Komat'su PC60-7 --Just Purchased Used--Some Questions

[Mark A Weiss]

Just got delivered on Monday, a Komat'su PC60-7 excavator with 6100 hours on the clock.

Works well overall, engine sounds very nice, hydraulics seem to be quick and responsive.

Couple of issues:

Only have one key. Not comfortable not having a backup key. And this key is worn. Hard to turn the key in the ignition. Can't get it into the preheat mode at all. Went to a bunch of places that duplicate keys and they all said this key is not in machine's program database. Where do you get additional keys made? I noticed that Amazon sells keys, but then that raises the question of how to get the key that matches your machine's ignition tumblers?

Second issue: Machine works okay for the most part, but it seems like the left track has less power than the right track. If I need to turn the machine in a tight space where there's little room to do a jump turn, I need to turn the tracks in opposite directions. The right track runs, but the left doesn't unless I push the right track lever a bit in the same direction as the left. Going in straight lines is no problem.

Third issue noticed today: Oil leaking from left side of engine compartment. Oil pooled on floor of engine compartment near the PPC Shuttle Valve. Didn't see any obvious leaks there. But oil dripped onto my left track and there's a trail of oil on the driveway. This after using the excavator to push over a small young tree (about 3-4" trunk dia) with the boom extended and the bucket and arm extended and just driving the tracks forward a little at a time. I'd estimate the contact point was about 10' up the tree trunk.
I was not aware of any oil leak prior to that.
Inspecting the engine compartment, I see no visible leaks. I even tried starting the engine and operating one function at a time and then looking to see if any fresh fluids had sprayed out. Nothing found. Wondering if there's some relief valve that momentarily opened due to an overload and dumped about a quart of fluid?

 

[John Canfield]

When my auction Komatsu D39 dozer was delivered the driver said he didn't have the key but one that would probably work. And it did - mostly. I got the real key from a Komatsu dealer.

 

[Mark A Weiss]

Thanks for the info about that key. It seems there is like a "master" key that works across multiple machines. Scary.

I think I have isolated my hydraulic leak at least by function. When I push the right travel stick forward, there's an audible hissing noise. There's a lot of oil leaking after forward travel. Pretty much stops if the machine is stationary. Now I need to isolate which line is failing. Likely it's a split in the hose somewhere. Time to hit the service manual and do some reading.

 

[John C.]

The master key is usually a 787 key if I recall right.

There are pilot lines under the travel pedals that go back to a manifold block with a bunch of shuttle valves and pressure switches. I would guess the leak is somewhere between the pedals and the manifold block. You can pull off the plates that are mounted to the bottom of the house in those areas to inspect those hoses.

Travel power has a few different causes but get the leak taken care of first before we give you more things to worry over.

 

[Mark A Weiss]

Thank you for the key info. I'll research it some more and see if I can find it.

Would that manifold block be the PPC Shuttle Valve, as indicated in the manual's diagram? It's possible the leak is further forward and spraying back toward the PPC, making it look like it's coming from there.

Are the pilot lines steel or rubber hoses? Maybe if steel, they are rusting out.

The location and access look like they will be a problem (I have a bad back). Any suggestions to make gaining access easier? I was thinking of parking it on solid fill and digging out a 2' trench then parking the machine over it like a service pit. Not too deep so the walls have a collapse hazard, but enough to give me room to work under there.

I'm going to go buy a few gallons of Tractor Fluid today so that I can replace the lost fluid. I use that stuff on my snow plow with good results and it's cheap compared to the stuff the manufacturers sell.

 

[Mark A Weiss]

So there are a couple of small plates underneath the house, but they don't look large enough to provide adequate access to reach all the ends of the lines.
The plate shown in the first photo is about 11" square.
The second photo shows the area where the oil runs out through the weep holes.
The third is near the front of the house.
Am not sure how one would access these pilot lines.

 

[Tinkerer]

$25.99 for the switch and 2 keys.

https://www.ebay.com/sch/i.html?_fr...&_odkw=komatsu++PC60-7+igbNITI+keys&_osacat=0

 

[John C.]

