Daewoo 130 LCV - extremely weak tracking

[Randy T]

The airation should affect the work of the whole system not just travel!

I agree, and the boom and arm are not springy like I would expect if they had some air in them.

Your suction side supposed to be pressurized ( pressure in the tank regulated by valve in the breather), so any leak in suction should come up as oil stain/leak on the suction pipes.

The tank stays pressurized for at least hours after shutting off the hoe and the suction hose and tubes are oil free.

All your return flow should enter below top oil level.

I confirmed that oil enters below oil level by viewing the fluid inside the tank, while running, through a cover I had removed.

Brass particles might be from piston shoes of the motor or pump. Check your suction - airation and piston shoes damage can come from suction restriction.

Maybe I am wrong, but I thought a tiny amount of super fine brass particles was normal? The particles I saw, it would probably take hundreds of them just to equal the size of a grain of sand. The suction strainer was rather clean, defiantly less than 5% restricted and suction tube and hose are not collapsed. I guessing that should rule out suction restriction.

After I put things on the hoe back together I worked it on a slope for about 45 minutes, all of the same symptoms eventually appeared as expected. One minute it easily climbs the slope (even at 1,200 RPM) the next minute it can just barely climb the slope and only with maximum assistance of pulling with the hoe arm. Running at lower RPMs delays the onset of the symptoms. The forceful resistance in the joysticks seems to only happen during forward tram or when attempting forward tram, and even when forward traveling down slope. It got dark on me today so I plan to do the IR thermometer testing tomorrow, as I don't yet have the other testing equipment. I believe once I can follow through with all of your testing advice, the problem(s) will be revealed.

I can't thank you all enough for all of your knowledge and assistance.

 

[TVA]

Yeah good IR thermometer should give you a location of bypass leakage, but I think you will be second guessing yourself until you see pressure drops on the gauges. Especially when you find out the prices, then you will start REALLY second guess!

Don’t forget to pull the covers off of the motors when taking the temperature readings.

 

[TVA]

Stiffness in joystick can be caused by leaking spool in main control valve, should be shown by spiking pilot pressure when monitoring with the gauge.

 

[Randy T]

Yeah good IR thermometer should give you a location of bypass leakage, but I think you will be second guessing yourself until you see pressure drops on the gauges. Especially when you find out the prices, then you will start REALLY second guess!

Don’t forget to pull the covers off of the motors when taking the temperature readings.

Oh I already know $3,675.00 per final drive motor and $5,036.25 plus $350 shipping for the pump. At those prices I will just have to contend with running it for about 45 minutes per day. Thanks, I was wandering if I need to pull off the motor covers or just check the line temps, good know.

 

[Randy T]

Stiffness in joystick can be caused by leaking spool in main control valve, should be shown by spiking pilot pressure when monitoring with the gauge.

What might involved in repairing a leaking spool? Possibly just need new seal or new valve body. I know virtually nothing about the inner parts of pilot controlled valve bodies. Still sourcing replacement set of manuals (shop, parts and operations).

 

[TVA]

Oh I already know $3,675.00 per final drive motor and $5,036.25 plus $350 shipping for the pump. At those prices I will just have to contend with running it for about 45 minutes per day. Thanks, I was wandering if I need to pull off the motor covers or just check the line temps, good know.

If your other functions is working good then pump is not a problem.

 

[TVA]

What might involved in repairing a leaking spool? Possibly just need new seal or new valve body. I know virtually nothing about the inner parts of pilot controlled valve bodies. Still sourcing replacement set of manuals (shop, parts and operations).

You need to run tests first, could be a speed changing spool in the motor, have a patience!

 

[uffex]

Good day
A couple of points that may be of interest the self pressurising valve on the tank check it out, it should be able to vent air after a few strokes of the cylinders, the machine has a back pressure valve on the return line, this prevents cavitation somewhat but defective it could contribute to air entering the system.
It is of low pressure 3-4 bars (40-55 p.s.i) with fluid at working tempreture.
I would endorse TVA comment check out the suction lines carefully a block or partially blocked strainer filter will encourage air to be drawn in.
Kind regards
Uffex

 

[Randy T]

It is of low pressure 3-4 bars (40-55 p.s.i) with fluid at working tempreture.
I would endorse TVA comment check out the suction lines carefully a block or partially blocked strainer filter will encourage air to be drawn in.

