Hi folks. I have a 2003 Yanmar Vio 50 and the left track goes slow. I've checked the track tension and they are not too tight. The controls seem to be adjusted properly, with the spool valve having equal travel on both sides, but that is just by me visually inspecting the valves movement. I should mention that I did a recent rebuild of the swivel joint for a different problem, but the tracking issue did not change with the swivel rebuild. I'm thinking the travel motor may need a rebuild, but how do I test it to know for sure? Also, anything else I should be checking? Thanks guys.
Good day A common issue with the small machines is often the pedal is obstructed or when cable operated is not adjusted so good. See attched forr more tips. Kind regards Uffex
I’m curious to see what you figure out, there’s a guy on utube with the same machine and same issue that also already went threw the swivel joint because of a issue with the back fill blade. I’m no expert but I was assuming the swivel would have been the issue.
A friend had a similiar issue, he switched the lines for the drives at the pump to see if the problem duplicated to the other side, This told him the drive was in need of rebuild on the bad side, but, he decided to do both at the same time. What it did so, is gave him the problem answer.
Good day Additional information that my help, the link is for a large file much applies to smaller machines. H2 Weak crawlers P1.pdf drive.google.com Kind regards Uffex
Hey BP. Is your youtuber also named Jon? Yep, that's me.
Hi Uffex. Thanks for the additional info. I finally got around to testing this trackingh today, and was going to swap the hoses to see if the problem moved to the other side, only to find that the hoses aren't long enough to reach. Can't even do the swap at the swivel joint, no slack at all. It would probably be possible to swap them at the control valves, but that would be a major job in itself. I'm thinking I may just rebuild the travel motor on that side and see if that fixes it. Probably less work than doing the hose swap. I can add that the left track is always slow, in both forward and reverse, and in both hi & low speed. It is also weak compared to the right. I've checked the pressure at both piston pumps and they are dead on at 3550 PSI. I am also having a new problem with the machine where the gear pump is failing (posted in a different thread), but the tracking started long before the gear pump issue, and hasn't changed at all. Now I get to see how much a rebuild kit costs...
So, here's an update. I was going to price a rebuild kit and just do the rebuild, but they don't sell a rebuild kit for my travel motor. The dealer gave me a price on all the internal seals at $1000. I checked with aftermarket companies and nobody sold parts but just wanted to sell the whole drive, the cheapest I found was $2500. Dealer price for this drive is $5500. So suddenly it became worth it to be 100% sure of the diagnosis. I ordered some hoses so that I could switch sides and...it's a darn good thing I did, because the problem switched sides too. It's not the travel motor...and I was totally convinced it was. Phew! I've already checked the output pressure of both piston pumps, and they are 3550 where they should be. The controls for travel are directly actuating the valve spools, so I think the problem must be in the control valve. Anything else I'm missing? And then, I've never worked on a bidirectional control valve. Is it something I can rebuild without taking the whole valve block off of the machine? That would be a LOT of hoses... Advice appreciated.
Good day I suggest you make the check attched before you jump into the main valve. Kind regards Uffex
Thanks Uffex. Recall that I had this tracking problem prior to rebuilding the swivel joint, and no change in tracking symptoms after the swivel joint rebuild. (Repair of the swivel joint did fix the blade cylinder drift issue.) I'm pretty confident that it is not the swivel joint. That said, I don't have fittings to do the testing you suggest, but I can go buy some if really necessary. I'm thinking pulling the spool out of the control valve might be the easiest course of action at this point. But it looks like there aren't any internal replaceable seals from what I can tell. Maybe I would find damage on the spool and could replace that (if I'm lucky), or if there is damage on the valve body would have to replace the whole valve. Is my thinking correct?
Good day Jr There are no seals in the spool slice, it is less probable that other that replace there is little to be done. The last post describes checking the main line pressures. You can do this by simply plugging the main line's from the slice with a pressure gauge. Run it up to temperature and check the pressure. Shut the engine down to idle speed while holding the spool in the opretive position. Observe on the gauge how quickly the pressure disappears towards zero on both main lines. If it sinks quickly means your spool - slice is leaking pressure, it gives a very good idea of the spool - slice condition. Keep in mind that seals in the central joint can still be where the problem is at. Kind regards Uffex
Wouldn't blocking the track and measuring case drain volume on each side stalled be more prudent if the travel motor is suspect? Or, assuming you have caps and plugs, switch the motors side to side to verify the issue, since the hoses can't be swapped? But, I'd case drain test first.
