This 2013 CAT 321D with 7,800 hours has a messy undercarriage. There is a gooey mess leaking out of the swing bearing all over the lower frame. I was called out to it while it had been running so it was good and warmed up. The swing drive oil level was very high up on the dipstick. Cleaned out the front of the upper frame and pulled the inspection cover. Found hydraulic oil at the bottom of the swing gear cavity. I suspect the oil is coming from the swing motor through the gear box and into the cavity. This machine also has a pretty bad engine oil leak. I’ll be taking it apart this week to investigate. View attachment IMG_4891.jpeg
Yup, swing motor shaft seal went out, filling the gearbox, which in turn went out the gearbox pinion seal. Failure to keep the 093-7521 case drain filter changed on good intervals leads to that, or worse. Step one is to cut open that filter.
Our 312 with simular hours was doing that and I resealed the motor (it didnt blow out the gear case seal just over fillimg the gear case) any how with any luck it will fix that one
That’s a good call heymccall!
I just had my swing drive rebuilt for the exact same symptoms. I have changed the hydro filters regularly, but not since the gear started leaking. How does the case drain filter relate to the swing drive gear? What would this filter being plugged indicate? The hydraulic shop that rebuilt mine replaced the main bearings in the drive. Just wondering if there is a root cause I should be looking for?
The filter being restricted increases pressure in the case drain circuit. On this machine the case drain from both travel motors, swing motor, and main pumps are all tied together, before it goes to the filter. Increasing oil pressure in the case of the motor will cause the oil to blow out the output shaft seal. Once the oil gets past the output shaft seal it goes into the gear box and fills it up. Then oil pushes past the pinion gear seal and into the swing gear cavity. Oil will also get pushed out of the gear box breather, unless that’s very plugged also. If you have a restricted case drain filter that can be very bad. Usually debris from a failing component.
Case drain filter looks ok. The engine oil leak is coming from the oil pan so the engine is coming out. That will give me better access to the swing drive too.
Uggh. I have a 2011 321DL with 8k hours on the clock with what we think is an oil pan leak as well.
My 321clcr developed an oil pan leak around 7k hours. I was able to tighten half a dozen or so pan bolts in chassis and it slowed the leak. The other bolts were inaccessible. Around 12k, I finally pulled the motor and redid it, along with the pump coupler, rear main seal and pump input shaft.
Plan on doing the same when we go in - Anything else to consider since it'll be apart? Cheapest time to do anything in there is then.
My impetus for pulling the engine was an injection pump issue. Something in the internal governor. With that said, your engine doesn't have the mechanical pump and cable(s) actuators. I chose to install a reman alternator and starter. Two months later, we closed shop, so someone got a 12k hour 321clcr with a new injection pump, governor actuator and cables, pump coupling, rear seal, pump seal, reman alternator and starter, a new main pump suction hose, new belts and a new idler pulley for the AC compressor.
Engine is out. I like the 2 piece counterweight design. They really formed the counterweight around every component to get as much weight in there they can. The upper counterweight weighs 3,000 lbs and the lower is just about 10,000 lbs. With the engine out of the way it’s open access to the swing drive. I’ll be getting the starter and alternator rebuilt, and replacing the serpentine Belt. View attachment IMG_4921.jpeg
A lot of cleaning to do in there. View attachment IMG_4918.jpeg
Swing drive is out, pinion gear is washed clean from all the oil. Soupy mess in the ring gear cavity. No sign of a blown out motor seal but it’s probably hard as a rock. Reman motor is going back on. View attachment IMG_4922.jpeg View attachment IMG_4926.jpeg
Replaced the bearings and seals in the gear box. Reman motor installed. Frame is cleaned up and going back together. View attachment IMG_4952.jpeg View attachment IMG_4956.jpeg
Looking GOOD!
Engine is back in with a resealed oil pan and a couple other small leaks taken care of. Counterweights are back on. I also replaced the bearings in the idler and ac tensioner pulleys. And changed all of the filters, basically a 2,000 hour service. Put some fresh grease in the swing gear compartment, greased the swing bearing all the way around. Warmed it up and adjusted the swing motor reliefs. They were cranked way in, don’t know how far but I stopped when the gauge went to 4,500. Adjusted them down to spec, 3,800 psi. I think this was the first time I actually had to make relief adjustments on a reman component. I always check but they’re usually spot on. So far so good. Give it a bath and pat her on the butt! This job is done.
View attachment IMG_5041.jpeg
Great job! If you weren't 2K miles away I'd send you my 321DL next week.
Looking good. What did the pump drive coupling urethane look like?
Thank you. Didn’t go there. What did yours look like?
Quite deformed and torn, yet still functional, was what mine looked like.
200 hours since the repair. Everything is looking good. Nice and dry under the engine. View attachment IMG_5506.jpeg
Good follow up...thanks.
Good thread this. Nice job.