Komatsu mini questions and intro..

[Elbonk]

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Howdy and greetings from Oregon. I recently purchased a mini-ex, a Komatsu PC30-R Avance, ser. # 10651 and it's a gray market unit with 2900 hours. I am just a homeowner with some property that needs a lot of work.. My little JD 770 4WD tractor just doesn't cut it with stumps and rocks. It has a solid motor-smooth and a bit of smoke on a cold start and good hydraulics but one of the tracks has tear/stretch that the previous owner either didn't know about or just kind of didn't mention so it hops on the drive wheel.
It also has a fair amount of slop in the pins and the one of most concern to me is the vertical pin that allows the boom to pivot as part of the offset boom feature. It has been plummed for a thumb but there is no pressure relief for the thumb and two cylinders later the owner quit replacing them.
I have the thumb but need to figure out the correct size/ capacity/length and then figure out how to plumb the pressure relief kit/apparatus.
Komatsu has already come through for me on sourcing parts and the top idler I replaced with an aftermarket and komatsu beat them price wise, unfortunately I had already purchased one. They also had manuals for a similar PC 30- at least he thought it should be close. At $4500 for the boom kit I am going to check into other possibilities, however...
My questions are as follows:

1) Does anyone have brands they recommend using or avoiding on rubber tracks? Les Schwab here in Oregon says they can hook me up for 750 + 110 shipping or for a "solideal" brand they can get me one for 1200 shipped. My good one is a solideal but has an older tread pattern that I don't think they make anymore. Is repair an option?

2) Are there aftermarket pin/bushing sources for these machines? Recommendations?

3)Any experience out there in dealing with having pins and bushings rebuilt?

4) I have noticed that the motor looks just like a Takeuchi (Yanmar?) and the offset boom looks similar on the 135 Takeuchi, what are the chances that the booms come from the same manufacturer?

Thanks for looking and I'm glad this forum is here, I have already learned a lot. My plans for this machine are to get it in good working condition and then make it safer with a ROPS and a seat belt and maybe even replace the lights. If you think I would be better off selling it and saving up for a good unit say so, you won't hurt my feelings! TIA, Kief.

 

[willie59]

Get a price on rubber tracks from McLaren Industries in California, theres a link at the top of this site. I buy most of my tracks from Rubbertrax, but they ship from Conyers GA, a bit farther to you. You shouldn't have a problem with rubber tracks on this small a machine, and you don't want to have to put out the bucks to change all the components to steel tracks, unless your working in material that's destroying your rubber tracks. Plus the rubber tracks give you a lot more comfortable ride. Aftermarket Komatsu pins/bushings? There ain't much anything "Komatsu" aftermarket, especially small, grey market pins/bushings. Contact Bobby Hudson at Hydraulic Circuit Technology, hctkits.com, for info on the auxilliary circuit relief valve.

 

[Elbonk]

I guess I would be looking for metric stock to make or to have a machinist make my own pins.
I have a friend who has access to standard sizes of stock as he works for a large industrial manufacturer. I have seen Kubota pins on Ebay and I guess some NOS parts get out once and a while as well.
As much as I will use this I think rubber will be fine.
I will check the link, THANKS!

 

[John C.]

The Komatsu pins and bushings are matched in material and harness. Don't bother trying to make your own. They won't last a tenth of the time the factory one do. I don't understand what you mean by the Komatsu kit. I've worked on that brand for years and never seen a repair kit. You have to order individuall parts. I'm also confused about the boom part. They make an articulated boom which has the pivot between the boom and stick. They also make a swing boom which has the single piece boom and pivots where the boom connects to the house.

As I recall that machine used a gear pump instead of the newer piston pumps. If so, the pressures are lower and the thumb cylinder should handle it if it was a quality cylinder in the first place. You could try East Hill Hydraulics out of Sumner, Washington. They made a bunch of that stuff for Highline Portofab for years.

Tread pattern on rubber tracks doesn't mean a thing on these machines. Buy what make sense to you. I don't believe you can get steel tracks for this machine.

Good Luck!

