Well those loader shear pins do shear...

[otus_branch]

Yes those loader shear pins do shear, and I suppose I should be grateful that my foolishness did not lead to anything worse. The situation was me enjoying my new Markham grapple (i.e.- "Extreme Gator Mini Rake) on our Kub L-39, unloading a trailer full of locust logs (some longer than 20'!) from next door. In order to reach a few of the logs, I had to grab them off-center, which of course led to tilting, which can't be good for anything. In general, I would set the log down once I realized that it was not centered, re-position the tractor, and lift again. But I got in a hurry, and one time it looked like setting the log down would crush a side-light on the trailer (not too well-protected on my trailer), so I decided to go for it and keep moving, tilt and all. Well, I cleared the trailer and its lights, but then POP goes the grapple, right off the skid steer mount, and those shear pins which go into the bottom of the grapple are missing a few millimeters of steel.

My questions are: (1) what can I expect to pay for replacement SS loader mount shear pins for the L-39? and (2) even though the broken pins were clearly due mostly to operator error, I also previously observed that the Markham grapple fit loosely enough to permit a little side-to-side movement under high-torque grappling. It certainly seemed to have more slop than the (Kubota) bucket. Could a slightly loose fit contribute to shear pin breakage?

I sure have been publicly airing a lot of my tractoring mistakes here at TBN! I hope my mistakes can at least help other noob's avoid doing the same...

-otus

 

[TalonDancer]

Yes those loader shear pins do shear... but then POP goes the grapple, right off the skid steer mount, and those shear pins which go into the bottom of the grapple are missing a few millimeters of steel....

I sure have been publicly airing a lot of my tractoring mistakes here at TBN! I hope my mistakes can at least help other noob's avoid doing the same...

-otus

Well you certainly have helped me I didn't realize that the skid steer QA had "shear pins".

Are they the tapered pins that hold the bottom of the implement to the skid steer plate?

Talon Dancer

 

[Leejohn]

I would also like to know where the shear pins are at on a loader? Lee

 

[MrJimi]

I am wondering what are these shear pins you speak of? are they the angled pins that go into the bottom of the attachment like this picture?

Jim

 

[otus_branch]

Well, thanks for the replies so far. Yes, I do mean the tapered steel pins that slide downward into the QA implement (a grapple in this case).

It's funny, because right after I had done the damage to the loader pins, I described the situation to a neighbor of mine who has farmed most of his life and has an orchard that is truly inspiring. I didn't know what to call those loader pins, so I described them at length, and he said "Oh, you mean the shear pins." And I replied, "Well, they're not like shear pins on a PHD or brush hog." And he said, "Well they are a TYPE of shear pin." So I used the term here at TBN with some (apparently unfounded) confidence.

Anyway, I hope I cleared up the semantic confusion. Now, has anyone else snapped these loader pins? Could my grapple be too loose, and could that be part of the problem? I plan to call Markham Welding tomorrow, and ask if they have seen similar fit-problems.

My local Kubota dealer quoted me $35 per pin (parts only). I plan to check the loader again when I get home, since apparently the L-39 takes two different pins depending on the loader serial #. Also, I am not entirely sure whether I need to replace both or just one. Their parts guy had not sold any of these pins to anyone yet, and the dealer did not have any (for either loader type) in stock.

Any advice on things I can do to avoid this mistake in the future (above and beyond not dragging around grossly off-center logs) is greatly appreciated.

-otus

 

[MarkV]

Otus, sorry to hear of the problem I can’t recall hearing of anyone breaking one of the “shear pins” or mounting pins on the quick tach mount before. As far as the grapple mounting plate being looser than the stock bucket that does not surprise me. I am unaware of any standards established in the industry for those mounts. Each of the three attachments that I use on my L39 loader is somewhat differently configured on the mounting plate. Not having ever noticed a side to side movement with the different configurations on my attachments I suspect that the off center loads a grapple can apply is the problem.

There has been talk of having problems with the tapered pins fully engaging in the mounting plate of some attachments. Several have added washers to the tops of the pins forcing them to more fully engage. That may be worth a try in your situation to see if it eliminates the movement you expieriance.

MarkV

 

[slowzuki]

I broke the tips off mine using a loose fitting pair of forks. I adjusted them tighter and shimmed them and no more trouble. If the forks were any looser I would have had to build up the slots instead.

 

[texasjohn]

Thanks for the post and discussion... I will be building an attachment to the QA plate and now will make SURE that the pins engage and tighten down so that there is no play.... previously, I had just assumed that all that was needed was entrapment of the pins but now understand that TIGHT entrapment of the pins is desirable.

 

[TalonDancer]

Thanks for the heads up...
I'm glad to know that the tapered QA pins appear to be the weak link in the QA attachment. Hopefully _when_ I do something stupid, my QA pins will shear off and protect the rest of my QA and the implement.

Even though $35/pin is a bit of cash. I rather replace two pins than have to repair a damaged QA plate, links, etc.

Talon Dancer

 

[otus_branch]

Thanks TalonDancer, slowzuki, and MarkV for the helpful advice. When I replace the pins on my L-39 (it needs both), I will be sure to shim them with some washers to get a better fit. I have not yet looked at the mount to figure out exactly where to put those washers yet -- between the springs and the handle I assume -- (by the time i could get to the tractor last night after work to write down the serial number, it was dark and VERY cold), so if anyone has pictures of a tightened-with-washers QA mounting, I would greatly appreciate seeing them. Recommended sizes of washers for the L-39are also appreciated.

Texasjohn, since you are handy enough to be building your own QA plates, I would recommend duplicating the Kubota OEM bucket's measurements as closely as possible, as it really is impressive how well that fits..

In general, I will interpret any side-to-side movement on any future loader attachments (the is a hydraulic PHD on my wish list, which I imagine can exert plenty of torque on the mount pins as well) as a need to tighten the mount further, in order to avoid this problem in the future.

And yes, the $70, while more than a tad painful, is a fair price for a lesson learned...

-otus