Hi everyone, I am a newbie with a very ugly 1980’s JSW BH40 12-ton digger. Well, the subject line says it all...my Excavator only swings in one direction. But I know from reading other posts you guys like a lot of detail, so here goes: I was making a track the other day, winding up along the side of a hill. I was digging the high ground on the right and dumping it to build up the low ground on the left. As I dumped each load on the left and went to swing right, the swing got weaker and weaker. If my whole arm was extended it couldn’t even swing right at all after dumping a load due to it having to go slightly “uphill” (because of the grade of the track). I would have to bring the boom right in to swing it back to facing the front (12 O’clock), then extend it for the next bite. Anyway, after half an hour it “went” completely. By this I mean it won’t go right at all now, and it won’t even “stop” to the left. I know this because I nudged it left after a fresh bite and she got away on me completely. The whole arm swung left out of control all the way from say 10 O’clock (where I stopped giving left input) picking up speed with gravity from 9 o’clock onwards and it swung a graceful and majestically destructive arc all the way past 6 O’clock to about 4.30 (4.27 to be exact) which sheer momentum. Then it lazily swung back and settled at 6 O'clock with a white-faced driver sitting there thanking his lucky stars no one was killed, or something even worse like whacking my SUV. I drove it back to the flat ground and tried it the next day. Definitely zero swing to the right, but left works fine. Another salient point: it has always been weak to the right, and a couple of sessions before the incident I lost right swing completely for a minutes, but it came back thanks to some skillful emergency praying by me. One last confession, I have done a bit of bashing sideways with the boom extended to break small trees about forearm thickness. Yes, I now know from reading HEF that this is mechanical crime against any excavator and I will never do it again. Please don't ex-communicate me The guy who sold it to me ( $6000 US) suggested I should swap the hydraulic hoses between left and right. If I can then only swing right but not left then presto, the problem is explicitly in my “valve pack”. If the machine still can’t turn right then the problem is in my “hydraulic slice” (whatever that is). I will go and attempt to do this and get back with the results, unless someone has a better idea? Thanks in advance for any input… Ben PS: what a great forum, I have solved 3 problems already by looking at other posts, including the infamous “stalling under load” (yes, dirty fuel and air filters…)
If your swing unit has crossover relief valves on it, I think I'd swap them first.
thanks Atco, I'll research what they are and go and do it...
I'm not familiar with a JSW BH40, so I have no clue how the swing drive is built. If it's anything similar to this pic, there's two cartridge valves that provide crossover relief. This pic is from a Deere 790ELC, slightly larger excavator.
wow, that was fast, I was just heading out the door to drive out to the digger and fiddle with the wrong part entirely, you saved me bro... back soon
photo of swing motor Well, here are various photos. I didn't have the right tools today to actually take anything apart, which is probably just as well because there don't seem to be any "things" that are unmistakably cross relief valves like the diagram above. The 2 orange pipes going into the top of the swing motor are I guess the in and out of the H oil. I suppose that means that fluid flows in 2 directions as dictated by the valves operated by the levers in the cab... if that is wrong, well, that is the pitiful level of my thinking out there for all to laugh at!
If you plan on keeping this machine for a while I would recommend you get a new swing motor. It should come with the relief valves. When I bought my used John Deere 120 it had swing issues. I replaced the swing motor with a new one and haven't had any problems since. Interesting enough when I replaced it I found out it had been replaced once with a reman and well, it didn't last very long is my guess.
G'day Kiwiben, ya got about an odd sort swing motor to be sure, don't really know nothing about that one, but I'm certain you'd like some help sorting out your problem, so I'll give it a wag and see if anyone else has any ideas. I had a sneakin' feeling you would find your unit had hard pipes from control valve to swing motor, makes it kinda hard to "switch hoses" as it were. About the best you could hope for to test your control valve is to remove pipe connections somewhere from control valve outlet fittings or swing motor and cap the lines with proper fitting caps, then start machine and slowly engage swing in both directions. If it loads your engine both ways, control valve likely good, problem in swing motor. As for the swing motor, just taking a guess here, those two square cover plates on opposite sides are likely to have springs under them. I'm thinking that unit has a crossover relief spool inside there that is kept centered by the springs on opposite sides. You could simply have a broken spring on one side. That's about the best guess I can come up with.
Good idea S R E, I'll look into that. Didn't know you could do such a thing. I believe JD's are rebranded hitachis, and JSW's are another manifestation of hitachis, so it is probably useful advice. I don't want to pay again the price of my digger though. The idea was just use it for this one big job and sell it,... but I didn't bargain on all this extra fun thrown in What a deal! Atco, thanks again, you are the guardian angel of many a person on this site. Taking those covers off looks easy enough (Dropping the springs into the dark recesses of the digger sounds even easier and I will definitely do that too... will add about 2 hours to the job I predict) so I'll have a wee nosey in there and see what I find.