Thanks, the tank does build and hold pressure, not sure how much pressure, also I don't know how much pressure the manual calls for (still working on sourcing replacement manuals) but I will look around on the cap to see if it states a pressure rating. The suction strainer had well less than 5% contaminate blockage, but it is all clean now. I will be running it again today and will check for bubbles in the tank fluid afterwards.

 

[John C.]

Tank pressure is usually one atmosphere or 14.6 PSI. Cycle times for boom, arm and bucket are usually all you need to check pump output. Normal time for boom up on excavators your size is between 4 and 5.5 seconds. The center swivel is the usual cause of weak travel in one side and sometimes on both sides. The usual failure progression is that the machine will not track straight. I have also seen where the problem shifts tracks when you swing the house to the other direction. A stiffening of the pilot control handles is usually a clue that main pressure to the travel motors is getting into the high speed travel control circuit ,which is pilot pressure, at the swivel. You usually see the issue when you travel and operate the implements at the same time. You can check that by capping the hoses for high speed travel at the swivel and run the machine travel at the same time as an implement. If you get a squirt of oil from the fitting you can be sure you need to repack a swivel. I would waste the time or the oil to do that, at this point it is easier to just pull the swivel. I haven't worked on a Daewoo so can't tell you what it takes to remove and reseal a swivel but all other manufacturer's machines of that size that I have worked on took less that six hours to complete. Seals for a swivel are usually less than a couple of hundred bucks. Travel motors, valves and pumps will run many thousands.

There is a lot of information being presented here that is for the most part good for people that do this stuff all the time. However, it is just muddying up the problem. Work from least expensive first and remember "KISS", keep it simple stupid!

 

[TVA]

Tank pressure is usually one atmosphere or 14.6 PSI. Cycle times for boom, arm and bucket are usually all you need to check pump output. Normal time for boom up on excavators your size is between 4 and 5.5 seconds. The center swivel is the usual cause of weak travel in one side and sometimes on both sides. The usual failure progression is that the machine will not track straight. I have also seen where the problem shifts tracks when you swing the house to the other direction. A stiffening of the pilot control handles is usually a clue that main pressure to the travel motors is getting into the high speed travel control circuit ,which is pilot pressure, at the swivel. You usually see the issue when you travel and operate the implements at the same time. You can check that by capping the hoses for high speed travel at the swivel and run the machine travel at the same time as an implement. If you get a squirt of oil from the fitting you can be sure you need to repack a swivel. I would waste the time or the oil to do that, at this point it is easier to just pull the swivel. I haven't worked on a Daewoo so can't tell you what it takes to remove and reseal a swivel but all other manufacturer's machines of that size that I have worked on took less that six hours to complete. Seals for a swivel are usually less than a couple of hundred bucks. Travel motors, valves and pumps will run many thousands.

There is a lot of information being presented here that is for the most part good for people that do this stuff all the time. However, it is just muddying up the problem. Work from least expensive first and remember "KISS", keep it simple stupid!

Amen to that! If your hours is close to 7000/8000 it’s recommended that you repack the swivel anyway. Also check your swing bearing for slop.

 

[John C.]

Where are you getting those hours from? I've worked on most all the major brands and have never seen that recommendation in any published manufacturer's recommendations or specifications.

 

[TVA]

Where are you getting those hours from? I've worked on most all the major brands and have never seen that recommendation in any published manufacturer's recommendations or specifications.

I didn’t say it was recommended in the literature. Just observation ( as equipment I work on is all older machines) and also talking to other owners and mechanics, it seems like that’s the hours that seals in swivel start to fail. Provided, of course, that machine was operated normally, not like the owner of one of shipyard who build the small tug boats - he liked to pull the boats ashore by using the swing of either his excavator ( I think it was JD 922 ) or Grove crane.

 

[TVA]

Where are you getting those hours from? I've worked on most all the major brands and have never seen that recommendation in any published manufacturer's recommendations or specifications.

But I admit that I used word “recommended” in the wrong context!
I apologize!

 

[John C.]