 

[Elbonk]

The Komatsu pins and bushings are matched in material and harness. Don't bother trying to make your own. They won't last a tenth of the time the factory one do. I don't understand what you mean by the Komatsu kit."
**I asked the komatsu dealer to price all the pins and bushings for the boom and the big pin at the pivot point.. He just gave me a $4500 price**


I've worked on that brand for years and never seen a repair kit. You have to order individuall parts. I'm also confused about the boom part. They make an articulated boom which has the pivot between the boom and stick. They also make a swing boom which has the single piece boom and pivots where the boom connects to the house.
**this machine has the pivot point where the one piece connects to the base.***
As I recall that machine used a gear pump instead of the newer piston pumps. If so, the pressures are lower and the thumb cylinder should handle it if it was a quality cylinder in the first place. You could try East Hill Hydraulics out of Sumner, Washington. They made a bunch of that stuff for Highline Portofab for years.
***The PO told me that he bent two cylinders and gave up.. thats all I know. The thumb pivot point is welded on and is not incorporated into the pin on the bucket as I understand many are if that is an issue***
Tread pattern on rubber tracks doesn't mean a thing on these machines. Buy what make sense to you. I don't believe you can get steel tracks for this machine.
*** I know tread doesn't matter on a skidsteer but it would be better for resale if I unload it someday. People wear socks and shoes that match, why shouldn't my mini-X:idea -except for the price$$$. ****

Good Luck!

Thanks for the reply.

 

[John C.]

OK, now I've got an idea of what is going on.

In my experience the worst joint is usually the kingpost main pin. That is the vertical pin and set of bushings. There are two bolts on the top plate for that pin. The holes are slotted for those bolts to allow some movement. There is usually some movement even on new machines. If those bolts are broken off you will need a new pin and the bushings that go with it. The other trouble spot is where the boom connects to the kingpost. As I recall there are no bushings in kingpost, just in the boom base. Examine the joint carefully to see where the slop is. If the slop is in the kingpost you will have to weld and bore the bosses back to standard. There are bushings in the base of the boom that can be replaced. The Komatsu dealer probably gave you the price of every pin and bushing from the house to the bucket.

The thumb set up sounds like a shade tree job and there is likely an engineering problem. I've seen those tack on units before and didn't think they are very robust to begin with.

As far as the tread pattern on the tracks go, everyone looking at buying a used machine can expect some kind of problem happening at some time. It is pretty normal to have one side cut up while the other is in good condition. Finding a machine with mismatched tracks is really pretty normal. Finding a used mini with two good tracks now days is a bonus.

Good Luck!

 

[Elbonk]

Thumb is definietly shade tree, somewhere between mechanical and the right way. I don't have broken bolts.. will try to post a picture soon. THANKS!

 

[willie59]

I'm just a bit puzzled when you said the thumb has no relief valves and the PO gave up on the thumb after he replaced two cylinders. If this is true, this is obvious, without relief valves you WILL destroy thumb cylinders. When you curl the bucket into a log/rock against the thumb, the bucket circuit has enough power to bend the thumb cylinder if it doesn't have relief valves. I don't know what kind of auxilliary setup you have, but the thumb itself may not be your problem. Having no reliefs in the circuit is a definite problem.

 

[Elbonk]

Here is a pic of the vertical pin that is loose. The bolts are still in the plate on top, not sure if those are the ones referred to that could be broken..
The other pic is of the thumb mount.

 

[Elbonk]

More

Here is a pic of the cord hanging out of the bad track-note the uneven spacing of the bars by the drive wheel.

Another of the stretched tread on the "Dominator" brand track.

The last pic is of the "Solideal" tread, the angled bar tread is unique and I don't think it is available anymore.

 

[Elbonk]

Thumb: My understanding was that the thumb cylinder, as ATCO said, would be crushed by the larger bucket cylinder w/o a relief valve , or the bucket could be damaged as well if things didn't line up right. I need to do some research and see what size cylinder to use and how to plumb the relief valve in, where to get it, etc.. Will check the link listed..

 

[Elbonk]

Track prices.. I had a quote from McLaren for $1400++.. $1200 if the track rides on the V-groove(?).. I'll have to look at that.

