Bobcat grapple hose keeps getting knocked off coupler

[Trizguy]

We have a T250 with a Bobcat Industrial Grapple. The hydraulic hoses on the grapple have 90 degree fittings between hoses and the couplers that connect to the T250. We have broken the hose off the top coupler assembly a half dozen times. It appears that when the grapple is tipped all the way back and the jaws rapidly opened, the left jaw will snap back and hit the 90 degree fitting where the hose attaches. The hose attaches the fitting via a threaded tube. Sometimes it just makes a small crack in the fitting at the tube to body connection. Other times the tube comes completely off the fitting. The first few times it happened we thought is was the hose getting caught on something and pulled. We have tried longer hoses and ty-rapped the two hoses together with a sheath surrounding them. The hoses are routed through the rectangular hoop on the T250 arm. We don't think it is from the hose getting caught on something or pulled at the extremes of its motion. We tried a custom fitting that had a stronger tube on the 90 degree fitting. That didn't break clean away but still developed a crack. The coupler is 3 1/2 inches long; total length with the 90 degree fitting is 5 3/8 inches; distance from the coupler end to the centerline of the hose attachment tube 4 5/8 inches. Except for our one try at a custom made fitting, all parts are genuine Bobcat. One would think they should work together. Any suggestions? Move the hydraulic connection bracket on the T250? Is there a shorter coupler and/or 90 degree fitting? Is there a way to limit the distance the grapple jaw can open? ? ? Thanks.

 

[SkidRoe]

Hi Trizguy,
Can you post a picture of the two interfering parts, preferably when they are at the position that causes the interference?
What does the dealer say about this? Sounds like an engineering screw-up to me. I can say that with meaning - I am an engineer.
Cheers,
SR

 

[Fishfiles]

Hi Trizguy,
Can you post a picture of the two interfering parts, preferably when they are at the position that causes the interference?
What does the dealer say about this? Sounds like an engineering screw-up to me. I can say that with meaning - I am an engineer.
Cheers,
SR

it sounds like you got the wrong size or type of grapple , wrong size hose and or the wrong fitttings for your machine --a picture is worth a thousand words

 

[Trizguy]

it sounds like you got the wrong size or type of grapple , wrong size hose and or the wrong fitttings for your machine --a picture is worth a thousand words

Fishfiles and Skidroe.
Thanks for your replies. Pardon my slow response as I was up at the cabin for "vacation" for the past week where there is no internet access.

While up there, I realized that I misunderstood the problem. My hunting buddy handed me a coupler with the right angle connection broken off and I assumed it was the same one we repaired a half dozen times. It turns out that it was the upper connection that broke. He must of snagged something. I replaced the connector with a new Bobcat connector and was back in business. Problem solved for now.

The lower connection is still intact. We had a hydraulic shop make us a heavy duty right angle connector and we ty-rap the hoses together so they stay pointing to the outside. The connector shows it has taken some serious hits but the right angle tube going to the hose is still intact. The grapple jaw has some lost the paint in the area where it hits and is forming some surface rust.
The grapple is the genuine Bobcat Industrial grapple, unmodified by us prior to our custom connector. The T250 we bought used so now I think about it, I can't say for sure that the hose attachment bracket is in the proper place. I may want to make a template off a known standard T250 and check that. The only other thing I can think of is that the bearings on the T250 have worn enough to create movement that is not possible with a new machine.
I did find some other fittings at Fleet Farm and Northern Tool that could shorten the coupling by about 1/2 to 3/4 inch. If the bottom coupler fails again, I will try the shortened version to see if that will stop the interference.
If you are interested in seeing the interference, I will be back up to the cabin in about 2 weeks and can take a picture then.

 

[SkidRoe]

Fishfiles and Skidroe.
Thanks for your replies. Pardon my slow response as I was up at the cabin for "vacation" for the past week where there is no internet access.

While up there, I realized that I misunderstood the problem. My hunting buddy handed me a coupler with the right angle connection broken off and I assumed it was the same one we repaired a half dozen times. It turns out that it was the upper connection that broke. He must of snagged something. I replaced the connector with a new Bobcat connector and was back in business. Problem solved for now.

