715 backhoe loader question

 I would look close at the cylinders for internal leakage in one or both. I had a Pettybone loaded that did the same thing and one piston seal was bad allowing the oil past to the dump side.

The bucket section is a 4-way section with the "A" work port connected to the barrel ends of the bucket cylinders (Figure I). The bucket cylinders are connected in parallel. The bucket section spool has 3 positions and is spring centered to neutral. Pushing the spool in, (Figure J) directs oil past the lift check and out the "A" port to extend the cylinder rods and dump the bucket. A floating check between sections prevents oil flow back into the level section work port. An anti-cavitation ball check, located in the lift checkplug assembly, prevents the oil from flowing back into the work port of the self-leveling section. An anti-cavitation ball check located in the lift check plug assembly, prevents bucket cylinder cavitation, when the bucket "dump" over center, by allowing the oil to flow from the sump passage into the "A" port cavity.

Pulling the bucket section spool out, (Figure K) delivers oil past the lift check and out the "B" work port to retract the bucket cylinder rods and "roll-back" the bucket.