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

[Nige]

By "keeper plate", do you mean the L shaped bracket that's there to stop the bleeder from coming off if the nut is over loosened?

Yes.

It looks like the outer nut is the one the manual refers to, and is to be loosened no more than one turn, to relieve the grease from the cylinder. The L bracket and both nuts come off to remove the whole assembly for inspection? Can't the Zerk itself be removed without taking it all apart first? Or is that a safety issue?

First crack the large nut (bleeder) a turn to relieve the grease pressure. When the grease stops coming out there should be no pressure left in the track tensioner. You will find that the outer and inner nuts are all one assembly. A groove has been machined into it. This is where the keeper plate fits to prevent the bleeder being unscrewed more than the specified one turn while under pressure. Once you have released the grease pressure the valve assembly can be safely removed but obviously you need to be careful. If there is a location on the front end of the track frame where you can get some wood blocks or wedges in behind the idler wheel so much the better. That will prevent the idler from retracting and avoid nasty surprises.

Here's the deal. It appears as though the grease zerk is a modification. Usually the whole bleeder assembly is one piece and the zerk is part of that, not separate. The clue is that the zerk is normally straight (like the one on the other side), not 90-degree. John C mentioned that in his opinion the assembly has been modified by drilling and tapping a thread for a replacement zerk. I bet if you clean the other side you'll find that the zerk is part of the larger assembly and not a separate item.

So the deal is that deeper inside the bleeder assembly is a ball-type check valve designed to prevent the grease pressure being held by only the little ball in the head of the zerk. The thought is that ball inside is stuck/seized and that's why you can't get grease into it. To get at the check valve you're going to need the whole bleeder assembly removed from the machine.

 

[Bluox]

All you have to do is loosen the fitting the grease fitting is in and screw it open till it hits the keeper plate .
This will allow grease in adjuster to exit.
You may have to push on the idler to get it to go in ,this will relieve the track.
This has nothing to do with the recoil spring.
When you put the new track on close the fitting and add grease till your track adjustment is right.
Bob

 

[Mark A Weiss]

Thank you for all of the suggestions and hints on unsticking that Zerk.

Now what remains is to find a track. I have my neighbor, who is visiting PA this week, looking for one, but no luck so far. My own efforts to find a used but still serviceable track have been fruitless so far as well.

The ebay seller with the pair of tracks has not responded to my question yet.

In the meantime, I have a very expensive yard ornament until I can resolve this.

 

[Mark A Weiss]

I just heard back from Rubber Tracks of America and they counteroffers with about $3350 cost for a new pair of tracks. Ship time 3-4 days they said. Paid with Paypal credit, because I'm all out of savings.

I did not realize these tracks weigh 908lbs each! Getting them onto the excavator will take some doing. Especially if I can't get those grease Zerks released.

 

[Welder Dave]

You need to inspect other parts of the undercarriage too. Generally you need new sprockets but maybe not with rubber tracks? What are the rollers like, etc.? I sure hope you don't put yourself in a bad financial situation because of this machine.

 

[heymccall]

I buy singles all the time.
I know you've got them coming, but, what size are they?

 

[skyking1]

You need to inspect other parts of the undercarriage too. Generally you need new sprockets but maybe not with rubber tracks? What are the rollers like, etc.? I sure hope you don't put yourself in a bad financial situation because of this machine.

rarely do you need idlers or sprockets. The rollers can get beat, and I have replaced a top roller.

 

[Mark A Weiss]

I buy singles all the time.
I know you've got them coming, but, what size are they?

450x83. 5kx74. I asked if they fit the PC60-7 and they confirmed it does.

I still feel like I'm making a gamble here, but I see no other option other than taking a huge loss on the machine.

But 900lbs a piece. How the heck will I get those onto the machine? I've watched a video showing how to change tracks on a mini, but nothing this large. Also, I'm parked in a dirt area, lots of sand and small rocks. Wish I were on a paved area, but there's no pavement anywhere around here.

As far as the rollers and such, I am not sure what to look for in terms of inspection.

 

[Welder Dave]

If you can get close enough, you can use the machine to help move the tracks. If it still moves smooth an area to replace the tracks. New tracks should help if you decide to sell it in a couple years.

 

[Mark A Weiss]

If you can get close enough, you can use the machine to help move the tracks. If it still moves smooth an area to replace the tracks. New tracks should help if you decide to sell it in a couple years.

