SEE - Retracting tyhe Boom

[peakbagger]

SEE - Retracting the Boom

I had my SEE out last weekend for a work day which was digging in the bony rock filled soil of NH with some rotten ledge to scratch at with the ripper bucket. It preformed admirably but I have come to some conclusions on getting the boom locked at the end of the day. For my rig I have come to the conclusion that trying to get the boom locked just will not happen if the SEE is not level or preferably with the front end tilted down. The speed of the boom just isn't enough to create enough inertia without a bit of help. I find it usually isn't as much of an issue when cold but after running it until the hydraulic fans are running and the oil is hot, it seems to be more difficult. I have found that one option which I really don't like to do is extend the upper boom out straight and use the extra inertia to get it to swing back far enough. I usually try to avoid that approach as whipping the boom back towards the place where I am sitting with the boom full out really take bit of getting used to. I can always fall back to rotating the assembly and using the leveling arms to get it to rotate in place.

The backhoe seems to have plenty of travel speed when in operation so I have discounted a partially plugged hydraulic filter. Anyone else have any suggestions?

 

[Speedwoble]

I had my SEE out last weekend for a work day which was digging in the bony rock filled soil of NH with some rotten ledge to scratch at with the ripper bucket. It preformed admirably but I have come to some conclusions on getting the boom locked at the end of the day. For my rig I have come to the conclusion that trying to get the boom locked just will not happen if the SEE is not level or preferably with the front end tilted down. The speed of the boom just isn't enough to create enough inertia without a bit of help. I find it usually isn't as much of an issue when cold but after running it until the hydraulic fans are running and the oil is hot, it seems to be more difficult. I have found that one option which I really don't like to do is extend the upper boom out straight and use the extra inertia to get it to swing back far enough. I usually try to avoid that approach as whipping the boom back towards the place where I am sitting with the boom full out really take bit of getting used to. I can always fall back to rotating the assembly and using the leveling arms to get it to rotate in place.

The backhoe seems to have plenty of travel speed when in operation so I have discounted a partially plugged hydraulic filter. Anyone else have any suggestions?

I know you have been around here a bit, so you are aware the boom is over center, correct? You have to pull it up, then as it hits the peak, reverse the lever and it drops right on. I agree, it is a bit concerning doing it right towards your face, but it works.

 

[The FLU farm]

That is odd, peakbagger, unless as Speedwoble suggests, you're not reversing the lever when the boom is getting close.
I generally get it to lock in just fine even at 800 to 900 rpm, and have never paid much attention to how level or leaning the SEE is.
Why such low rpm? I don't like all that mass coming at me any faster than it has to.

 

[peakbagger]

Yup, I know its over center and I do reverse the lever, unfortunately it just doesn't travel far enough to catch especially when the fluid is hot.

 

[The FLU farm]

I would start looking for something that blocks the boom's travel. Then make sure that the pivot moves freely. Then that the "locking flap" is in the correct position fore and aft.
Since you've probably already looked into those things, about the only other explanation I can think of is that the cylinder isn't operating correctly, or is the wrong length.

Not operating correctly would include that there's air in it, but after all the work you've done, that doesn't seem likely. And it puzzles me that it makes a difference if the fluid is hot. If a hose is pinched or kinked, hot fluid should flow through the restriction easier than when cold.

In my experience there's more than enough oomph in the system to operate correctly at almost any temperature. It'll be interesting to see what the problem turns out to be, so keep us posted.

 

[tennmogger]

I do not have an SEE but recall this discussion before, probably on Benzworld Unimogs. As indicated above, when the boom is lifted to the top, with speed, and still has inertia, shove the hydraulic control in the opposite direction. The engine probably has to be rev'ed up to normal operating speed for good hydraulic flow. This is reportedly what is needed to set the boom on the latch. I have no clue why that works!!! Or I do not remember right!! Either way, no harm done.

 

[The FLU farm]

You remember correctly, tennmogger. It's an over-center design, so it's only a matter of timing the movements of the lever correctly. Or should be - there might be more to it in peakbagger's case.
Both the SEEs I use will easily lock the boom at low rpm, at least if they're not on a steep uphill.
Why it works? As the cylinder runs out of travel, and is still moving the boom in/up/back, by extending it again the boom now wants to continue in the opposite direction (compared to normal) which brings it all the way back to the lock position. Without enough inertia it'll stay in the normal position, never making it "over the top", and with too much it gets kinda scary, I think. I know the backhoe is built to take it, but I just don't like the slamming and banging so I prefer doing it slowly. If it takes two tries, so be it. That won't contribute measurably to any extra wear.
Not the best explanation, but I hope it's somewhat clear. Had I not read about it while waiting for my SEE to arrive, I would've never figured it out.