I am new here but I was hoping for some info on an old case 680G I acquired recently. It is a good running machine with good brakes, good power, and quite dry, I was looking for a service manual on cd but seems the g series are not available? If this is the case I will have to shell out the money for a hard copy which seems to be available. Also the only real issue is the fuel looses prime after sitting a bit, any known trouble spots to check first?
Haven't seen a cd for a G, the machines had two different setups on the main fuel line from the tank, one used a inline check valve to stop the leak back and the other used a elect fuel pump with a check built in I seem to think. The screen filter strainer fitting is different in the tank also depending on if it has or has not a elect pump.
thanks for the quick reply sheepfoot, where would the electric pump be, in tank or in line? as for the service manuals are the reprints worth the money? I think I saw a couple of company's selling them. This is also my first 24v machine, it seems like led lights might be the way to go with there longer life span, I need a few. You seem very familiar with these machines, are these particular about the reverser fluid, I would like to do a full service before winter in the north and was wondering if tractor hydro trans fluid is a good option? thanks again.
In line, between the tank and the engine. As you're sitting in the seat, facing forward, it's inside the frame on the left side, more or less behind the steps. When the engine's off, but the key is on, you should be able to hear it ticking. Open up the bleed screws or the sediment bowl, and it'll tick a lot faster as it pumps. When I owned mine, the manuals were all on paper, and LED lights hadn't come along yet, so I can't really help you there. Case's website is pretty good on the parts manual end of things. I always just used case's own TCH fluid in the shuttle, as well as in the hydraulics. Good luck with your machine. I really enjoyed mine...
You may find this interesting . Enlarge it to 350% to read the lower pages. http://murphyused.com/images/specs/516.pdf
My dad had a 680E. Learned how to dig dirt in that thing. Sorry Digger, never in this life or the next could I say I enjoyed it.
Another thing ,if the rubber "O" ring (#8) is missing on the primary fuel filter you will have the same "losing the fuel system prime" issues.
Thank you all for your replies, I am quite sure there is no electric fuel pump, there is no clicking and I could not find anything resembling one. I will have to check for the o ring. Does Case TCH still available has it been replaced, really not into taking chances on the reverser. thanks again.
Your 680G may or may not have an electric fuel pump according to the parts book. But it does have a strainer in the fuel tank that may be part of you problem. Also there is a check valve (#28) in the fuel line if you don't have an electric fuel pump. It may be leaking and draining the fuel line somewhat back into the tank. It could also be partially blocked with crap. You can view the parts book here ► http://partstore.casece.com/us/parts-search.html#epc::mr52042
Thank you for the diagram, it will be useful hunting this prime issue down. On a side note I was digging today with it and when I went to move some material around with the bucket I used the breaks a few times and then it seemed as though the air pressure would not come up? I let it idle a bit and it seemed to return to normal , but a little later on the same except the breaks did not release fully, I checked the easy stuff, no major leaks, good belt tension on the air pump pulley. any ideas would be appreciated? thanks for all the great info.
Does your air pressure gauge work ? First thing I would look at is the air compressor unloader. It may not be tripping the air compressor to pump when the tank pressure drops. The air line that goes from the compressor to the air tank has a one way check valve . It is used to prevent air from going back from the air tank to the compressor when the compressor is unloaded. It will be underneath the tractor on the air tank. If it is malfunctioning you can hear air escaping from the inlet side of the compressor when it is unloaded.
thanks for the quick reply, I believe it was moving before it definitely is not moving out of the red now. I will have to crawl under there tomorrow. I thank you for your help and hopefully I can get it correct, I just ordered a service manual so that should help significantly. also thanks for the Case site info it will be useful.
