Hydraulic hoses failing

[Henry jnr]

Running a John Deere 648L grapple skidder with about 6,500 hours total and specifically the hoses running to the grapple cylinder keep rupturing every 200 to about 300 operating hours.
Using OEM replacement hoses from the dealer, proper fittings, routing them the same way they came off. The hoses aren't rubbing on anything that I can see, so no sharp edges or pinch points in the routing. we're mostly pulling 8 to 12 inch diameter stems in mixed hardwood. When the hoses fail, it's always the same spot near the fitting on the cylinder end. They'll develop a small bubble in the outer rubber layer then blow within the next few hours of operation. Dealer mechanic suggested on a call that the cylinder itself might be spiking pressure but testing showed that the pressure is within spec
What could be the issue?

 

[What]

They could be too long, or too short, causing them to kink. Have someone operate the grapple and arch through their entire range of movements, while you stand behind it and watch what is happening to the hoses. I actually found that a few hoses on some of my machines needed to be longer, and others shorter than stock.

 

[Bethel33]

Check if the hose has enough slack to flex with the cylinder movement

 

[cur1ouscat]

yes, it's important to recheck the hose routing, then check the cylinder, and there's nothing wrong with checking the hydraulic filter, cause a clogged hydraulic filter can cause pressure spikes

 

[Alan]

Since it’s always blowing near the fitting, you should look hard at flex and strain at full curl. Even if pressure tests fine, a hose that’s getting side-loaded or twisted at the cylinder will fail exactly like that.