I didn’t say it was recommended in the literature. Just observation ( as equipment I work on is all older machines) and also talking to other owners and mechanics, it seems like that’s the hours that seals in swivel start to fail. Provided, of course, that machine was operated normally, not like the owner of one of shipyard who build the small tug boats - he liked to pull the boats ashore by using the swing of either his excavator ( I think it was JD 922 ) or Grove crane.

So based on two machines and your vast years of experience you deem it advisable to state as a general rule that swivel packing fails in that range of hours? Is that on all machines with a swivel? You mention a JD922 of which I'm not familiar with as an excavator and also a Grove crane which is an entirely different machine and type of swivel. You then make a statement about a machine operated "normally" and then imply that using the swing function on an excavator to pull a boat is somehow harmful to the operation of the swivel. What is it about swinging the house on an excavator that would cause the swivel seals to fail? What is the usual process of swivel seals failing?

 

[TVA]

So based on two machines and your vast years of experience you deem it advisable to state as a general rule that swivel packing fails in that range of hours? Is that on all machines with a swivel? You mention a JD922 of which I'm not familiar with as an excavator and also a Grove crane which is an entirely different machine and type of swivel. You then make a statement about a machine operated "normally" and then imply that using the swing function on an excavator to pull a boat is somehow harmful to the operation of the swivel. What is it about swinging the house on an excavator that would cause the swivel seals to fail? What is the usual process of swivel seals failing?

Oh! Forgive me, o Greatest of all technicians ever lived John C., for daring to comment after you showed up at the thread on your “high horse”!
No! hours doesn’t matter! Improper use of equipment doesn’t matter! Broken swing gears doesn’t matter! Ruined swing bearings have no impact on swivel seals! No, no, no!!’
Using swivel of the excavator or a crane to drag a tug boat on the ground and breaking swing gear on the swing motor it does not impact machine at all! Please, please, please forgive me, o greatest Technician ever born!!!
Yes, yes, yes, it’s all in my sick, twisted, and unexperinced mind! I made all this up! Please, please, forgive me o Greatest?!?!

I’ll just crawl in my little hole and shut up! What was I thinking? Still commenting on the thread after John C. blessed us by stooping down to comment on this thread!!! Stupid, stupid me!!! I’m lowliest if lowest imposters! Shame on me!!! Shame on me!!! Shame on me!!!

 

[Randy T]

Today I worked the hoe until the symptoms were fully apparent, parked it for 1 hour, removed tram motor covers, took temperature readings at the tram motors, pump, control valve, center pivot, started it up, put the RPMs to around 2100, pulled the left track lever to full reverse and kept it there for the next ten minutes while checking temps. The pump, control valve, center pivot got up to around 130F and the tram motor and the lines connected to it never got above 105F and the track never rotated even an inch during those ten minutes. I took video while checking temperatures. That's all I have time for tonight, got work tomorrow. TVA, with regard to your above post to John C. I hope you are not actually dissuaded from posting here, I highly value your input.

 

[Randy T]

I am just an operator but these people have this opinion. http://info.texasfinaldrive.com/shop-talk-blog/swivel-joint-or-travel-motor " It seems that after about 5,000 hours the swivel joint seals on most machines tend to start leaking."

 

[John Tobin]

BACK IN TROUBLE AGAIN
Hi All
I thought I had my tracking issue resolved but it is back and worse then before. After changing all oils and filters everywhere in the machine she appeared to be fine and climbed a steep bank no problem. However I then took out a link on each track and tightened up my tracks (this job was a bit of a nightmare to do, as we ran into a few issues and I did this with the mechanic as his helper for the day) leaving the correct gap between track and undercarriage according to the manual
I took the machine away worked it for a couple of hours and one of the idlers appears to have seized up solid and is currently lodged up against the back of the yoke. I am wondering if this issue was also part of my problem all along and that tightening up the track has now highlighted the problem. Uffex did say to check filters first, then idlers then hydraulics so in my case this advice is spot on
Anyway I have an idler ordered, but does anyone have any advice on removing this on my machine
Thanks again John

 

[uffex]

Good day John
I kind off hoped your troubles were over, here is the information after the chain is split just pull the idler wheel from the guide.
Kind regards
Uffex