I'm pretty sure I can use the bucket and a strong set of ropes to move the tracks close to the machine, but how to get the last couple of feet and get the tracks onto the sprocket and idler becomes the looming question.
I'm sure new tracks will help with the resale. I'm hoping nothing else goes wrong in the meantime.
I don't have much of what you would call "smooth ground" here. The back yard is swampy. The driveways are of dirt and 1" crushed stone that has been churned up by driving the machine over it. Maybe I could buy some plywood (at $114 a sheet) and lay it down along side the machine and then slide it under the area where the track goes; that might make it less messy. Any way I look at this, it's going to be a struggle. I'm open to tips and suggestions from those with experience on changing midi excavator tracks.

 

[John C.]

You can put on rubber bands anywhere. The bit issue is getting the front idlers all the way back in the track frames. Release the grease fitting and use the bucket to push the idler all the way into the track frame. If it is out at the end and won't move in, you will need to remove the adjuster and spring assemble and repair or replace it. If it will move in, the you use the boom and bucket to get the track close. Pick up the side where you are going to install the track and put blocks under the machine to hold the bottom rollers about a foot off the ground. Then you can again use the boom, stick and bucket to work the track on. Get the band over the sprocket first and work the track onto the top rollers and work forward to the idler. You may need a bar or two and I have used a chain or wire rope sling to pull the band over the front idler. They can be a fight but it isn't that big a deal after you have done your first one.

 

[Mark A Weiss]

Thanks for describing the process John. The part about using the bucket to push in the idler is particularly helpful.
Raising that side of the machine on blocks might be a sticky area, due to the soft ground, stuff sinks right in. Maybe blocks and 2x12s to spread out the weight.
I hope there's nothing preventing the idler from moving. That cylinder assembly is scary. I read there's a spring in there that is under tons of compression force. Not something I want to mess with.

In the meantime, I've been spraying WD40 on those Zerks and surrounding components daily, to have hope that it will loosen.
BTW, both Zerks are right angle. The one on the right side of the machine is actually loose! I can turn it by hand. Makes sense that they'd have a right angle otherwise you couldn't get a grease gun fitting over it due to the interference of the surrounding structure.

 

[Mark A Weiss]

Rubber Tracks of America just refunded my payment for purchase of new rubber tracks.


Rubber Tracks of America
Order #6536
Your order has been canceled
Order #6536 was canceled because we did not have enough stock to fulfill your order and your payment has been refunded .

I just checked the link where I bought the tracks and they are still for sale, but about $1000 more than they were priced at yesterday!

Now I'm back to square one.

 

[Mark A Weiss]

This place has a more reasonable rate. But the track specified for my model has a different track pitch. 76 instead of 83.

https://monstertires.com/shop/komatsu-pc60-7/

 

[Welder Dave]

Rubber Tracks of America just refunded my payment for purchase of new rubber tracks.


Rubber Tracks of America
Order #6536
Your order has been canceled
Order #6536 was canceled because we did not have enough stock to fulfill your order and your payment has been refunded .

I just checked the link where I bought the tracks and they are still for sale, but about $1000 more than they were priced at yesterday!

Now I'm back to square one.

Call them and see what the %$#@! is going on. If they only have 1 track ask how long for the 2nd one. They shouldn't advertise what they don't have and even if you have to wait a bit, should honour the price they advertised. The transaction was all but completed. I think upping the price now, after the fact, is false advertising.

 

[Mark A Weiss]

Found another place with a decent price. Had to apply for their Affirm credit line because they don't take Paypal. They said shipping takes a few days. I hope!

 

[Mark A Weiss]

Call them and see what the %$#@! is going on. If they only have 1 track ask how long for the 2nd one. They shouldn't advertise what they don't have and even if you have to wait a bit, should honour the price they advertised. The transaction was all but completed. I think upping the price now, after the fact, is false advertising.

I totally agree and am steamed about it. I gave them my frank honest opinion of their policy and they simply said they don't have them in stock and the next container shipment is at higher prices. Honor doesn't mean anything to these people. I reported them to the authorities, not that it will do any good.

Hopefully this other vendor won't screw around like that. I'm REALLY starting to regret my decision to buy this machine. I should have rented one for a month, probably would have been cheaper.

 

[Welder Dave]

It might be worth it if new tracks give you a fully useable machine. It is nice having a machine available right when you need it. It's a good lesson for the next time you want purchase something you could use rather than something you must have.

 

[John C.]

Where do you figure that someone's price can't change? Did you read the fine print in the sales receipt? You can find all kinds of posts on this forum stating that parts availability is spotty at best and you have an older machine that is likely gray market. You are just going to have to do the best that you can. It's Business!

 

[Welder Dave]

I never said prices can't change. Changing them after they've been quoted and money has been sent doesn't fly with anyone. Some would consider it false advertising or at least bad business practice. Has nothing to do if it's a gray market machine. The seller had already confirmed they were the proper tracks. If they didn't have stock and the price could change, they should have told him then. $1000 higher price after bating a customer is a lot!