I hope you get something sorted out on it. Keep us posted.
It works again! Breaking news! last night after heavy rain it became apparent that one of my track marks had diverted a large gully's catchment to flow straight through my neighbour's lawn. I fired up the digger for some emergency ditch digging, intending to try and do it swinging in one direction. After about ten minutes of doing this, to my great delight the swing motor revived itself in my moment of greatest need. Some would call it a heavy machinery miracle, but I would call it a valuable clue! It was especially pleasing as I had just purchased the necessary tools to begin pulling things apart, and I could see many weeks of fruitless tinkering ahead. What do you think ATCO? Anyone else? It is still a bit weak swinging to the right, but pretty much fully usable. Does this divine revival rule out certain things? For instance, does it rule out needing a new swing motor? Should I still take those covers off and look for a broken spring or something? An important point: swinging to the right there were sometimes some clunky banging noises and jerky hesitations for a split second, a bit like the symptoms of air in the lines i have heard about. I am pretty sure though that after a while it was operating smoothly again. I should pay more attention to these things I know, but my state of religious euphoria at the time of resurrection meant I was incapable of rational thought.
Ill bet the port relief on the main control valve is getting stuck open or has a broken spring. Follow the hoses back to the control valve and look for cartridges above and below the ports on the valve.Swap them out with each other and see if your problem goes to the other direction.
Wow, that sure is a crazy problem you're having kiwiben. I don't know enough about your particular machines components to have many ideas, kinda clueless myself. I would have to start digging into the machines components myself looking for the gremlin. I hope you have some good luck with it.
swinging problem check your oil in your swing box if it got low it could mess the bearings up i have seen this happen before and cause it to swing one way good and not swing the other way
Well ATCO, what are you waiting for? Get your butt over here pronto and start digging into my machine. I can't pay your airfare but I'll pick you up from the airport and give you free use of my daughters while you're here. Sorry that was a lame attempt at a joke.... I don't actually have any daughters, but I have got a few sheep...) 1080 bobcat, that sounds like an easy thing to check so I'll give it a go. Just a couple of tiny technical questions: um... what is a swing box? And um...how do I check the oil? Sorry guys, I told you I'm a total newbie, and I wasn't joking... on the plus side though, i have ordered a manual from Australia so I'll be able to at least find all the parts in the future. I did run the hydraulic oil pretty low because I had a bad leaking main ram. But after I fixed it I put 20 litres of new oil in... maybe it's still low though. I can't actually check the level because the sighting tube has got all opaque. I guess more oil can't hurt though huh?
just check it with the dipstick it,s beside the swing motor in the picture
LoL, I've got plenty keeping me busy here, but would love to see NZ. You can see the handle of the swing box that 1080 bobcat mentioned in your first pic. The swing gearbox is the housing that the swing motor is mounted on. It should be a planetary gearbox with gear oil in it, dipstick to check oil level. Do let us know if the dipstick shows a good oil level and if the oil on the dipstick looks clear.
You guys are very tolerant... thanks, i will do it at dawn, .... then go and check the oil
If that was a Deere or a Hitachi I would say to look at the Make-up check valves. What you have is an unseated Make-up Poppet. The symptoms are weak swing one way but the dynamic braking will work that way. The other direction of swing is ok but when you let go of the swing for dynamic braking it does little or no braking. On Deere and Hitachi machines, the make up oil and the line for it is just before the hydraulic tank and has return pressure to supply positive pressure to the motor. Commonly on Deere and Hitachi machine, when another failure occurs the metal from the failed unit is making its way back to the tank as you are swinging and the motor draws the contaminated oil into the motor. If you swing the other way at the right time a piece of metal can get caught on between the seat and the poppet, giving the above symptom. I cannot see any other hoses on your pictures. Deere/Hitachi machines have 2 direction hoses, a make up hose, (the biggest) a case drain hose and a brake release hose. Check your hydraulic filters!!!!! for metal.
OK, Finally got time to check the digger today. That thing that looks like a dip stick is actually just a hot air diverter for the cab heater. I cannot see an oil dipstick at all. KenAl, my main hydraulic filter is perfectly clean, I think I may have spotted another filter just forward of the swing motor. I will check that next opportunity. I sort of need a translator for some of your advice sorry. But I will hopefully be able to figure it out. It sounds like you know exactly what the problem is so that is great. let's say it is an unseated make-up poppet like you have diagnosed, does that mean I can fix it cheaply?
