Komatsu D31a-16

[BMsuper]

OK, shot a video. It shows the angle cylinders do not retract all the way. They seem to extend all the way, left and right. You can see how the angle cylinders keep the blade pitched forward not allowing the angled tilt rod to tilt the blade to the left. I don't know how to adjust the angle cylinders to retract all the way? Any Ideas? this is a 3 minute video, I don't know if this website will accept a file this big. No, I can't post that video,just be too long? Give me an email address and I'll send it. Bob

 

[BMsuper]

Won't let me post a video?

 

[Simon C]

I would leak test those cylinders, as all other testing becomes irrelevent if one of them is by-passing inside. Might have to install an extention hose to be able to run by pass oil into a pail.
Had one just recently that the rebuilt cylinder was completely gone and the one that was weeping was okay.
3 cylinders to tests and after that you can start bleeding, otherwise the first time it hits something firm the cylinder will retract.
If that does not reveal a leak then you need to pressure test each line for how much pressure there is.
Simon C

 

[epirbalex]

OK, shot a video. It shows the angle cylinders do not retract all the way. They seem to extend all the way, left and right. You can see how the angle cylinders keep the blade pitched forward not allowing the angled tilt rod to tilt the blade to the left. I don't know how to adjust the angle cylinders to retract all the way? Any Ideas? this is a 3 minute video, I don't know if this website will accept a file this big. No, I can't post that video,just be too long? Give me an email address and I'll send it. Bob

OK, shot a video. It shows the angle cylinders do not retract all the way. They seem to extend all the way, left and right. You can see how the angle cylinders keep the blade pitched forward not allowing the angled tilt rod to tilt the blade to the left. I don't know how to adjust the angle cylinders to retract all the way? Any Ideas? this is a 3 minute video, I don't know if this website will accept a file this big. No, I can't post that video,just be too long? Give me an email address and I'll send it. Bob

In your post number 24 you said the rams won't extend fully but now do , has something changed . Ram going fully extended while the other not fully retracted probably has something to do with keeping to volume of oil moved the same . The angle rams won't affect the pitch , any force from the blade against them from pitch would bend them , they should have a swivel ball in the ends of them to stop that . The little solid rod is for pitch .

 

[BMsuper]

Simon, The angle rams do seem to extend out all the way but do not retract all the way on either side. I wish I could post this video. The tilt cylinder works fine, travels both ways to the limit. I have no way to pressure test the cylinders. I think I can rebuild these angle cylinders fairly inexpensively right on the machine. Maybe that's next. The picture I enclosed is not of my machine but is a machine exactly like mine. You can see the blade tilts back and the angle cylinders are not extended very far with the blade straight. My blade is straight up with the top of the blade even with the cutting edge. Something is not right.

 

[davejo]

You probably have oil leaking from the rod side of the piston to the barrel side on one or both of the angle cylinders. This is throwing off what the control valve is allowing the other cylinders to do.

This would explain multiple people having the same problem with the lack of tilt and bent con rods. The system is designed to coordinate the length of the 3 actuators with respect to each other mechanically. The adjustment valve procedure shown above sets the baseline relationships.

If one of the cylinders isnt sealing, the actuator relationships are thrown out of balance. If the seal only leaks in one direction, bent conrods and confused diagnoses might ensue.

I'm not a trained mechanic but I have looked at your pictures and thought much about how this Rube Goldberg contraption might function. And fail.

 

[Tinkerer]

Won't let me post a video?

You need to add your video to a website like YouTube.
There are quite few video sharing sites that you can use similar to YouTube.
After doing that post a link to it in your thread that you have here.

 

[BMsuper]

You need to add your video to a website like YouTube.
There are quite few video sharing sites that you can use similar to YouTube.
After doing that post a link to it in your thread that you have here.

I will do that. Thank you

 

[BMsuper]

OK, I added a video to you tube. I'll see if I can list it here. It shows the angle cylinders not retracting all the way. The blade is pitched forward not allowing the tilt rod to push the blade to the left. If the blade was held back by the angle cylinders it would push to the left. angle/tilt problem

 

[BMsuper]

You need to add your video to a website like YouTube.
There are quite few video sharing sites that you can use similar to YouTube.
After doing that post a link to it in your thread that you have here.

Tinkerer, thanks for telling me how to add a video. I'm old and not in good health so I appreciate the advice. Just trying to get this machine working correctly so I can help my son out on his property. Bob

 

[HarleyHappy]

Good video. I will have to watch it more later but there is something wrong but not sure where.
What is the major complaint?
I see a problem with the tilt cylinder not tilting past center and that linkage is a bit screwed up and unfortunately being off kilter up top pays huge dividends on the tilt cylinder stroke.
Not sure what’s original or not on the cylinders.

