520 oil leaks

[mikes520]

Hey y'all,

I've got a fairly new to me bobcat 520. It's been good for snow removal and such. I like the size, better than the 316 I used some years back.

with a fair amount of hydraulic leaks which I haven't tracked down. One of the major ones is leaking on the back right wheel. There might also be one near the engine, a fair amount of oil in the floor of the engine area.

Where does one start?

Also, any recommended maintenance items otherwise? Looks like the previous owner did change engine oil and hyd. filters, but probably not more maintenance than that, by the looks of things.

 

[mrbb]

I weld start with a good cleaning,I'd remove as many covers and skid splates as possible remove heavy dirt and such while dry or best you can, and then
soak with some good de greaser, and hose off, and then clean better as needed,

from there run machine a little till up to operating temp, then shut off, and start looking for fresh fluids and back track till you find leaks, with MOTOR OFF< as you do NOT want to find leaks with pressure pushing fluids out, as they can do damage to you that way!
while things are clean too, before starting, is a great way to get a good visual opn all things and check conditions and find worn hoses and such , which you can then replace before they fail!

 

[mikes520]

Thanks @mrbb , that's a helpful rundown.

I didn't get much time to dig into it yet, unfortunately. So the machine sat still basically all summer. I started it yesterday and the hydraulic oil was so low that the bucket would tilt, and nothing more than that.

In March, I put 5 gallons of hydraulic oil in it!

The most obvious leak is on the right side, both wheels are super oily. Are there more common leaks in this area? If it's seals/orings etc, is that something for the specialist to fix?

 

[mikes520]

Thanks @mrbb , that's a helpful rundown.

I didn't get much time to dig into it yet, unfortunately. So the machine sat still basically all summer. I started it yesterday and the hydraulic oil was so low that the bucket would tilt, and nothing more than that.

In March, I put 5 gallons of hydraulic oil in it!

The most obvious leak is on the right side, both wheels are super oily. Are there more common leaks in this area? If it's seals/orings etc, is that something for the specialist to fix?

I'm assuming the axle seals are leaking on that side, probably common?

The question is, do they leak chain case oil? Or is it a combined system with hydraulic and chain case using the same fluid?

 

[trobbl]

I weld start with a good cleaning,I'd remove as many covers and skid splates as possible remove heavy dirt and such while dry or best you can, and then
soak with some good de greaser, and hose off, and then clean better as needed,

from there run machine a little till up to operating temp, then shut off, and start looking for fresh fluids and back track till you find leaks, with MOTOR OFF< as you do NOT want to find leaks with pressure pushing fluids out, as they can do damage to you that way!
while things are clean too, before starting, is a great way to get a good visual opn all things and check conditions and find worn hoses and such , which you can then replace before they fail!

I agree completely with a good deep clean before trying to look for the leak. I've been chasing and fixing leaks on my 530 for the past couple years and it would have been impossible without first cleaning things up. I had a hydrostatic pump leak that I ended up pulling the engine to get access. I've also fixed all three hydraulic cylinders and an axle seal. The hydraulic cylinders were by far the easiest to fix.

 

[mikes520]

I agree completely with a good deep clean before trying to look for the leak. I've been chasing and fixing leaks on my 530 for the past couple years and it would have been impossible without first cleaning things up. I had a hydrostatic pump leak that I ended up pulling the engine to get access. I've also fixed all three hydraulic cylinders and an axle seal. The hydraulic cylinders were by far the easiest to fix.

Mines so oily, cleanup would be a project in and of itself.... Probably half to 3/4 inch of oil in the engine bay, oily wheels on right side, oily left hydraulic cylinder, dripping aux couplers.

I do need to clean it up, for sure, but was hoping to fix a big leak and move on to smaller leaks later.

The engine bay to me seems like seals on the pump, but could be reservoir and or lines/hoses near the pump. The two right side axle seals are probably shot, and the left side cylinder and aux couplers are probably orings?

I've got the service manual and found a few YouTube videos where a fella repairs a few of these things on his 530. Any other references?

I'm pretty handy overall, but it's a bit daunting though, always fearful of opening hydraulic systems for repair.....

 

[trobbl]

I've posted a bunch of my repairs on my YouTube channel (The Toolman). I understand even a thorough cleaning might be a big deal. You might be able to get by with reaching in and wiping down any suspect components you can reach. Then refill the hydraulic oil, grab a really good flashlight and start watching for leaks.

Good luck on your repairs. As an owner of a similar machine, you have my sympathy as you go into the tight quarters.

 

[mikes520]

Ahh, I think it's your videos I've been watching... Awesome job on those, thanks for doing them!

 

[mikes520]

Ok, so I added about 4 gallons of ISO 46 fluid and ran it a bit. Wheels seemed sluggish, so I checked the top petcock and added about another quart. It still seemed slower than I remember, and the hydraulics growled a bit when operating them. Is ISO 46 a bit thick and needs more warming up? It's about 30 degrees here today.

Cleaning is next, when I clear a spot in the garage.

 

[trobbl]

The service manual for the 520, 530 and 533 calls for 10W-40 SE for the hydraulic system. They recommend going to 5W-30 when the starting temp is below -10F. I've always had my 530 in a garage heated to 45F in the winter, so I can't comment on how the hydraulics sound or behave when starting out in colder temps. The ISO to SAE chart says ISO 46 is equivalent to 15W or 20W, so you may be right about having to warm it up a bit in colder weather before it can flow well.