Horrible newbie question here: on the right hand side of the driver's seat there is a locked metal flap, under which there metal cap over a tankful of something (hydraulic oil?). When I opened this cap, there was a hissing sound as air escaped. It only occurred to me afterwards that this may have been a pressurised tank and I may have stuffed it up by opening it. Anyone tell me if I have made a mistake here please? (Backstory: an old drott / crawler operator who does not have the time to do the job for me dropped off his machine here and cheerfully told me to get on with the job myself. My amount of training: zero. My time on a drott at that point: 0 minutes! Off he went, and I've been on my own since then .... )
Do not worry. The pressure builds on it's own from the fluid heating up. Case ran a lot (still do) of pressurized hydraulic reservoirs. On the older TLBs they used the reservoir as an air tank for the brake system. Screw the cap back on and get to work.
Thank you, Shimmy! :notworthy
Follow up question, I notived that the machine is now leaving streaks and pools of some sort of fluid, sort of watery brown in color. Took some photos of the sump and it does not look good ... the sump plates are attached by only a few bolts and the fluid is seeping from between them. Anyone comment?
That's not really a sump persay but a steel pan to protect the underside, lines, hoses etc. From being damaged by rocks, stumps debris , etc. We called them Belly pans. It's heavy so a floor type jack works best with some help. Drop the pan and see where the leak is or what hose you blew. Tom
A helper can be useful as well, as would be a short spud wrench. I'm not sure what you can see from up above but everything runs downhill, it might just be engine crankcase condensation. Often on older machines, folks will strip out bolts on the skid plates and just leave them out, also might mean someone was in there fixing something. Keep your machine properly supported while underneath, I have a small dozer and I'll put it up on 6x6 timbers to gain six inches underneath. Sometimes helps.
Here is a thread dealing with broken or missing bolts under my old 941 Loader, both on track frame inside & the belly pans underneath the machine. No pictures of the belly pan repair but there were several missing/broken bolts to repair. HeavyEquipmentForums
Case uses a 5/8 by two inch bolt on the lower belly pans, some have a shoulder made on them and others us a flat washer. The frame has a small cage on the top that holds a square 5/8 nut that slides into the cage with a tang bent down to hold it in place. You will find nuts welded to the frame, tee bars made to hold bolts dropped down from the top when they did not have the right hard ware to go back with. The pans look like they have material in them and should be serviced, removed, cleaned out and replaced to prevent unwanted material from entering that area of the machine. Those pans are not cheap and loosing one or bending one, having it it turned and forced up into that area could be costly. The other issue with a loose pan it allows material to be packed and pushed up into tubes/lines and sump filter in that area. Some tubes will end up with pin hole leaks do to material packed around them and rusting. I know it's not your machine but i would try and pick up some bolts and tighten that pan up. The machine only has two floor plates which can be remove to see down in there, the left comes up after removing several bolts and the rt you have to unpin engine speed rod cotter key and remove the small clevis pin behind the pedal. Like said, park it on some RR ties and use a floor jack to help you if needed, they can be very unstable even on a jack and slide off under the machine with you causing injury to yourself or others.
I'm pretty sure these machines leaked when new, too many hoses, pipes, connections, whatnot to keep tight. The hydraulics have peep sights on the right side, the torque converter has a dipstick under your right foot when sitting in the seat. If the oil is just running out, you're going to have to do some fixing. These pans like to collect water, too, like fast_st says. Could be that, but it should quit after awhile.