Heymccall, just want to clarify that I did buy extension hoses and ruled out the travel motors as the problem, because when the hoses were switched the lazy track symptom also switched. At this point it's gotta be the control valve or the swivel. Since the swivel was recently rebuilt with no change in this symptom, I'm leaning heavily toward the control valve. I'm going to do some tinkering and testing and I'll let you guys know what I find. Thanks.
This is quite timely as I have a 2006 Vio27 with near the same issue. I had an issue with blade down pressure and weak travel motors. I tested and found the joint bypassing, so removed and re sealed it. The blade works great now, and there was some improvement in the strength of the travel motors but it just doesn’t chug along like I’d expect it to. I removed the case drain lines for each motor and check the stalled bypass through the entire rotation of the motor (or where I could lock it up/index it on the sprocket) The service manual does not give an expected flow rate, but after stalling the motor for 1 minute I have maybe a liter of fluid. Both motors bypass about the same amount. I am no pump guy, but this seems ok to me? Please correct me if I’m wrong. I’ve re sealed and set the system reliefs to 2900lbs as the book specs out. I have not measured pump pressure, however I would be lead to believe that if the system reliefs operate as they should then the pump would not be the issue? Once again, please correct me if that is the wrong assumption to make. The symptoms I have are weak travel, an inability to track up a hill at high speed (as in, high speed selection makes no difference when traversing up a hill) and the boom will not pitch the machine all the way back without help from other functions. The boom, bucket and left side travel motor are supplied from P1, the other functions from P2. I am starting to lean towards the main control valve which splits the valve bank. Both travel slices are on either side of the main control valve slice, and run off of the system reliefs. I have plenty of pressure, but I seem to lack flow? However in my head, if I lacked flow I wouldn’t be able to make pressure. Again, please correct me in this respect too. Long winded but hopefully someone may have a bit of insight.
Update. I cobbled together a test rig, but the results are less obvious than I was expecting. I determined the hoses that are pressurized for forward travel on both control valves, (it turns out it is the most forward hose on that valve.) I removed them at the upper swivel and capped the swivel connections and put a test gauge on each hose, hoping to do the leakage test Uffex recommended. So the valve hoses dead end in my pressure gauges. I then put both travel controls forward and move the throttle from full to idle, watching for how fast it leaks down. Here's the problem. There's only 200 PSI difference between high speed and engine idle, so there's not much movement on the gauge. When I go from high speed to idle, both sides drop pretty quickly, but I _THINK_ the left side (bad side) drops faster. If I kill the engine both immediately go to 0. If the valve would stay in the travel forward position when the engine is killed I would be able to watch it bleed down over several seconds and get a much more reliable result, but killing the engine immediately drains everything to tank, so can't do that. However, I may have a result yet. When in low idle, the left (bad) side does something a bit odd. The pressure gauge bounces around between 0 and 3500ish, pretty fast. I would guess twice per second. The right side (good) doesn't do that. My theory is that at low idle the flow is low enough that I'm able to "see" the leakage...maybe? It's like it builds to a certain pressure and then it leaks and the pressure drops rapidly, then it builds again, and just cycles like that. The right side pressurizes and then stays stable. So does this count as a definitive result? Your input is much appreciated.
Jrhook perhaps this could indicate a leak on this section of the valve? May be worth pulling the spool and seeing what it looks like. The farthest passages on either side go back to tank.
Thanks Bibendum. I was thinking of pulling the spool and taking a look, but will need to drain the tank for that. If there's a way to make my test more definitive it would be nice, so I'm hoping one of these pros on here will give me a tip before I go that route.
May be able to put the tank under vacuum?