The lower connection is still intact. We had a hydraulic shop make us a heavy duty right angle connector and we ty-rap the hoses together so they stay pointing to the outside. The connector shows it has taken some serious hits but the right angle tube going to the hose is still intact. The grapple jaw has some lost the paint in the area where it hits and is forming some surface rust.
The grapple is the genuine Bobcat Industrial grapple, unmodified by us prior to our custom connector. The T250 we bought used so now I think about it, I can't say for sure that the hose attachment bracket is in the proper place. I may want to make a template off a known standard T250 and check that. The only other thing I can think of is that the bearings on the T250 have worn enough to create movement that is not possible with a new machine.
I did find some other fittings at Fleet Farm and Northern Tool that could shorten the coupling by about 1/2 to 3/4 inch. If the bottom coupler fails again, I will try the shortened version to see if that will stop the interference.
If you are interested in seeing the interference, I will be back up to the cabin in about 2 weeks and can take a picture then.

Some pictures would be good.
Had a thought of something that might help:
Assuming that the grapple is fouling when in the fully open position, putting stop collars on the grapple cylinder rods to slightly limit the stroke would open up some extra clearance. Yes, the grapple will not open quite as far, but it might be a fair trade-off.
Cheers,
SR

 

[Trizguy]

Some pictures would be good.
Had a thought of something that might help:
Assuming that the grapple is fouling when in the fully open position, putting stop collars on the grapple cylinder rods to slightly limit the stroke would open up some extra clearance. Yes, the grapple will not open quite as far, but it might be a fair trade-off.
Cheers,
SR

Here are some pictures of the interference.



You can see that the grapple jaw can travel past the lower hydraulic coupler



and depending on how the coupler is positioned, they can interfere.



You can see the dents on the coupler and scrapes on the grapple jaw. If the hose is allowed to rotate in toward the center, the jaw will hit the tube on the adapter and break it off. This is our modified right angle adapter. On the stock adapter the tube attaches to the adapter body by brazing (or something similar). We took one of the broken adapters to a hydraulic shop where they drilled and tapped it for a threaded fitting. You can see on the leading hex point that it has taken some hits and is still working. We have reduced the chances of the tube being hit by ty-wrapping the hoses together in a way that forces them stay to the outside. Just as an aside, the hose connection is not mashed because we recently replaced the hoses.

SkidRoe, as the interference is relatively close to the pivot point, limiting the cylinder enough to stop the interference would significantly reduce the opening. I don't think that would work well for the things we do with it.

If it breaks again, I will use a shorter coupler that I found at Fleet Farm. It should move the the right angle adapter back just far enough to prevent the tube from being struck.

Thanks for your comments.

 

[SkidRoe]

Here are some pictures of the interference.



You can see that the grapple jaw can travel past the lower hydraulic coupler



and depending on how the coupler is positioned, they can interfere.



You can see the dents on the coupler and scrapes on the grapple jaw. If the hose is allowed to rotate in toward the center, the jaw will hit the tube on the adapter and break it off. This is our modified right angle adapter. On the stock adapter the tube attaches to the adapter body by brazing (or something similar). We took one of the broken adapters to a hydraulic shop where they drilled and tapped it for a threaded fitting. You can see on the leading hex point that it has taken some hits and is still working. We have reduced the chances of the tube being hit by ty-wrapping the hoses together in a way that forces them stay to the outside. Just as an aside, the hose connection is not mashed because we recently replaced the hoses.

SkidRoe, as the interference is relatively close to the pivot point, limiting the cylinder enough to stop the interference would significantly reduce the opening. I don't think that would work well for the things we do with it.

If it breaks again, I will use a shorter coupler that I found at Fleet Farm. It should move the the right angle adapter back just far enough to prevent the tube from being struck.

Thanks for your comments.

A wise man once said " a picture is worth a 1000 words". I think the biggest problem is those -12 flat face couplings - man, is that male side ever long!! I know this probably is not the slam-dunk answer you are looking for, but try switch to agricultural couplings, at least for you grapple attachment. They are much more compact. Since you grapple is fitted with -6 (3/8") hoses, the flow reduction will be nearly transparent. BTW - where are you located? If you are in Ontario, I may be able to hook you up with parts that wll fix your issue. Hope this helps, SR