I'm not going to chew you out over this but, hopefully you realize this probably contributed to your problem. That said I noticed that you have a long stick on that machine. When you have an older machine with a long stick you have to be careful with your swing. Even swinging with a full bucket (fully extended) when your not level will put strain on all your swing mechanisms. It seems to me that putting a long stick on these "smaller machines" is stretching it. When the going gets tough (working while not level, sideways banging, and an older machine) you will experience problems with your swing mechanisms faster then with a short stick. On a side note when I replaced my swing motor a couple of years ago. I bought a brand new one from the dealer for about $3,500.00 US However, I was expecting this cost and had worked it into my budget for purchasing my machine.
Hi again everyone, I think I need to refine my description of my symptoms as they have got clearer over the weeks since this thread started and i have so many possible theories i don't know where to start... here are the facts so far: 1. Every once in a while I lose all ability to swing to the right. 2. When this happens I also lose the ability to brake to the left. 3. After a while the machine fixes itself, but swinging right remains weaker than left. (It has always been weaker) 4. Swinging to the left is not smooth. It involves intermittent loss of swing power for half a second accompanied by a loud bang/clunk before it starts again with another bang. (My finely tuned mechanical deductive powers tell me this is not good.) 5 A fast swing left would have about three of these stop/start pauses to get round 180 degrees of swing. It is especially bad swinging left uphill, or left at full speed on the flat. 6. After working yesterday I noticed a significant (but not massive) leak of hydraulic oil in one of the tee junctions going into (or out of... not sure) the swing motor. It's the T junction bottom right of this photo: The good news is my user manual has arrived (from Australia) so at least I have found how to check the swing gearbox oil, and I will do this today...
By the way, the manual shows a diagram of of my hydraulic system and the top of my swing motor is labelled "Brake Valve". I am guessing this is significant. It's a shame the digrams aren't more detailed...but it's a start
Have you been able to check your swing reduction oil yet? I'm still a noob and I think others have mentioned it but sounds like a possible problem with your brake valve. I think its the block the lines go into that says Kawasaki.
Hi roadrunner. Swing reduction oil? I'm not sure what that is. But if it is the gear oil for the swing drive unit then yes, i have found it in the manual. I didn't quite have the right tools today to check it though... But I made a discovery today of note: That stop-start clunking and banging happens only in one specific arc of the swing, (about 90 degrees between say 5 O'clock and 2 O'clock) and it happens in both directions. My tiny mind is wondering if this means I've stripped a few teeth out of the main Swing ring? Someone please tell me that's wrong? It sounds expensive... I fixed the hydraulic leak by tightening the hose, with my fingers... No rude comments please, i'm only learning here I also pulled apart the two caps on either end of the brake valve block. As you guessed, APCO, there were two springs bursting to get out. They both seemed in perfect condition though... should I pull the whole thing apart? On the bright side, I cleared another quarter acre of scrub today...
Not to sure but I think jsw were an stop gap machine made by mitsubishi....... With reference to the slew ring gear have a look under the boom mount for a removable plate,this should allow access to the ring gear to have a look at the teeth,when you have it open might need some grease. On the Slew motor there are some maker tags get us a picture of them as these may be fitted to another machine............
The oil in the gear case below the swing motor. I almost mentioned the swing gears but did not feel that explained the week swing in opposite direction. If the springs on th brake valve look ok I would concentrate my energy to checking the swing gear like stock explained.
Thanks Stock and RR, I have the model numbers off those maker tags: Kawasaki Type B16 C -A1.2/215 Nikko Hydraulic motor model number HD 35F - 1 - 01 I'll see if i can find a removable plate to check the teeth...
Hi Kiwiben. This is the same slew motor Kawasaki Type thats in the Hitachi UH041. I have a similar problem of not braking and in NZ as well. Can turn left but cannot control the brake to stop the slew from turning. I was told to check the springs in the Control valve where the Kawasaki sign is and alls well. I refitted opposite way and still no change. Not sure how to get the arm cylinder out of Control valve unit to check if any obstacles but I asked the dealer & they said it won't be in the Slew unit but rather in the control valve? still working on it but have you managed to sort it out.Cheers
he's the JSW man, knows them quite well just say adam at robert green said to get in touch offering him a little compensation for his knowledge would go along way! DAVE ELSE EQUIPMENT REPAIR 1276 MOIRA ROAD R.R. # 2 ROSLIN, ON, K0K 2Y0 Canada ph: (613) 477-3062 cheers! adam
Good morning Kiwiben. I as others have said am not familiar with JSW. From what I have read in previous posts here is something else to try. Looking at your pictures if you look closely at the one photos that shows the square plates with the 4 alan headed screws init, now look directly below that and you will see a valve with a lock nut 14 or17mm ?? and a alan key slot in the end. If there is another one of these on the opposite side than we can assume that this is your cross over relief valve. Simply swap these over and see if your swing fault changes sides. Of course it is entirely possible that this valve serves both directions via a shuttle and also it may serve as a make up valve as well. Worth a try. Regards Mike.