Ok, so I pulled the spool and really didn't see anything wrong. I measured it with a micrometer in multiple places and it was consistent at 0.498". Actually 0.4985-0.4987 throughout. Minimal scratches under magnification. So I pulled the spool for the good valve and it measured and looked the same. I tried to look inside the valve body but can't really see. So nothing definitive. Then I had a eureka moment. There are 4 possible causes, the pump(s), the control valves, the swivel, or the travel motors. I've checked pressures at the pump and they are good. I swapped the hoses at the travel motors and the problem switched sides, so motors are ruled out. It's either the valve or the swivel. Well now, all I have to do is swap the connections between the valve and the swivel. If it changes sides then it's the swivel. If it doesn't, it's the valve. Gotta be. And I'm already halfway there because I have the hoses disconnected from the swivel for my previous pressure test. When I get a chance to do this last test, I'll report back.
Hey Bib, I'm no expert but I'll give you my thoughts. First off, the top speed on these motors is pretty slow. Mine is 2.5mph I think. You might measure out a distance and time yourself on flat ground to see how close to spec your speed is. I'm not a pump guy either, so I don't know if a liter is reasonable, but that sounds decent to me. How did you set the system reliefs if you haven't pressure tested? (I'm a farmer not a hydraulic mechanic, serious question.) It sounds like your travel is equal on both sides? Pretty unlikely that both motors are getting equally weak the same amount, or both valves are leaking the same... Or both P1 and P2 being equally weak. Seems odd to me. If I were you, I'd want to have 2 gauges, one on each piston pump, and see how much pressure you are getting as you travel. Or just do one at a time with 1 gauge. I suppose if the pumps had internal leakage, they could generate enough flow to reach a high pressure, but with the travel motors in operation the pumps might not be able to make enough flow to keep the pressure reasonable. If that makes sense. My system relief is 3555PSI, so when traveling in low speed I run at about 2500PSI, and at high speed about 3400.
JR, I just got in from doing the same thing. I found nothing out of the ordinary in regards to the spool. That said, I was checking the main control valve, not travel motors control valves. You can see where it has rubbed in normal operation but nothing you can catch with your fingernail. The bore was also a chore to get a good look at so cannot confidently say if it was worn or had a crack between passages. Pilot pressure was just where it should be, about 500lbs. In regards to the system relief, i have the correct pressure. For some reason I thought there was a second set of reliefs at the pump. I’ve yet to measure any pressure at the hoses (mainly because I have no JIS fittings here, or at work) I think that will be the next course of action, tommorow. I will be interested to see what you find in regards to swapping hoses. I believe I’ve gone down the “garden path” a little bit with this one. I work as a maintenance troubleshooter at a manufacturing facility and it’s an easy thing to do. Oh well. Maybe the machine just doesn’t perform like I believe it should? Haha. My old Kubota would flip itself over for a joke if you wanted it to.
So, I only swapped 2 hoses, the 2 that are pressurized when you travel forward. So in forward travel, the right motor is being supplied by the left valve. But in reverse, those are the return lines, and the left motor is supplied by the left valve. So it confused me at first. I have a lazy left track problem, but with this test in forward, the machine went right. Then in reverse it went left. In forward, right track was lazy. In reverse, left track was lazy. In both cases, supplied by the left control valve. So, it made me scratch my head a bit at first, but I'm confident now, the left control valve is the problem. Do you have any idea what a valve like that is going to cost? I assume you have to stick with the OEM...or does anybody make an aftermarket that is identical?
Not a clue. I can’t seem to find much aftermarket for mine, mind you I haven’t called the dealer. That said, when I priced the swivel seal kit, dealer wanted 650$. Found a genuine NOK seal kit online for 250$ cad. I know that komatsu had a pc27 of the same vintage that is an identical machine. Komatsu will possibly carry much of the same parts, however if you give them a yanmar part number, the number must be headed with “YM” Worth noting, but you’re positive the relief valve is not bypassing?
Also, on the end of the valve bank should be a sticker with the manufacturer of the valve bank. Mine was made by “Wabco” I imagine you’re may be the same.
I'll see if I can find make and part# for the valve bank tomorrow. Then start the part search. Good to cover all the bases, but I'm sure it's not the relief valve. I checked the pressures which are good, and also traded the PRV with a different one without any change.
Good day You two guys are making a lot of questions some are easier to answer I will try to help out onece I have consumed all the teat. Kind regards Uffex
Good day I have taken a look at your notes here are a few observations that may help. Kind regards Uffex
Good day One attchment to go.