 

[willie59]

Dude, your missing my point! The size of the cylinder does not matter in this case. To use an extreme example; if you had a thumb cylinder that only had a 1/4" rod, you couldn't damage it by "rolling the bucket into it" if it had relief valves that would "pop open" and allow the thumb to "move" when the bucket contacted it. The relief valves are one of the most important components on any hyd circuit, without them, all hyd components will be damaged. You have to have relief valves on any hyd component.

 

[Elbonk]

Exactly

I'm just a bit puzzled when you said the thumb has no relief valves and the PO gave up on the thumb after he replaced two cylinders. If this is true, this is obvious, without relief valves you WILL destroy thumb cylinders. When you curl the bucket into a log/rock against the thumb, the bucket circuit has enough power to bend the thumb cylinder if it doesn't have relief valves. I don't know what kind of auxilliary setup you have, but the thumb itself may not be your problem. Having no reliefs in the circuit is a definite problem.[/QUOTE

I think I get it- say the relief valve was rated for up to 1500 lbs. and if I rolled the bucket with a rock and kept going the valve would allow any pressure in excess of 1500 lbs. go back into the hydraulic resevoir (or wherever it goes) instead of allowing the power of the bucket ram to bend the thumb or its cylinder (the PO said he previously bent the cylinder rods)
By size of cylinder I am referring to actually finding a cylinder that is rated appropriately for the work the thumb will do and the compressed and extended length for the geometry of my thumb set up not how much force it can handle so as to eliminate the need for a relief valve.. sorry if I didn't clarify that before..

 

[John C.]

Basically ATCOEQUIP is correct in that you will have to have some kind of relief valves installed in the thumb circuit. They can be cartridges installed in the main valve or an aftermarket cross over relief installed somewhere on the boom. Check with your Komatsu dealer to see if they have the cartridges available. As I recall they are way more expensive than the aftermarket unit but all you had to do was remove the plugs from the main valve and screw in the cartridges. A hydraulic component supply house could supply you with a cross over relief. You would have to plumb an extra drain line from the valve and plumb the circuit lines into and out of the cross over.

Good Luck!

 

[HillBoy]

Track prices.. I had a quote from McLaren for $1400++.. $1200 if the track rides on the V-groove(?).. I'll have to look at that.

From what I see on their site, McLaren offers not only rubber tracks for Komatsu PC30 Avance R , but also steel track and steel track with rubber pads (Hybrids). It may be worth for you to compare the prices. We run McLaren Hybrid steel tracks with rubber pads on our mini Kubota KX 121-3 and so far we have been very pleased. We put the Hybrid right on the same undercarriage the old rubber tracks were on -- no need to change anything. The steel tracks with rubber pads will definitely lasts you much much longer than the rubber tracks, especially on this small machine. Anyway, this is just from our experience -- it's really up to what kind of jobs you do...

 

[Elbonk]

Right now price is an issue for me. I mainly plan on using this for work around my place which has a lot of rock but it's not so bad that it would be like working in a quarry.. I definitely don't want to get a poor quality rubber track that will fail prematurely.

 

[HillBoy]

Right now price is an issue for me. I mainly plan on using this for work around my place which has a lot of rock but it's not so bad that it would be like working in a quarry.. I definitely don't want to get a poor quality rubber track that will fail prematurely.

Just by looking at your pictures, I can tell you that your rollers are running on the top of the metal teeth (what you call the the V groove)...

 

[willie59]

Just by looking at your pictures, I can tell you that your rollers are running on the top of the metal teeth (what you call the the V groove)...

I didn't look at them that closely, but now that you mention it, something don't look right they way that track is riding on the sprocket. Wrong track for the sprocket??? Someone has installed rubber tracks on a steel track undercarriage??? Hmmm.

 

[Elbonk]

If you are referring to the top pic- the cords are broken in the track and then they get out of sync as the bars stretch apart and eventual the point on the sprocket will ride on the bar and not in the hole... probably why the the top roller failed. That picture makes it look like it is on the bars, the other side works fine.
I found out that Viqan will send me two new tracks for around $1600-shipping included and I'm waiting on a response from Dominion who the United Rental shop manager says he uses and he likes their product.
I changed the oil today, greased it and found out that I had three broken zirk fittings, one bearing wouldn't take grease as the bearing grease hole didn't align. Fixed and greased..
Anyone found that the threads are a bit different on the zirks? 1/8 pipe thread or metric?