Any AW hydraulic hydraulic fluid will work. Tractor hydraulic fluid might be a lot more expensive than AW46 from a local distributor.

The plates are what you have to work with. The manifold would be where the PPC shuttles are located.

 

[Mark A Weiss]

I picked up a 5 gal bucket of AW64 for $47.99 at AutoZone. Added it to the main hydraulic tank. Are there less expensive sources for this fluid?
I also put another 10 gallons of diesel in the fuel tank. It seems like a bottomless pit, because 2 days ago I put in 10 gallons and it barely raised the level in the tank. Looks to be 20" below the surface, but fuel gauge says about 90% full. After adding 10 gals, gauge shows full, but there's lots of room in the tank.
My arm can't reach in there. Unless the 11" plate is right next to the pilot lines. Do they go into the manifold at that location? I figure the access panel must make it possible to change out lines.
Do I need any special wrenches to replace the lines? Are these lines flexible or rigid steel lines?
I may try to remove that plate and have a look in there. Probably best to turn the house 90° as it's over the tracks right now. I presume the large metal plate under the front of the house where the travel pedals are also has to come off? It's hard to tell from the drawings in the manual, unless I'm looking at the wrong drawings.

 

[uffex]

Good day
If you need help trouble shooting crawler issues we have complete information a little heavy to post here but you can view or download from the following go excatech.org > Library > common defects > weak crawlers.
Finding leaks is often easier with a helper operator and using a piece of cardboard in those awkward to see place's.
Kind regards
Uffex

 

[Vetech63]

Are there less expensive sources for this fluid?

Dont get anything cheaper. Its crap oil.

I also put another 10 gallons of diesel in the fuel tank. It seems like a bottomless pit, because 2 days ago I put in 10 gallons and it barely raised the level in the tank. Looks to be 20" below the surface, but fuel gauge says about 90% full. After adding 10 gals, gauge shows full, but there's lots of room in the tank.

Your fuel sender is probably off, Its a common problem.

My arm can't reach in there. Unless the 11" plate is right next to the pilot lines. Do they go into the manifold at that location? I figure the access panel must make it possible to change out lines.

Welcome to the world of mini's! They pack 8lbs. of crap in a 5lb. box. The access plates are there for "access" to some things, but in most cases.......your arm, wrist, and fingers will need to bend and twist in un-natural directions while your back and hips twist the opposite direction. Its fun as Hell!

Do I need any special wrenches to replace the lines?

In some cases yes. The access to each hose may be different, and you may very well need to remove multiple lines to actually get at the one you really want.

Are these lines flexible or rigid steel lines?

Could be either or depending on the manufacturer, model, location of components,..a multitude of variations.

Probably best to turn the house 90° as it's over the tracks right now.

Correct! Unless your a skinny elf you wont reach anything.

I presume the large metal plate under the front of the house where the travel pedals are also has to come off?

Only if you are replacing/repairing something that runs under it.

You will need to do some stretches before you start. Here is what may work to help you prepare for this challenge.
Lay in the floor of your living room. Have your wife/gf attempt to bend every joint in your body the opposite direction until it hurts like a mofo. While this is being done on your arms, have her take a wire brush and scrape the **** out of your forearms while also poking your fingers with a few needles. After that have her pin your upper body above your waist to the floor where your shoulders are flat, then have her twist you at the waist until your kneecaps are touching the floor also. Make sure she does this in both directions while pushing on your lungs to restrict your breathing. Once this is all done......your ready to tackle this!

 

[Tinkerer]

You will need to do some stretches before you start. Here is what may work to help you prepare for this challenge.
Lay in the floor of your living room. Have your wife/gf attempt to bend every joint in your body the opposite direction until it hurts like a mofo. While this is being done on your arms, have her take a wire brush and scrape the **** out of your forearms while also poking your fingers with a few needles. After that have her pin your upper body above your waist to the floor where your shoulders are flat, then have her twist you at the waist until your kneecaps are touching the floor also. Make sure she does this in both directions while pushing on your lungs to restrict your breathing. Once this is all done......your ready to tackle this!