Thanks so much Uffex. Great info. And yeah, it makes sense to me that the spools will look fine while the valve bodies accumulate all the wear. So I'm 100% sure I need a new left travel control valve. I have a couple additional questions. Do you know a ballpark price to expect on a valve like this? And is it standard to stick with OEM or are there aftermarket valves available that will fit in with the rest of the valves? Finally, should I change both travel valves while I'm in there? Seems odd in a way, because I'm not going to change all the other valves, but travel is special. They both need to work the same or you don't go straight. If some other function is a bit slow, it's not as much of a problem.
Good day Jr I'm not too sure which manufacturer Yanmar use for main valve supply, if we can establish this we can try and find a dealer local to you, or at least find a source. I will try from this end, let us hope we can strike lucky. As a matter of interest, if you measure the bend over 22 meters or so, how bad is the problem? Kind regards Uffex
It's bad. I would say in 20 meters I would be off by 20 degrees. I constantly have to redirect the machine when tracking, even short distances. I can't read the tag on the valve block, it is in Japanese, photos attached. The numbers on the tag are: C0070-23202, 02-04 343. (I think 02-04 is the date.) I also checked my parts manual for this machine (Yanmar VIO50-2), and the part number for the left travel valve is 172460-74150. Machine serial number is 21376B.
Good day Jr Has the block three or four stud fixing? Kind regards Uffex
Four studs.
Good day You have done a lot of work and I appreciate that you have kept me informed, I do not suggest you change the valve slice, as my study of the problem concludes this is an inherent product defect. I would not like you to change the slice and find that you have not solved the issue. I believe this is a pump bias problem in as much one pump is delivering a higher flow than the other. While we do not have a flow meter at hand, we can simply join the two pump lines together and then test for straight crawling. If this resolves the straight line problem, we have a solution which is not so expensive. Many machines have what is refered to a straight line crawling valve which couples the two lines when operating the machine in high speed. I am reasonably convinced that this is the cause and cure. Keep me informed and I will work with the solution.You may try switching the main pump lines for a test. Im not so sure how this may work out. Kind regards Uffex
That sounds like good advice to me. I will be doing that to my machine once I’ve had a nap after my backshift. How many hours on your machine JR?
Interesting. I will swap the pumps and see what happens. This solution would sure be a lot easier than new valves! Thanks for the advice. Bibendum, the machine has 3200 hours on it.
Wow, the plot thickens. So I swapped the lines at the pump, and....now it tracks much better. A very slight right deviation but not anything to be annoyed by. Maybe a couple degrees in 20 meters. One thing to consider, there is a hydraulic pressure accumulator on the output of P1 (as it was set up). The way the fittings are I had to swap that as well, see the gold cylinder in the photo attached. It doesn't show that in my parts manual for the machine, so I don't think it is stock. Why would somebody have put it only on 1 pump? Here's the interesting thing. P1 is the bottom port which drives the right track, and it had the accumulator on it before I swapped lines. Now P2, which drives the left track has the accumulator and the system tracks better. I don't think the accumulator could have anything do with it, could it? I'm assuming I had a slight decrease in flow from P1 compared to P2, and then a slight increased leakage in the left valve. The 2 together made for a big tracking difference, but with the pumps swapped they are much more balanced. Any reason I shouldn't just leave it like it is? Additionally, I could still couple the 2 pumps together, though I wonder if that would affect its function in other ways, like when trying to do simultaneous functions like bucket, boom, and stick together. Wouldn't it make the machine operate a bit differently? Hydraulics are awesome...and tough. Thanks guys.
Good day Jr You do not waste any time do you, for me to give you good advice I need a hydraulic schematic which is correct for your machine, that is why my previous advice was a little apprehensive. While we have identified the cause and cure which is positive, leaving it with the changed lines, I'm a little uncertain. As to the accumulator installation, my thoughts are much as I have already stated. If you have a contact with a manual, these will normally have the hydraulic schematic. Kind regards Uffex
Uffex, In your experience, what have you seen as the normal/typical cause for a reduced flow capability of an axial pump? Is it more often that the valve plate becomes worn? or is it that the pistons or their bores become worn, causing a reduction in flow?
Hey Uffex. Gotta get this darn thing fixed! ;-) I've attached the schematic and also the whole hydraulic section of the manual if you want more info. My machine is a ViO50-2 with quick coupler, schematic on page 8.
