2001 Cat 315bl excavator developed a swing issue today. Machine will only swing approximately 200 degrees and then stops as if the brake was applied. Smooth operations in both directions, but will not make a full revolution. Was working without issue a week ago. Checked swing motor oil level, all good. Checked and regreased swing bearing, upper and lower fittings and at 180 degrees as well. Did not take but a few pumps to have grease pushing out. Grease did not look milky or the like. No odd noises, clunking or the like. Engine will lug down when trying to move beyond the 200 +/- degrees. Stops in the same spots in both directions. Any thoughts as to where to begin diagnosing my issue would be appreciated. Nick
Check the swing parking brake solenoid for power. Check pressure on the swing brake hydraulic line. Pull the swing motor and operate the swing while watching the output gear turn. If it will turn multiple revolutions, then your problem is likely in the reducer below.
Thank You John C. Assuming the power to the solenoid would be present only after the control lever for the swing motion is moved? Might anyone have operational description of the process and series of events when swing operation is active?
The swing parking brake is spring applied and hydraulic released. The solenoid will have power to it at all times. Control is done by grounding the circuit through the controller. The swing parking brake is released whenever a function is used and will be set when nothing has been operated for approximately seven seconds.
Something jammed in ring gear?
Play in swing bearing?
Thank you for the additional considerations. No sign of swing bearing wear or excess play. Will need to lift swing motor off to check inside for obstructions of ring gear assembly/reducer. Will update with findings and /or solution to the problem once I am able to get back to it. Up till yesterday there was no issues with the operation of the machine, will swing smoothly still in both directions for about 200 degrees of rotation. No engine load until it gets to both ends of that rotation. It felt as if the brake was being applied at that point, will rotate back smoothly with no engine load noted, no noises, clunking or the like. Gear oil level was fine, lube was clean and had no ill smell to it. Swing bearing grease looked fine when re-greasing it at 0 degrees and at 180 as well. Approximately 2 years ago, lost the seal to the swing motor, popped the dipstick out of the motor and tossed it up onto the main boom. With advice and insight from those on this site, was informed that it was not uncommon for that to happen. Pulled the swing motor, replaced the bearings and shaft seal, O rings, replace the gear lube after inspecting the ring gear assembly. All components looked in great condition, reassembled and has been problem free. Until yesterday that is.. Will start with verifying the power to solenoid, however am assuming it must be there to start with as there is no problem initially and/or on either end of the limited swing range that is now present. But, do not understand as of now how I could loose the ground to that control circuit at those specific end of ranges consistently. More learning to do on this end. Appreciate the replies. Nick
Issue resolved. In the end it was a water / ice issue. Water had leaked down into the ring gear cavity, and with the temps nose diving up here in the Northeast over the last couple of weeks, it froze. Ultimately impacting the swing motors ability to move through it. I got back to diagnosing today and that was the end result and issue found. Temps here (NH) over the past few days have stayed above freezing and allowed some melting in there - which allowed the machine to swing all the way around today. I started down the checklist.. 1. Power was present to the brake solenoid. 2. Had hydraulic pressure at the brake port. 3. Lifted the swing motor and tested it for rotation - unimpeded. 4. Reducing gear set all looked fine, lube was clean and without contamination. 5. Cleaned the access cover to the ring gear - removed inspection/greasing port cover and found the issue. I could see free standing water in there. Operated the machine and could view the ring gear through that port as I was swinging around. That is when I spotted the matching teeth in the ice block. The machine was able to swing all the way around due to some of the melting. In hind sight, should have started there. Drained about 4 gallons of water out thus far. Heat gun in there to see about melting and draining the remaining water. The ice block can be seen in the attached picture. Will re-grease prior to resealing the inspection port. Thanks Again
The water is probably getting in through the rubber boot around the swivel. I suggest you inspect/replace it.
Thank you for that insight. The swivel joint is on my hit list to pull, inspect and install new O rings as the machine has not been moving correctly. Perfect time to replace the sealing boot when I get back to it.