Hey all this is my first post . Just bought my first excavator I'v ever had ,for our rough 40ac block Was cheap ex-quarry machine with a lot of hours .Anyway the drive motors in the tracks are very slow to respond and go very slowly and cannt hardly turn -- only really go when both tracks are going .The hydraulics in the arm and bucket have plenty of power though . Someone said it could be a sticking or partly opening valve.It still slews and the stick still operates when walking so it seems not all the hydraulic pressure is going to the tracks . If anyone has got any ideas I'd be most grateful . Thanks Mat
Mat: There's a good chance the problem or at least part of the problem is located in the swivel joint. There are a series of rings on a stationary shaft that seal to the inside of a rotating cylinder. It will be located in the very center of the machine. This is what allows the oil to pass from the upper structure to the lower. After many hrs. they wear out and oil bypasses back to the reservior or to another circuit. I have a Cat that had roughly the same trouble. Feel free to contact me directly if you have any other questions. Steve
Thanks Steve , sounds like quite a difficult major job. Guess ill tolerate the slow walk speed as long as it keeps moving.
Since you state the problem is on both tracks the swivel would also be my guess. Before you pull your swivel I would suggest pulling the suction strainer out of the hydrualic tank and checking for packing in there. The stuff is usually a white plastic and it will be in little bits looking like pebbles in the screen. The swivel is real simple to repack. It's basically unhooking the hoses on the barrel and capping them, pulling four bolts out of the top cap and then the inside snap ring and spacer ring under that. Pull the pin on the rotation stay rod and then the barrel then lifts off the center section. The sealing rings are on the inside of the barrel and can be a pain to get into place. If the barrel lifts off real easy then that was most likely your problem. If you can't move it by hand its probably OK. When you reinstall the barrel you will either have to jack it down with something or use a hammer and block of wood. It goes back on that tight. Komatsu is the only excavator manufacturer that uses this type of swivel. All the other manufacturers you have to remove the entire unit to repack it. Good Luck!
thanks a lot John. Doesnt sound too hard a job to tackle.Guess it will stop walking completely eventually then I'll pull it apart .Just working close to the house and shed anyway. thanks again Mat
i had what sounds like the same problem only with one track though, but we check the oil in drive motor and it very low in the track that didn't have any power. after we filled it up its back to normal power.
I have a pc-60 when i went to check the oil level in the travel motors it was way over the oil level so i drained and it drained all the oil out of the hydralic resivoir is the finals oging or the swivel joint?
going
hey matt i have the same problem. I run a pc300 with a labounty shear and it has the same problem. I tear out alot of old pipe racks and tanks in the mountains and some things i just cant get to because i cant climb or get to some locations because i have no power in my tracks hardly. mine is exactly the way you described that yours was if both tracks are going its a little better but not much and if i want to turn i have to jump turn cuz i just cant spin the tracks..Ive kinda been hopin the ol girl would just take her last breath haha so i could get a knew one or at least put a hammer on her and use it to break concrete or something.
Suppose the oil will run out soon and we can go back to using oxen --- lot less headaches.
Sounds like output shaft seals are shot on the drive motors ,and instead of the casedrain returning to the hyd tank it is leaking into the planitary.Time for a drive motor rebuild before they pile and cotaminate your hyd. system.
i have a case 9020b and i am having the same slow trouble with my drive motors. i checked the oil in them and it's very black and smells burnt.
Welcome to Heavy Equipment Forums superdaddydave! :drinkup
Hi guys. Was working on a PC200-6 on the weekend. Showing these exact symptoms. Slow travel speed on both sides. Still able to walk in a straight line but struggling when trying to turn or when put under any load. Pulled apart the swivel valve and found seals to have totally disintegrated. Machine has done big hours at 16000 but it looks as though the incorrect oil has been used leading to the problem. Will be finishing the job this week so will report back.
Probably not an oil problem. That just how they fail. When you put the new seals on it will be very tight to push the barrel back on. I've used a piece of lumber and a hammer more than once. One time in Alaska I was in the middle of a road trying to get the barrel back on and didn't have a big hammer. A guy trying to get by us in a Volkswagen Beetle had one of those scissors jack that we were able to rig against the boom and push the thing back together. Fifteen minutes later the machine was running and everyone was pretty pleased. Good Luck
I have an issue with my travel aswell. Relief pressure is only achieved on left side track 320ish. the right side only reaches 98 bar. What could be the issue?
We had this issue with all 3 of our komatsu excavators; pc130-6, pc120-3, pc160-7. Thanks for the idea on how to fix it
Is there a way to save treads for future references?
Where is the swivel valve located on the Komatsu PC120-6 ? Thanks for any info.
Define "swivel valve"..... Do you mean the rotary swivel in the centre of the machine that takes hydraulic oil down to the track drive motors.? But that's not a valve.
Thanks Nige ,Yes that's what I incorrectly referred to as a valve. In your opinion could this affect the turning ability of an excavator? That is all other functions are snappy but the machine just won't or is very sluggish turning . Mark
When you say “turning” do you mean swinging the upper frame or changing the direction of travel using the tracks.?
Nige changing the direction of travel. All good going straight fwd and aft but difficulty changing direction
In that case I would suggest that you carefully read Post #4 on Page 1 by @John C. and "have at 'er".
Thanks Nige for your help
Thanks Nige I'll have a look at the rotary Swivel