T
Taat
Active member
Updated result of case drain leakage. Cold and hot oil. Same measuring time in same directions. Obvious difference. Hot oil is about 0.7 litres and cold about 0.2. 30 seconds of measuring time.
T
Taat
Active member
Mick-the-fitter
It’s what I do!
So an educated guess would be wear in the rotating parts!
T
Taat
Active member
Certainly. The drift is also more noticeable with hot oil. But the slew brake applies faster compared to the cold oil.
I am certain that the bores on the cylinder block cause this. I also believe that they weren’t machined properly from the start, since this slight drift was apparent even when I put the new parts in, but I didn’t think much of it because because it was still better compared to when I got the machine.
I am tempted to just take the brake valve off tomorrow, replace the cylinder block with the old one, have the valve plate lapped to its surface before assembling and see the results. The old cylinder block dimensions and tolerances are still up to spec and I had the contact surface ground down minimally (0.01mm of material removal).
T
Taat
Active member
I replaced the cylinder block. Here are the results. Case drain measuring time was one minute this time. In the picture the bottles are for left and right. Both warm oil (not hot but definitely on a working temperature). Sometimes there is more leakage to the left, then another more to the right, but I was doing these tests on a slope so I guess it depends which side is more tilted?
Anyway in the video you can see that leakage is now minimal. This is the best result I have ever gotten. Warm oil with hoe attachment fixed to the ground and only about 0.1 litres in a minute. I guess if I would measure with free swinging in the circle it would be non existent. I have yet to test that. I am very satisfied with this result.
As for the drift, on level ground with the machine lifted to the max with the dozer blade there is no drift whatsoever now. Slight drift is only seen and felt on a slope with machine additionally lifted with the dozer blade. So only in extreme condition there is drift now. And this is with working temperature oil. Before there was even more drifting and with cold oil.
Also the valve plate seemed okay. Some wear pattern but couldn’t feel and had it lapped down pretty quickly. So I guess changing the springs and the shaft/spline did something.
As for this slight drift, but this is now only apparent in extreme measures… I guess I just have to accept that the machine has 12.500 and live with that. Maybe this is even normal? I don’t know.
Anyway the drift is almost nonexistent for now and the case drain leakage can probably be compared to a completely new hydraulic motor right now.
With this I hope that my slew adventure has come to an end, at least for a few more hours!
Anyway in the video you can see that leakage is now minimal. This is the best result I have ever gotten. Warm oil with hoe attachment fixed to the ground and only about 0.1 litres in a minute. I guess if I would measure with free swinging in the circle it would be non existent. I have yet to test that. I am very satisfied with this result.
As for the drift, on level ground with the machine lifted to the max with the dozer blade there is no drift whatsoever now. Slight drift is only seen and felt on a slope with machine additionally lifted with the dozer blade. So only in extreme condition there is drift now. And this is with working temperature oil. Before there was even more drifting and with cold oil.
Also the valve plate seemed okay. Some wear pattern but couldn’t feel and had it lapped down pretty quickly. So I guess changing the springs and the shaft/spline did something.
As for this slight drift, but this is now only apparent in extreme measures… I guess I just have to accept that the machine has 12.500 and live with that. Maybe this is even normal? I don’t know.
Anyway the drift is almost nonexistent for now and the case drain leakage can probably be compared to a completely new hydraulic motor right now.
With this I hope that my slew adventure has come to an end, at least for a few more hours!
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Mick-the-fitter
It’s what I do!
Even when brand new motors or pumps they design a leak as it keeps every thing lubricated at a drip speed
T
Taat
Active member
Yes that makes sense. What about this slight drift (although it’s almost completely gone now)? Do new machines experience that? Let me note that drift on my machine can be felt only on big slope with hoe attachment fully extended, if I tuck the bucket closer the slew motor holds fine… Is that normal?Even when brand new motors or pumps they design a leak as it keeps every thing lubricated at a drip speed
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