The brake system is designed to apply the brakes when the air pressure is below 60 PSI , if remember correctly. It sounds like you have some real issues with an air compressor that isn't working or you have some major air leaks, or both. Try draining the air tank, there is a petcock on it. Look for any oil that may be in it. If there is very much oil in the air tank, the piston rings in the compressor are badly worn and may be part of the low volume of air it is pumping. You could replace the air compressor governor. Doing that will eliminate any problems it could be causing. They are relatively cheap on Ebay. About $20.00. It is an industry standard D2 style governor.
ok I will check that too. so glad this forum is here you folks are great and are very helpful. I will update you on my findings, hope its something easy.
ok one problem down, my air gauge does not work, so I was looking and listening for an air leak when I thought I'd test it out because nothing obvious was leaking I new I had air pressure from setting the parking brake. That's when I noticed the left break pedal not returning, so I picked it up and it moved a bit so I tried it and low and behold no issues, I guess it needs to be used a bit and work out the kinks from years of low hour usage. does this linkage have a spring or grease fittings in it? At any rate I sure am glad that was all it was. Now onto the fuel bleed off, thanks again.
There is no way that I know of to lubricate the treadle valve itself. The stem of it should have a rubber boot on it. But I would think the binding is in the pedal hinge where it is bolted to the floor board. Penetrating oil will do wonders on those hinges. There are grease zerks on both of the brake shafts underneath the tractor.
thanks again Tinkerer you are bailing me out everyday it seems like. I will grease those zerks on the shafts and penetrating oil the hinge. I try to run it everyday to get everything moving. plus I want to find it now and not when it's -20 F. on that note, reverser oil should be of lighter weight? Does Case make TCH for somewhat extreme temps. I'm sure the block heater will help a boat load and transfer some heat but seems reasonable to use a cold weather oil? Thanks again
I don't know anything about Case TCH oil. I never use it. I use an off brand oil that meets Case HY/Tran specifications. You may want to read this thread, Melben is a Case expert mechanic and Mitch defiantly knows his stuff. HeavyEquipmentForums A working block heater is a must for cold weather starting. So is a winter grade engine oil. Equally important is a light weight hydraulic oil in the winter.
I have an update on the fuel bleed off. yesterday I put 10 gallons of diesel in the tank before I ran it. today when I went to start it and checked the hand primer it was firm. jumped in and started it up, don't know if it was just a fluke or it has something to do with fuel levels or just the fact that I've been running it. maybe the oring in the filter was dry from no use? Or pressure from fuel in tank since there is no electric pump? I will monitor this and see where it goes. I also sprayed down the brake and worked it so hopefully that will work off the crust to. Also the air gauge worked today when I turned the key in the on position, it doesn't need to be on apparently because it has a push button starter on it..... should have realized that but oh well. I never did like it when reading a thread and it is left without an outcome so hope it helps someone out.
thanks for that link Tinkerer, it's what I figured. I appreciate your help with all these questions. Now I need to get busy digging. I've been wanting a backhoe for such a long time I can hardly wait to do some serious work with it, or play depending upon your preference.
I'm glad I could help OLDDIGGER. If your fuel problem returns try removing the fuel line from the primary filter and blow some air into the fuel tank. Remove the tank filler cap first though. There maybe something in the tank. Years ago on two different machines I fished rags out of fuel tanks.
I will keep monitoring everything we talked about. I have my service manual in route, so the silly where is this and that questions will stop. Thanks again and I am sure that I will have more questions.
Do you guys know if the case 680g uses the hydraulic tank as reserve air for the brakes?
I don't think they offer TCH any longer. My dealer substitutes CASE Hy-Tran, which was IH Hy-Tran before Case acquired IH. Hy-Tran is good stuff, I believe better than TCH.
Case built backhoes in Iowa, and ?Italy?. I had a 580K, a friend has a 580G same year. Another friend bought the 580G new in 1988, he said the European version was about $20,000 less. They seem well matched, but the G has only flat glass, interior is flat matting, with hemmed edges, screwed to flat surfaces. The K has more molded plastic, curved surfaces. I believe they share the same engines, probably many other parts. If I'm not mistaken, G has two boom cylinders, K has one large one.