OMGosh !!
Awesome !!

 

[Mark A Weiss]

Thanks for the tip Uffex.
Vetech63, with my back injury, simply crawling under the wife's SUV to do a brake job left me in bad condition for almost 2 weeks. This sounds like a job best left to a young and healthy person.
It's raining hard today, but if it lets up later and the mud isn't too deep, I may try to take the plate at the middle of the house off and have a look in there. I prepped the bolts with WD-40 last night, so hopefully they are not going to be too difficult to remove.
If the lines go up to the track pedals, it is likely the larger panel underneath that area will need to come off to access connections.
This is my first excavator. I'm retired. What a first problem to deal with and only a few days after I bought it.

 

[Mark A Weiss]

I noticed that on Bobcat excavators, the floor panels can be removed, giving access to hydraulic lines under the floor. Am I correct to assume there is no such access on the Komatsu PC60?

I've just been studying this diagram and it looks like many of those lines run continuously to the control valve. It's not a short run to a manifold block like I first thought.

 

[Mark A Weiss]

Can anyone advise as to how delicate the travel mechanism is? The seller is telling me that I may have burst the lines by trying to push dirt that was not broken up first. The blade looks like it's meant to cut through tough ground, though I've always been gentle and cautious with the machine.

 

[Vetech63]

Can anyone advise as to how delicate the travel mechanism is?

I'm not sure what your asking here.

The seller is telling me that I may have burst the lines by trying to push dirt that was not broken up first. The blade looks like it's meant to cut through tough ground, though I've always been gentle and cautious with the machine

Your not going to bust pilot lines like that. The blade on a excavator really isn't to be used like a dozer. It more for backfilling ditch lines than anything else.

 

[Mark A Weiss]

More specifically, if you're pushing against something that causes the tracks to slip on loose dirt, is that putting too much strain on the travel motors and associated lines?

Was it a mistake to use the travel motors with the boom extended to push over a small 4" dia maple tree?

What would cause a pilot line to burst other than age?

 

[Vetech63]

More specifically, if you're pushing against something that causes the tracks to slip on loose dirt, is that putting too much strain on the travel motors and associated lines?

No. The system is designed with a high pressure relief that is set to a factory spec. If you were to overload the track drive, they would basically run over relief pressure and stall.

Was it a mistake to use the travel motors with the boom extended to push over a small 4" dia maple tree?

In my opinion, not really. Its unlikely you would damage the system with all the hydraulic safeties it has (circuit reliefs, load checks, main reliefs.....etc.) You CAN damage something the system if someone has gone and screwed with the relief settings and have then too high.

What would cause a pilot line to burst other than age?

Age and abrasions is the most common. The pilot system has a pressure reducing valve I believe that regulates the pilot system pressure to a set value. Using the wrong hose rating on the system can cause a hose failure also.

 

[Mark A Weiss]

That makes sense. I would think these safeties are built in otherwise service mechanics would be overloaded with repairs and unhappy customers.

I removed the 11" square plate that is about even with the operator's seat under the house. Didn't see any evidence of hydraulic fluid at that spot. I did find a lot of muck in the form of earth or possibly decayed leaves, acorns and pine needles in that space. There's a manifold (maybe the blade control valve) there with somewhat rusty connections but nothing wet from leaks. I put WD-40 on all the metal parts to retard the rust.

I suspect the leak is further back, somewhere between this inspection port and the PPC shuttle valve. Will have to get someone to gently operate the right travel stick while I look in the engine compartment. I have no clue how they installed those lines in there. No human arm can reach that shuttle valve!

 

[John C.]

Welcome to our world.

You are on the right track thinking about getting someone to operate things while you look. Make sure to wear eye protection and don't stick your fingers down in that rat's nest while a function is pressurized.