One make up check valve might not be seating due to damage. See my previous reply. The check valves are usually good, but the cast iron seats can have damage. Symptom: Good swing one way with poor or no braking that way. Poor swing the other way but good braking. (Note: braking is not achieved by friction plates. It is done by resisting the return oil back to tank. Any frictions would be for parking). By trying to resist the oil from going back to tank with a leaking Make Up Check Valve, the oil has way to get back to tank through the leaking seat to the make up line and back to tank. Swapping the cross line relief valve as explained above is another thing to try or rule out as it can give a similar symptom.
Thanks KenAl & Mike. I now have a better understanding of the slew & its workings as never worked on one before but the diagrams explain to me really well and make sense as does your comments. I think I can overcome the swing problem I have so will work on the valve this week hopefully--never thought of that as my local Hitachi dealer never told me this as they said it would be in the controls which I checked--but then the brake valve is in the swing motor. As said the Hitachi UH041 has the same swing motor. The weather in NZ not too good at the moment & plenty of rain here as winter on us?? but will check when I have time.
Slowly making headway. Pics shows the Slew Changed the make up valves over but the swing still does not stop but was a little better. Could not take out the centre piece [ not sure if this is set in]. I guess next move is to dismantle the slew itself. Pic below shows the make up valves. O rings fine and no sign of wear.
Good morning Kiwiben, These are relief valves Looking at your photos it looks like the valve on the left has a broken O ring, Did you replace this? Also what you have here is the pilot section of the valve, you need to dig deeper into the cavity to remove the remaining parts which should look like a sleeve with a seat in one end and a smaller seat in the other to accommodate the needle part of the valve. You also need to check where the sleeve part seats in the casting as this can be flogged out at times. There still should be makeup valves somewhere unless they are part of the reliefs. Good luck Mike.
Thanks Mike. On the relief valve at the end is an allen screw with lock nut but seems the nut is set on to the bigger nut so didn't want to force it. The O rings are OK on both just some play in this space & no leaks but I will insert new O rings. Youre right. I didn't want to force the inner part out in case it was fixed inside & I would damage something but will give this a go now that it could be the problem and check before I do anything else. It seems to be seated well inside. I tried tapping it but then left it thinking it may be fixed. Yes there is a seat either end I can feel. I guess its OK to tap out so will do this then can check the seats. The machine has only done 3000 hours total.
Hi Mike tried to tap the sleeve out?? boy its stuck hard. Not sure if it must be pressed out to show sleeve & end seats. Just wondering if this part has circlips or must one use a press as trying to do the job without dismantling the slew.
Doesn't sound good. I have inserted a drawing of a different relief valve which shows a sleeve somewhat the same as you should have. I have written in red to show you. Please disregard most of it except you can see the needle and seat which you already have. As I said I am not familiar with what you have but I hope this will help.
Thanks anycase Mike. Do not have a manual to check against a diagram of what I exactly have. I don't want to force anything so will try to get more advice on this before I dismantle the slew itself.As said it was a little better but still not braking when I release the levers to try and stop the swing.
Going out on a limb here but brake valve on my UH10-2 looks very similar other than the thin block between the brake valve and the swing motor. my manual shows a side with relief and a side with a centering spool I think. On my machine the side with the square plates have the reliefs and the bottom side has the centering spool. I'm wondering if that centing spool could be located in the thin block between brake and motor? just a thought.
Hi roadrunner. In my pic #34 where you see the rachet I wanted to find out if the inner part is sealed or not as that seems to be where my problem is but not knowing I am guessing as no pic to show. The plate in front of the rachet with the kawasaki sign on it I am not sure what that is either but will try to find out. As said my other alternative is to take the whole block off and take to a Hydraulic Ex engineering Co I know for advice also but will show them pics etc Monday to see what they say. The square plates with 4 allen keys bolts above the rachet are on both sides and I checked that for wear and all seems OK. Just cannot stop the swing ---- thanks anycase for your advice.
Still not sure what the problem is Just back from overseas. Am told best idea is to take the whole slew out as could be the seals but again the Engineering Shop cannot be 100% sure this is my braking problem I need to solve. I seem to be back in square 1 again. Any thoughts anyone
Did you ever fixed it and how?
I'm guessing their problem was never solved,. I'm having similar problem with swing on my AR-15A Airman minihoe. It swings to the right but not to the left, will swing completely around in a circle to right but not to left. Did the gradual thing for the longest, slow to the left then suddenly just quit. I changed all filters but still won't swing to left. Im wondering where to start looking now
My ex used to swing both ways. So, we are not married anymore. Wait a minute. what? What are we talking about.