619B BH up slow and drop like a rock

nav0239

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B6000, B219 loader, 619B backhoe
Jan 4, 2015
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6
Camano Island, WA
I have put the 619B backhoe on my B6000 over the weekend. The dipper arm goes up very slow and goes down very fast, like throwing a rock and there is nothing holding it . So it hammer the ground hard if I did not stop it within one second.

I did make all the cylinder go through a few full cycles. All other parts appear to move normally. Oil level looks fine. I looked around and did not see any leaks except from the oil vent hole.

Any idea where is the problem? I did not touch any of the hoses and connections. It used to work OK when I took it off a few month back. Hope I don't need to rebuild the valves (while I sort of suspected the valve and want to narrow down my hunt next time when I get there).

Also, I noticed the dipper arm droops slowly that may point to an internal leak?
 
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fast*st

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Jun 26, 2012
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18
Northern Mass
Does the main boom drop the same way, wondering if the valve for the dipper is out of adjustment as to its center. Does that backhoe have the pattern switch lever, maybe it got bumped in storage. It almost sounds like you've foamed the hydraulic oil, maybe it has been water contaminated. Check the level, maybe put the bucket down on the ground, tractor off, wiggle all the controls to take the pressure off, each function for 10 or 15 seconds then pull a line off to get a fluid sample, see if its foamy or white.
 

North Idaho Wolfman

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I'm no backhoe expert, but sounds to me if the problem is just with one cylinder that the seal in that cylinder or the valve section for that cylinder is bad and needs rebuilt. ;)

Swap lines to a different section of the valve body and see if the problem moves with the line swap (bad cylinder) or of it stays with the valve (bad valve section).
 

kubotasam

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How many times did you cycle the cylinder? Sounds to me like the oil could have drained back and the cylinder is full of air. That would account for the slow going up. (Air needs to compress before the cylinder moves) Also the air pressure would release faster than hydraulic fluid and the boom would drop much faster. If you cycled the cylinder a bunch of times then my theory is off. But if you only did it once or twice try cycling it a few more times to see if you can work the air out.
 

nav0239

Member

Equipment
B6000, B219 loader, 619B backhoe
Jan 4, 2015
60
0
6
Camano Island, WA
Thank you all for the help. Based on your suggestions, here is my plan of attack when I get there in ~10 days. I will report back my finding / fix if there is interest.

1) cycle the cylinders a few more times. It might be that I did not really fully cycled the dipper arm cylinder because the boom/bucket were in the way?

2) Check if the valve / control and see if there is any displacement.

3) Switch the two hoses to a different valve and see if it behaves differently.

I hope the problem is found/fixed in the first two steps :).

Your ideas really help a lot as it's first time I ever need to deal with hydraulics.

fast*st: the boom behaved normally, slight slower than it should? Maybe it needs more cycling as well? I did check the oil and it looks clear and not foamy. Also, it's stored inside and was working when it was taken off. I will try other things first and then check/change the oil if everything else fail.

kubotasam: I think I cycled the cylinders 2-3 times. I was out of time after put it back on the tractor. Now I think about it, this might be the problem. I hope it is :).
 
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