 

[BMsuper]

Thanks for getting back to me. I believe all the components on this machine are original. Only 2900 hours on the clock. The major complaint is that the blade will not tilt left. The tilt cylinder travels full stroke in and out but because the tilt rod is pointing almost straight forward it will not tilt the blade to the left. The angle cylinders are pushing the blade forward, they are too far out, not holding the blade back to allow the tilt rod to push to the left. When you angle left and right the angle cylinders do not retract all the way. They seem to extend all the way out but will not retract all the way in? I read in the shop manual it says to adjust the cylinders to 720 to 760mm (pin to pin sum of both sides) but it doesn't tell you how to do the adjustment.

The previous owner had a root rake installed on this machine and may have abused the blade trying to root out stumps. This may have damaged the angle cylinders pulling them forward and causing internal seal damage. If I knew how to adjust the angle cylinders I would try that and if that doesn't work I'll install new seals in the angle cylinders. Not sure what to do?

See the enclosed picture of another D31-A just like mine. The blade pitches back and the angle cylinders are not out very far at all. The tilt rod is diagonal but more left and right rather than forward like mine is. This is not my machine.

 

[Simon C]

OK, I added a video to you tube. I'll see if I can list it here. It shows the angle cylinders not retracting all the way. The blade is pitched forward not allowing the tilt rod to push the blade to the left. If the blade was held back by the angle cylinders it would push to the left. angle/tilt problem

The swivel below the tilting cylinder could be grabbing some, causing part of the problem. Now that I have seen your video, those two angle cylinders would be easy to by-pass test.
Stroke one cylinder to the end, disconnect the rod end hose and put into a pail and restart and Rev the engine up and try to stroke it out further on the same cylinder. If oil pours out the disconnected fitting, the cylinder is junk.
Then hook back up and test the other cylinder with the rod pushed out and fitting disconnected the same way.
Just to let you know, I tested a guys tractor that would not steer, he had changed the orbitol valve and wanted me to change the pump. I would not without testing the pump pressure which was full.
He insisted I change the pump, I disconnected the tie rod ends only to find out the shaft the tie rods were connected to was seized solid. Unseized and greased and all fixed.
Moral of this true story, test those two cylinders first for free, then test the 3rd tilting cylinder for by- pass and make sure the swivel pin on bottom is not seized. Would be good to get a Komatsu T- fitting to check how much pressure the machine is putting out before buying any parts.
If all that passes you will have to do the bleeding procedure that was listed up above.
Simon C

 

[davejo]

The manual shown in this thread does tell you how to adjust the cylinder length. I agree it isn't easily deciphered, especially to those of us not onsite. Are those the instructions you are following or do you have your own, different manual and instructions?

 

[epirbalex]

OK, I added a video to you tube. I'll see if I can list it here. It shows the angle cylinders not retracting all the way. The blade is pitched forward not allowing the tilt rod to push the blade to the left. If the blade was held back by the angle cylinders it would push to the left. angle/tilt problem

I don't think the angle rams have anything to do with the problem and it looks like they are fine . They just float and are there for the ride . There appears not to be enough movement in the tilt ram . The motor loads up when all the rams are extended which is good .

 

[BMsuper]

OK, next fairly warm day I'm going to do the By Pass test Simon C recommended (above) and will try the bleed procedure again. This tilt problem is the only thing left to fix before I can use this machine. Been working on it for a month. I will post the results here. Thanks for all the info guys.

 

[BMsuper]

I would leak test those cylinders, as all other testing becomes irrelevent if one of them is by-passing inside. Might have to install an extention hose to be able to run by pass oil into a pail.
Had one just recently that the rebuilt cylinder was completely gone and the one that was weeping was okay.
3 cylinders to tests and after that you can start bleeding, otherwise the first time it hits something firm the cylinder will retract.
If that does not reveal a leak then you need to pressure test each line for how much pressure there is.
Simon C

Simon, were you able to adjust your angle cylinder length using the bleeding procedure posted? I read that Plug 1 is actually a large bolt head (maybe 1 1/4") I didn't realize that was a bleeder. I was opening the small 1/4" square headed plugs. I'm going to try that procedure again today.

 

[Simon C]

I just read the bleed procedure. The cylinder leak test is the same on basically all cylinders. I'm guessing the tilt cylinder will fail the test. Just my guess. Let the tests determine the next direction.
Simon C

 

[BMsuper]

Simon, I tested the cylinders as you said and no oil is leaking by. I then followed the procedure to reduce the length of the angle cylinders by opening the large bolt (I didn't know that was a bleeder) and the two square head bleeder bolts on both angle cylinders. I tilted right and angled left and right and the angle cylinders sucked all the way in when angling both left and right. Video Enclosed. Now, I can probably get them to retract even further but right now I have left and right tilt and left and right angle working fine. I might be able to get a little more left tilt but it's fine for now.

Now I have to put it to work to see if it's going to hold. But at least I know what to do if it needs adjustment in the field.

Thanks Again, Bob

 

[BMsuper]

I can probably get more left tilt but at least I can get to work with this thing now. After the angle cylinder adjustments. That's my wife on the machine. Thanks Simon