Back story on the machine. It's a 2001 JD 270LC with 12,000 hours on the original engine, the pump has 300 hours on it. Was used in northern Alberta it's whole life. Long story short i bought it sight unseen and am now stuck with it. Cavitation caused a lot of leaks that have now been fixed or replaced. One of those replaced items before i got it was the swing motor. Along with the swing motor the pump was replaced at the same time but they just filtered and reused the old hydraulic oil. I have replaced every last drop of oil i could, 280 liters. Now i know this is a well used machine and everything works on it but one thing that gets me is the swing motor strength. I'm used to the only other machine i've ever used and that's an EX60. To me it just seems slow and under powered. I don't know of any way to test it or any other machines to guage it against. Is there a test to see if it's alright? Maybe i'm just used to the quickness of the smaller machines?
The bigger the machine, usually the less responsive it is, it's just the physics of inertia and mass. That being said, there will be pressure settings and cycle time specs, need to get information from a dealer or get your hands on the service manual.
View attachment H2 measure slew braking distance .pdf Good day ATCme A worn swing motor will show up when you have poor braking in both directions, it is not the only cause but it will confirm if your swing is poor. See attached Kind regards Uffex
I am sure though you would know if the cycle was too slow.... There would be something wrong with machine if you were this concerned. I work all week at work with brand new 16 t and 20 t Hitachi machines and then come home on the farm to our 25t Kato to use, if somethings not right a good operator just knows
I tried doing this test this weekend. Going clockwise it stops just before the 90 degree mark and going counter clockwise it stops within the 0 to 45 mark. Did it a few times with the same result every time. Sounds like it's worn out to me?
Sounds like a weak relief in the counterbalance valve to me?
Is it fixable? Is it something i can do at home or do i need to call a mechanic in? It's more annoying than anything else.
Probably best to have a mechanic set the pressures on both sides. I believe they're adjustable, there's one for each direction and they live in the swing motor head.
At 12,000 hours it would be reasonable to see all kinds of issues. Usually hoses and rubber O ring seals are good to about 7,000 hours or six years give or take but people always run them till they leak. The relief valves will hammer out or erode the seats over years of use and need adjustment or replacement when they get out in the range of your machine. I would recommend finding someone with some gauges and healthy knowledge of your machines' systems and do a tune up and possibly a diagnostic check. Swing takes a beating over time and likely a pair of relief cartridges is all you need. Good Luck!
Is the relief valve(s) located on the side of the motor or the control unit? If it's on the swing motor i only see one on my parts sheet listed for it.
Shows one in the picture, quantity (2) in the parts list, they're on the motor opposite the main hose connections it looks like. "51 0692704 Pressure Relief Valve 2 SUB FOR AT217926"
Whoops. Didn't see the quantity. The picture only shows one so i assumed. I'll see how much they cost. If they are cheap i'll swap both of them and see what happens. Can't afford to have my mechanic come back for small issues like this every weekend. If i remember correctly they were still yellow. The new motor was painted black. edit- Wow 590 a piece. Any way to rebuild them?
Swap the reliefs and see if the difference in braking changes with the swap.
Ben beat me to it, lol. The zero cost test is to take a wrench and swap the two valve cartridges as he suggested, then test again, should swap sides. If not, dig further.
At $590 each for 12,000 plus hours comes to about $0.10 per hour for both. Did you plug a gauge into the circuits and see what was actually happening? You should also check to see if this machine has a free swing function. You can just swap reliefs but what are you going to do if that doesn't solve the problem? It could just as easily be the motor getting tired.
Swapping reliefs diagnoses the problem, then you get a gauge and adjust, or buy one new one if the other is still up to spec. It ain't rocket science. It *could* be a motor issue, but the cases I've seen where a motor would pull better in one direction than the other is several percentage points to the right of the decimal. Check the cheap stuff first.
So you swap the reliefs and the problem changes direction. Which relief do you replace?
If that's your methodology, swapping parts, it really doesn't matter as you have a 1 in two chance of being right, if you miss on the first go you're only out what, ten minutes? If they look adjustable I would find a gauge and try that first, they probably both are a bit low after that many hours
No i didn't plug a gauge into any circuits. My mechanic would have to do that for me. No this machine has no free swing control on it. I doubt the motor is tired since it only has 300 hours on it like the pump. The relief cartridges do look like the original ones or are reused from another machine. I'm going to swap them around when i get a chance and see if it switches directions. Yes they are adjustable but i was also told by one mechanic to clean them out while they are off. He says once the o-rings break down pieces can get stuck in little parts like that and stop them from doing their job. Doesn't take much apparently. This isn't a full time machine and i'm not an operator. This machine sits on a farm for now and when i get time and money i work on it. I'll keep this updated until it's fixed.
Would this fit my machine? Would it be worth it just for the pressure relief cartridges? https://www.rbauction.com/Swing-Motor?invId=8644978&id=ci&auction=CHILLIWACK-BC-2015159
Fixed the swing brake problem. Turns out it was 4 o-rings or the lack thereof. Swapped cartridges around, no change. Noticed oil leaking out from under what i assume is a bleeding block(?) on the top of the motor but it only leaked going one direction. Took it off and noticed no seal. looked through the parts breakdown and voila there are supposed to be 2 o-rings there. 2 on top 2 on the bottom. Put them both on and now i have a better brake. Still not the greatest but usable and within range. Now for the next big issue. Redoing that 6068. Any suggestions besides buying a Hitachi?
http://www.dieselenginetrader.com/search/engine_search.cfm 60+ listings. You could kit it, I've heard they're not bad to work on.