Changing Hydraulic Fluid Rev. C

[Gadgetnut]

Want to replace rev. C. hydraulic fluid. Owner's manual says to remove drain plug on hose coming from hydraulic reservoir, did that. Six gallons drained out; how do I flush out the remainder of the old hydraulic fluid -- dealer says capacity is ten gallons. I have the rear bed lifted & propped up with the safety strut now for engine access-- with the bed lift cylinders extended, for hydraulic fluid drain is this a problem?

 

[radman1]

Haven't heard from you for a while. The amount of hydraulic oil needed for an oil change is much less than listed for the amount of oil in the system. My D series (5610) holds about 10 gallons, but the reservoir is listed at 3.7 gallons at the sight glass. Yours is probably similar. My Bobcat skid steer is the same way. Only a portion of the oil is removed with hydraulic oil changes. A lot of oil remains in the pumps, hoses, cylinders etc. I would just recommend changing it at the suggested intervals and it will be fine.

At least your C is much easier to change. On mine, the manual recommends using a hose to siphon the oil out of the reservoir with a hose from the top. I did it and it was slow. Overall, a poor way to drain the oil. Next, time I will probably buy a cheap, little pump that can fit onto a drill and remove it that way.

Bobcat recommend hydraulic oil change at 100 hours then 500 hour intervals. On my big ag tractors, recommended interval changes is around 1000 hours. Depending on the tractor, it may require 50-75 gallons of hydraulic oil.

 

[Gadgetnut]

Thanks for the input. Just replacing the six gallons from the reservoir would certainly be easier. Dealer told me hydraulic oil not usually changed until 1000 hours but my oil looked really dirty, maybe a little "milky" which I read might mean water in the oil. I would strongly like to replace as much of the hydraulic oil as possible-- don't know if I would have to disconnect hydraulic hoses front and back to drain more oil and if so, then bleed the air out of the refilled system to get it going again?? The oil does not smell "toasted" to me, for whatever that's worth. I ran a strong magnet thru the drained oil and filter and did not come up with any metal shavings, nor do I feel or see any.

I'm about half way thru my 500 hour service. Changing the case filter and the hydraulic filters were pretty easy; air filters very easy. I'll change the fuel filter tomorrow. I have a belly pan protective cover with a round hole just big enough for the fuel filter-- hoping my hand or a strap wrench will fit up there to get that filter to unspin. Does diesel fuel pour out wildly when you remove that filter? I guess I'll have to remove the seat to pump that bulb to bleed the air out of the fuel lines-- that happened once before when I ran out of diesel and it took me a long time to find the way to bleed the air! I also have a new cap for the hydraulic reservoir and a new radiator cap.

Here's the monkey wrench though: the engine oil filter had been last changed by my Bobcat dealer and they must have put it on really tight. I tried to spin off the oil filter with both my hands. Wouldn't budge. The turning directions were still printed on the filter so I know I'm turning it the proper way. Moved on to a strap wrench, then with a channel lock filter wrench, then pierced the filter with a large screw driver to get more leverage. Still won't budge. Hit it lightly with a hammer, sawed off half the filter and sprayed PB blaster on the threads. Will continue to work on this by dissecting and removing the old filter piece by piece. This has taken a couple hours and has been quite an aggravation.

 

[radman1]

When you change the fuel filter, completely fill the new filter with diesel. This is very important. It will save a lot of pumping to remove the air. On most of my tractors, if I do this, no priming is required. Start the engine and rev it slightly. May sputter a little or not at all. May not need to prime at all. Haven't tried it with the TC.

You will not loose much fuel when changing the filter - usually just spill a little from the filter.

IMHO, every dealer or mechanic over tightens oil filters. My rule is to tighten as much as reasonably possible with just one hand. So far no failures. The tool I like to use best for changing oil filters is one, where the tool fits over the end of the filter and a socket wrench goes in the end. This allows good torque to remove the filter. Some of these are adjustable and fit different sizes of filters. This kind won't work if there is not enough room for the tool or to turn the socket wrench. The strap type tool and socket wrench has never failed me, the the filters are sometimes crushed and the mechanical advantage of the torque with the socket on the side of the filter is less than optimal.

 

[Gadgetnut]

Yee haw.

 

[radman1]

You did it! I have never seen an oil filter so destroyed. I don't think that is reuseable.

 

[Gadgetnut]

Ha-ha, rad, you said it!!! That filter may be toast, but I think I'll keep it for awhile as a souvenir and to remind me to oil the gaskets well and not to tighten the snot out of them in the future. The photo by the way doesn't have the proper angle to show the 3/4" of bend we put into that thick U-Bolt getting that filter to come loose.

Today's other challenge: checking the axle lubrication level front and rear. You're supposed to back out some bolts then put your finger inside to detect if the reservoir is full enough. Let's just say the bolts looked painted over black, they're also tight as heck and there's no room to get a wrench, socket or any leverage. But persistence paid off and we got them off and both were about overflowing with lube-- but now I know.

Now the 500 hour service is finished! I celebrated with a 27 point lubrication and pressure wash for the ToolCat and similarly for myself a 3 olive martini and a long hot shower. All told, this 500 hour service took me and my helper about a day and a half, including the stuck oil filter, which took a half day. Dealer quoted me $250 for this labor. But now I know how to do it, I know it is done right, and next time it shall be easy.

By the way, rad, your idea of pre-filling the new fuel filter with diesel first (to reduce the air in the lines) really worked. A small cough at start up and away she went. You should know I thought of you this afternoon, and I thank you for your input. Worked like a charm.

I'd like to add that I had never changed the oil in anything before today. The support of this community and the good photos in the owners manual gave me the confidence to want to try something new. Thank you, all.

 

[radman1]

I thought your use of the U bolt was a great idea. Ingenuity strikes again. I hope I never get to the point of needing to use that trick.

Glad the diesel filter went well for you. I don't see how the shop labor rate would be $250 but that's the way it is. You can buy a lot of martini's for $250.

 

[rownow]

If you think you have contamination of fluids, you should get them analyzed before the problem gets worse. Then you might fix the source of the problem.

Bobcat has a analysis program, though I know nothing about it.
Bobcat Oil Analysis Program - Bobcat Company

Blackstone-labs tells me that they will do oil analysis on hydraulic fluid as well as engine oil. Costs about $20 for a basic test.

Blackstone Laboratories - What is Oil Analysis