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Sloooooooow Dozer Blade

MrEvilPirate

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Sep 21, 2021
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37
Location
CT
Komatsu mini ex. Dozer blade goes down no problem, can easily lift machine. When I raise the blade the machine comes down quickly, but blade struggles to lift up off the ground. Takes like 30 sec to get it back all the way up.

New to me machine, blade was working fine in the shop, got it out into woods today, after about an hour started having the problem. Everything else works fine no problem. 3800 hours. Any ideas?
 

MrEvilPirate

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Sep 21, 2021
Messages
37
Location
CT
Thanks for response. No valves. After the machine sits overnight it is fine again, use it hard for a while and the blade struggles to lift again, no problem pushing down, all other functions are good. Minor fade... but barely able to lift the blade with full throttle seems a lot more than fade to me... it is my first machine.
 

old-iron-habit

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Nov 22, 2012
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Moose Lake, MN
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Retired Cons't. Supt./Hospitals
Few ideas with no guarantees. Could be a hose that is failing on the inside and plugging the hose via a loose flap when the oil flows one way. Or the control valve may be bypassing on the lift side. If it settles back down after raising it. most likely you have a cylinder piston seal that is leaking on the upstroke. nearly all have a double seal, one for each direction so they will still hold in one direction. To test your cylinders hold the control in raise position and see if the cylinder gets hot where the piston is positioned internally. It doesn't take long to warm up if the oil is bypassing. It may not leak until the oil gets hot so you get a bit of better performance when the oil is cold. You never mentioned if the blade stays up after you get it there. If it does it is not the center cylinder piston and is most likely a bad spool in the control that leaks bypasses when the oil is warm and seals in the hold position.
 

MrEvilPirate

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Sep 21, 2021
Messages
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CT
This is a late response and revival of the thread here.
The blade WILL stay up once it is there. So based on your advise I should check the spool.

I assume I identify the blade circuit, then take the spool apart? Are these things you can replace yourself? I wrench on bikes and cars quite a bit, have never worked on hydraulics before. Thanks.

PS I woke the machine up after its winter nap, I added about 3 gal of hydraulic fluid. I can run a lot longer now before the blade gets slow... I guess the fluid takes longer to heat up to the point where it leaks now that there is more of it. No signs of external leakage. It was just low when I got it. After about an hour of pushing over trees on our property and clearing brush the blade gets real slow.
 

uffex

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Good day
Many of the small machines have the blade operated by a cable or pedal (shifting the spool) bothcan be subject to obstructions and adjustments, may well be worth a check.Komatsu small machines power the slew / swing from the same valve chest, if the slew is working good it narrows the possibilities down.
Kind regards
Uffex
 

MrEvilPirate

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Sep 21, 2021
Messages
37
Location
CT
Hello Uffex and thank you for the response.

Slew works fine. At least I think it is as I have no other experience. No issue picking up large boulders and rotating the house, the slew also seems to work very quickly.

I thought about a cable adjustment, but the blade works fine when the machine is cold/just warmed up. It only gets slow when the machine is doing heavy work. Once it cools off overnight it works fine again. So I don't think it is a cable adjustment, unless there is something else I'm not considering.
 

uffex

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Follow your operation cable to the spool. Check the travel distance in and out, then measure again when it acts up again. This should eliminate any cable distortion.
Excellent advice your post can still add up to limited spool movement.
Uffex
 

MrEvilPirate

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Sep 21, 2021
Messages
37
Location
CT
Went back out to the woods this weekend, but couldn't find where the cable for the dozer blade control connects to a spool. I have a manual at home so I'll dig into it more. The symptoms are slightly different now. The blade gets real slow in both directions. I can't lift the machine with the blade anymore when it has been running for a while. If I lift the machine with the bucket, I can then lower the blade. I set the machine down on the blade and it holds no problem. I'll try to figure out where the dozer blade spool is and drag my lady out there next time to try to get some measurements.
 

uffex

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Good day
Illustration of a typical Komatsu blade control may be helpful.
Kind regards
Uffex
upload_2022-5-2_15-35-16.pngupload_2022-5-2_15-35-16.png
 

MrEvilPirate

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Sep 21, 2021
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CT
Following up on my old posts. I was able to locate the spool for the blade. I performed, rather checked, the adjustment at the spool end then at the lever end per the manual. Spool side was perfect. Very minor adjustment on the handle side. The stops on the handle are bottomed out in both directions so I am getting full throw. Cannot see any noticeable change as the blade starts to get slow.
Blade gets slow in both directions. Struggles to lift the machine. Slow to raise the blade back up. Like really slow. But once the machine held up by the blade it does not move, so it can hold fine. Blade does not drop down if I leave it up. Works great when machine is cold. Using the blade a lot makes it slow moreso than just pushing over trees and moving brush around.

Any suggestions on next thing to check? So far cable adjustment is off the list... thanks!
 

Angel_Rod

New Member
Joined
Dec 29, 2022
Messages
2
Location
Florida
Did you ever find this out? I have a 2014 Volvo EC35C and am having the same issue where the blade goes down just fine but coming up is a whole other story.
 

MrEvilPirate

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Sep 21, 2021
Messages
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Location
CT
Angel_Rod - no. Although in the winter it was happening way less frequently. So I think temperature related. Mine would only start to get slow after a lot of use, when cold it worked fine.
 

MrEvilPirate

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Sep 21, 2021
Messages
37
Location
CT
PC50UU-2. It is a grey market machine. Interestingly, the youtube videos of this thing I find on the internet all have the engine lid propped open while it is running. I have fresh coolant and a clean radiator. In the summer when digging stumps on real hot days the temp guage would climb into the danger zone... unless I popped the hood. So I started always popping it open when it was warmer than 80 out.
 

Angel_Rod

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Dec 29, 2022
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2
Location
Florida
MeEvilPirate - 10-4! Thanks for the reply. I’ll have to keep looking. Mine slows way down after like 2 minutes of operating it. I haven’t had any issues with lifting the machine yet but, I hope I can find a fix for it soon.
 

uffex

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Good day
Attached may help out.
Kind regards
Uffex
 

Attachments

  • EC35 Blade.pdf
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