So I took it out on a straight section of road and timed it to gauge it's speed. I discovered that the deviation to the right (still have the pumps reversed) is bad enough that I need to fix it. I'm going to couple the pump outputs together. I figure if it causes any issues with the rest of the machine operating, I can put a manual valve there and just open it when I have to track long distances. I doubt that will be an issue. Since we will be coupled together, it really won't matter where the accumulator is. Speed was pretty good, even having to correct direction several times. I calculated 2.4mph, spec is 2.9, and if it were going straight I would have been very close to that. So that's my solution. Thanks guys. Bibendum, on my little joyride I tested to see if the boom could lift the machine alone, and it does, no problem. Maybe check the relief valve pressure you are getting with your boom function. The PRV on that valve might be too low.
Good day Jr As I have interpreted your most recent post with those lines crossed we still have the problem but has it switched to the other side?
Good to hear (kind of) JR. Too bad the pump is on its way out, but maybe you can find something in the mean time while you can still run the machine. I'll just reiterate my symptoms- - Lack of power when tracking / pushing material - No difference when high speed is selected while traversing an incline - Negligible difference when high speed is selected on flat ground - Lack of power in left track compared to right track (this was not as apparent in my machine compared to JR's by the sounds of it, as the machine did not have a noticeable drift when traveling so i did not choose to bring it up, however it was apparent) - Boom alone will not raise/pitch machine without help from other functions *Ive verified and resealed system reliefs. *Ive verified case drain of each travel motor *Ive verified condition of swivel joint *Ive verified pilot pressure *Ive verified mechanical operation of travel valve linkages *Ive verified operation of high speed travel (both electrically and hydraulically) *Ive verified there is no restriction in return flow to tank *Ive verified, as well as possible without removing valve bank for further inspection, the condition and operation of the main cut off control valve Uffex's point of reduction in flow in one side of the pump verses the other made good sense. Since I also had a somewhat lazy track, swapping lines seemed like an easy way to test as the fault should move to the other track. Swapping lines showed a transfer of the lazy track from the left to the right side, which to me, narrows the issue down to the pump. I will not say this is definitive yet, and plan to drop by a friends place to flow test each side of the pump. Assuming each pump in either machine is worn, i am of the opinion that JR's pump has more significant wear on one side of the rotary group versus the other, while the wear is more even across both rotary groups, however still slightly more pronounced on one side, in my machine. I believe it would make sense that we do not see a reduction in system pressure due to the "horsepower control" capability of the pump, up to a point. Referencing the chart I've attached, the maximum force "F2" has remained constant due to the system reliefs, maintaining the capable pressure. Load "F1" has, in 3 of four scenarios, never changed, and the pump is still capable of suppling system pressure. However due to wear either in the pistons, barrel, valve plate or a fatigue in the spring, it supplies this pressure at a reduced flow rate, which is most noticeable while tracking, especially in high speed. So I did what i was apprehensive to do from the get go, I turned swash plate adjustment screw in, by 1/4 turn increments to a max of 3/4 from original setting, and monitored system relief pressure, where there was no change. This may be an indication that the spring did not fatigue. The pump now takes in more fluid by volume, making up for the bypass. The machine now tracks at an acceptable speed and has no issues pushing material. I'm not considering this a fix until i flow test the pump. If it checks out, ill boil it down to the spring fatiguing over time and in that case, i'm not too worried about it. If the flow test shows a poor result, Ill begin a search for a pump or a rebuild kit if available (price dependant). In the mean time, I've some jobs to do, so if it pumps, it digs. Im simply stating my thoughts here. If you see any flaw in my logic please point it out and correct me. Id rather be just dumb, not dumb and ignorant.
Yes, it switched sides, but it is not as bad as it was before. Still needs fixing though.
Bibendum. To my farmer brain your thinking seems sound. I like the idea of compensating for the bypass by adjusting the horsepower control. But let's see what Uffex thinks.
Good day Both the pumps regulators are connected as one alter one alter the other. From what I have been able to establish from a trusted source that the issue revolves around the valve plate porting. Not something we can play with only make an after fix - hence linking the main lines when you select high speed tracks. I am thinking on the lines that a simple cheap solenoid valve hooks the lines together when you select high speed tracking. What is your opinion? Kind regards Uffex
I thought about putting in a solenoid so I could control it, but first I'm just going to hook them together and see how it functions. I've ordered the fittings. I'll report back.
