little AC volt at the W terminal, Until I sped up the idle to almost full and then it kicked in.. Wondering now if this is normal for these to only start to work when rpm's are high? I will ask the ele. guy tomorrow.
There are self-exciting regulators available for Bosch alternators that eliminate the need to speed up the motor to start charging. I don't about your particular one.
Ok thanks, on a sidenote, when I brought the alternator in for testing the first thing the guy said is where is the fan? Apparently previous owner replaced it with one that didn’t have a fan. Also, to get that pulley off the alternator, he took a socket and hit it very hard with a hammer three times before it would loosen There is a retainer inside the pulley that prevents it from coming off or loosening . I am very sure I would have ruined that pulley if I had tried it myself with a puller. So that’s the good, bad, and here’s the ugly. It wasn’t until I got home and looked online for that alternator and the very same thing on eBay sells for $80 with shipping. I paid $195.
Hey Tinkerer, thanks for this. Would you by chance know the part number of the Bosch that would fit my 90's 580SK? Cheers.
Case #A187623 is the Bosch OEM. They are used on Case, John Deere, Caterpillar, Ford and a lot of other mfr's of equipment. Less than $80.00 for an aftermarket brand on eBay.