No, it does not. The tank air supply line has a regulator in it that limits the tank pressure to 15 PSI. It is pressurized to ensure that the hydraulic pump has oil in it on start-up. The air brakes require about 100 to 125 psi. The air compressor should be adjusted to not go beyond 125. Only the 680's and 780's had air brakes. Unless they are very old models.
Thank you for the explanation. I noticed at one time the hydraulic tank had pressure on it when I went to fill it up. Now it doesn’t. There must be something wrong with the regulator like you said. Also, I hardly ever apply brakes because when I hit them the parking brake knob pops out. Maybe the brake valve is using too much air. It sure seems like the air tank is too small or the compressor can’t keep up. Anyway, thanks for answering my question.
The parking brake knob is supposed to pop out and apply the brakes when the air pressure is too low. The OEM air tank is adequate to store enough air for daily operation. You most likely have multiple air leaks, worn out piston rings in the air compressor, or a simple thing like a slipping belt on the air compressor. Connecting a shop air compressor to the high pressure line on the machine compressor is an easy way to find leaks with the motor not running. I have a valve with a quick connect coupler permanently mounted on my 680.
The compressor seems to be working ok but still might struggle recouping. I’ll take your advise and mount a quick disconnect to it. I know I’ve got a brake with a bad diaphragm on the parking brake side but no spring compressor. I’ll have to get that fixed first. Recently I had to replace the fan belts-that was fun! Thanks again for your help.
Unless you are experienced with repairing an air brake chamber--- buy a new one. The spring in them can be deadly if it isn't safely contained. I would never try to reseal one of them. New brake chambers can be purchased at most any auto parts store, and there are many vendors selling them on the internet. The same is true for the foot valves for the brakes. They are plain ole Bendix valves.
No, I would never disassemble a brake can aware of the parking brake side of it. Just removing it from the machine makes me nervous. I’ll follow what my service manual tells me. I put a pressure gauge on at the air tank and only getting about 53#. It’s enough to hold back the parking brake even with the leaky diaphragm. Definitely not getting up to 100.
You may already know this but other people reading this may not. A cage bolt an be inserted into a brake chamber, and when it is tightened up it will release the brake. That enables a truck or tractor to be moved when there is no, or insufficient air pressure.
✅. Yes. I’ve had to use them on several occasions. I’m sure it’ll be necessary when taking the can off. Now this air compressor: have you overhauled one before?
No, I have never overhauled one. It isn't worth the time and money as far as I am concerned. I have had very good luck buying rebuilt ones on the internet. The first one I bought was on EBay and it looked like it was new when it was delivered. I contacted the seller and he another one. I bought it for a spare. I was getting oil in the air tank because the piston rings were worn out in the original compressor. Case used Bendix air compressors and you should be to find one easily.
Ok awesome. Great information. I may need two too. I’ve got an old Euclid R15 which needs one as well. Thanks.
The air compressors on 680C's are air cooled. Any of the 680's made after that are liquid cooled. Life is simpler with an air cooled one
I agree. That Euclid Bendix compressor has 6 pipes coming and going. What a pain. Fortunately the 680 is air cooled. Idk Mine might just be a governor problem.
The compressor drive belt has to be very tight and have no glazing on it's surface. It also has to have the correct profile it fit the pulley grooves properly. It is very common that someone will put the wrong belt on. I learned the hard way when I replaced my own belt and found that it slipped under a load.
The belt slipped right after I put a new one on because I hadn’t tightened the compressor mounting bolts tight enough. Fortunately I was close to my tools and not 3 miles away with locked up brakes. Perhaps I need to carry the brake spring bolt thing around with me.
When I ran truck, I always had one of the brake release rods in the cab.
They are called cage bolts. Should be available at any auto parts store that sells air brake parts. I would suggest that you carry two of them in your 680 in case you lose air pressure. I always carry a ratcheting box end wrench in the cab with them.