Thats great I dont think you will need anyting larger than 3/8"
Good day I have taken a look at the wiring schematic. I must admit it is a little confusing. The solenoid that controls the motor displacement according to the diagram is hooked up to s second safety switch. Can you straighten this out for me? What switch do you have in the cabin? Kind regards Uffex
That control lockout is the handle on the left that must be pushed down to operate the machine, like pretty much all excavators have. The high speed travel functions is a pedal that is held down and it actuates a hydraulic control valve.
Good day I must point out that hooking the main lines together at the pumps may have an adverse effect on the remaining circuits, to avoid this as much as possible will be a compromise. Making the connection to the two forward travel lines would give straight travel in the forward direction but not in reverse. This would be my suggestion, there would as to the best of my research little benefit in pump rebuild - replacement. If you get the correct track speed is a strong indication that the pump is giving the correct flow, pressure is simple to confirm. Kind regards Uffex
I'm still waiting on parts to couple these lines together. I ordered fittings for the main lines at the pump which won't fit the travel lines, so that's what I'll be trying first. I'll see if it affects the other operations of the machine too much. If I were to hook the travel lines together after the control valves, I would have to put a valve in the coupling that I could control from the operator seat. Because if that valve was open and I only moved one travel lever, the machine would respond by tracking straight. I wouldn't have independent control of the tracks in forward with the lines coupled. So I'm thinking if I am going to need to put in a valve that can be controlled from the cabin I might as well do it at the main pump lines. That way I can travel forward or reverse straight, and with the valve closed it won't change anything with the rest of the machine. Also, there's a lot more room to put the new hardware in near the pump than there is under the floor pan. I'll let you guys know how it goes once I get the parts.
Good day That's is a good plan, it's great you have a good understanding and know the pros & cons. Kind regards Uffex
Hey Bib. Did you ever flow test that pump? Any updates?
JR, I haven't had the chance no, have been working the machine. I did crank the pump up some more though. If you push enough material with it i imagine i can just about get it to stall, so i just go easy on it. So far it has dug 3 utility trenches and grubbed and levelled a yard. Not being able to use the blade on these little excavators to their full potential is quite a pain. In my opinion it really is what makes the smaller machines efficient. It looks like there are rebuild kits around for them. After talking to a few colleagues I think theres a good chance that the pumps can be freshend up by tearing them apart, removing the scratches on a flat lap and then lapping the two faces together. If the pistons / barrels are shot it needs a full rebuild, unless they are sleeved.
So this was an unexpected result. I hooked the pumps together where the lines exiting the pump, and I thought that would make it track straight but also have some changes to the digging controls in how they function together. Several things happened: First, you can't drive one track at a time with the pumps tied together. When the track control lever is in neutral, there is a passage for flow from the pump to get back to tank. When you push the lever forward, the path to tank is closed and oil is forced to the travel motor. With the pumps tied together, when I push the left travel control, the oil just all goes through the right control valve neutral passage, and vice versa. The only way to turn is to do one track forward and one reverse at the same time. When you push one lever only, absolutely nothing happens. Second was expected, but worse than I thought it would be. The digging functions are totally screwed up with the pumps tied together. Like the tracking, you must be doing 2 functions or nothing happens, and it's basically impossible to simultaneously control the curl and stick properly like we are all used to. And third, it did NOT track straight! It went left again. Recall it went left initially, so I swapped lines at the travel motors and it switched to the right, therefore I eliminated the travel motor as the cause. I also swapped lines between the directional valve and the swivel, and it switched again, tracking right, which eliminated the swivel as the cause. I thought it was the valve, but then swapped lines directly at the pump and found it again switched to the right, so we concluded it was the pump. (However, in this configuration, it didn't seem to be deviating right as much as it had in the original setup.) Tying the pumps together should provide equal pressure and flow to both control valves and therefore both travel motors, but it went left again. With any pump differences eliminated, that means the deviation I am seeing now is probably from the control valve, travel motor, or both. Essentially, the only way to really fix this from what I can tell would be to put in new components, which is not going to happen due to cost. Finally, I want to ask about what Bibendum did, turning up the horsepower control at the pump. I'd like to try that to compensate for internal leakage in the pumps, but I don't want to cause any damage. Obviously if the engine is straining noticeably then it's too high, but I have a feeling that might help my situation a bit too. What are the risks of turning that up? How would I determine that it was at a good level, or if it was too high?
