JCB803 hydraulic oil leak mystery

[AndrewMawson]

My 1990 803 decided to dump a load of hydraulic oil a couple of days ago. I'd used it lightly during the day, parked it up in the tractor shed, and in the morning there was a large pool of oil under the frame. Too much to tell exactly where it had dripped from. I cleaned up, moved it to a different bit of floor and left it over night. This time a much smaller pool with the drips coming from the cover that gives access to the rotary coupling.

i moved the Rams to the correct position for a level check and had to add at least a quart. I took the floor up to inspect the rotor. A bit a oil but nothing significant. Blew it clean with an air line, finished with a rag, then took her out to exercise the track motors and dozer, spinning the cab a bit. No signs of a leak.

so yesterday I put her up on a couple of railway sleepers, crawled under, took the cover off, and inspected below. Again a bit of oil but nothing significant Cleaned her up and went for another trot round. Back on the sleepers for a look and nothing. I repeated this twice but nothing showing. Left her for a while, not a single drip, nothing ! Cover back on and zero drips ..

now in my experience these things don't just go away. What the heck was the leak?

[ianoz]

Andrew , It is a JCB , so just marking it's territory .
I have been on a 38 ton Cat excavator last couple of weeks. Had a paint mark on the drive hub .Park with mark to the bottom, to keep the oil in . It is now in workshop getting a new seal .

[Muz]

Might not be the rotary, last time I looked inside an 803 it was a complete dogs dinner of hoses going in every direction, so, a drip from a hose higher up could be likely, just hard to see