Good day Screwing up the equipment was much as I would expect however I would expect the measure to straighten out the crab crawling. I would suggest the following lift each side of the track frame and measure how much pressure is required to drive each side as well as measure the rotational speed in both directions. Some detail has been missed. We need to go over this once more. Kind regards Uffex
I'm not sure it's worth more troubleshooting at this point, because I think I've definitively proven that there are multiple simultaneous problems. Correct me if I'm wrong: Given that when I change the pump connections the tracking changes from left to right, the pumps are obviously performing differently. Follow that with when I tie the pumps together eliminating any difference there, I am now tracking left again, which means the control valve and/or travel motor are contributing to the problem too. Recall that with the pumps reversed, it did not deviate to the right as bad as it had been deviating left. So the pump discrepancy on one side and the valve/motor on the other canceled each other out somewhat. I think that is the configuration I am going to leave it in. Agree with my thinking? The reality is that I would have to put in a new pump, new control valves and a new travel motor to truly fix the issue, and the problem just isn't bad enough to justify that level of cost. What do you think about adjusting the horsepower control of the pump? What should I check to make sure I do this properly? Cheers, Jon
So I tried adjusting the horsepower control. I checked the speed on tracking over 100 meters and then adjusted the control by 1/4 turn increments. After 4 adjustments I was 1 full turn in, and I had only improved my speed by 2 seconds, hardly any difference at all, and the tracking issue did not change. I'm reluctant to adjust it further because I'm not sure if it could cause harm, but the engine never sounds like it is straining at all. Until I can learn more, I just put it back where it was.
Good day Jon For a more pernament fix plumb the two forward main lines together with a solenoid valve. I will make some information for you. Kind regards Uffex
Good day Please see attached. Kind regards Uffex
JR, The way I look at it, if the pressure compensator is capable of being cranked “all the way up” then the pump must be designed to output that pressure / flow. I can’t imagine these pumps were designed for your machine only so the manufacturer has to give the end user the capability to match the pump to your prime mover. If you’re concerned with damaging anything, Id say as long as your system reliefs are set properly I figure that should provide you with the intended protection. You will however see an increase in machine function speed as I did. The only thing is, if there is a difference in flow between P1 and P2, increasing the pumps set point wouldn’t change your symptoms, you’d just have the same symptoms, but faster. Id say you could correct this by then adjusting the mechanical throw of the travel valve on the higher flow pressure line (choke it off so it restricts flow to the same flow rate as the bypassing pump to the slower travel motor) Or! You could take the pump off and rip it all apart, find the issue and determine if it can be repaired. Or completely prove me wrong! Then I don’t have to go through all that work myself! Either way, you’ll get her fixed. You’ve no choice at this point! haha I still haven’t flow tested my pumps, I’m onto building an equipment trailer. It’s on the list though
JR, https://www.parker.com/literature/Literature%20Files/hydraulicpump/training/Acrobat/Industrialtrainingtemplatebasics.pdf Good bit of information there if you’re curious. “Parker” is a fluid power equipment manufacturer. Basically all the hydraulic equipment in the facility that I work at is either Parker or Rexroth.
John I saw your video, why did you not swap the piston in the control valves ?
Good day folks Power regulation of the pumps for your machine appears to be linked, power from the motor is less at low revolutions, some excavation activities require low engine speeds. High levels of pump demands will load the motor, which may result in killing the engine. Kind regards Uffex
ProjectFarm101 has the same problem and just completed a video on it. he's pretty smart. Watch his issues and fixes here I think his is a 2002, but basically the same thing.
Good day That is a real professional video John I have said it before you have a real skill in making informative information. Back to straight track situation, what is possible if you hook a connection valve up in the line you used for test purpose - activate it with the high speed signal to the motors - this will mean when in high speed you get straight crawling in the forwards direction - you will need to switch down to low speed to have steering in the forwards direction. Kind regards Ufffex