743 after-market hydraulic fluid filter

[jimhumphries]

Any recommendations for brands/model numbers of hydraulic fluid filters that are drop-in replacements for the Bobcat-branded filter in a 743? Also, has anyone had any experience (good or bad) using a water absorbing filter like the Donaldson P561183? Taking that one step further, does anyone know of a drop-in, water absorbing, hydraulic fluid filter for a 743 (I have a 743 that sits outside in the California high desert for long periods between uses and that has developed "milky" hydraulic fluid). - Jim

 

[skidsteer.ca]

I have heard of water separators for fuel but not for oil. Once it gets milky the only thing I know you can do is change it. It may require more then one change to because the reservoir only holds @ 50% of the volume. I'd try to crack the cylinder lines and get as much as possible out of them too, and any other line you can get at, along with the filter.
While your at it better check your chain case too as its more common to get water in there then the hydraulics.
Are you sure there isn't a crack in the reservoir or the cap is somehow leaking. The moisture must be getting in somehow. Also don't forget the attachments.
As for other filter brands the Bobcat # can be cross to most any of the major brands.
Ken

 

[Tazza]

I have heard of water separators for fuel but not for oil. Once it gets milky the only thing I know you can do is change it. It may require more then one change to because the reservoir only holds @ 50% of the volume. I'd try to crack the cylinder lines and get as much as possible out of them too, and any other line you can get at, along with the filter.
While your at it better check your chain case too as its more common to get water in there then the hydraulics.
Are you sure there isn't a crack in the reservoir or the cap is somehow leaking. The moisture must be getting in somehow. Also don't forget the attachments.
As for other filter brands the Bobcat # can be cross to most any of the major brands.
Ken

Ensure the gasket on the filling cap is good too, if its bad or missing you will get water in here if its left outside.

 

[jimhumphries]

Ensure the gasket on the filling cap is good too, if its bad or missing you will get water in here if its left outside.

Ken/Tazza: Thanks for the advice. The attachments haven't been connected yet so I think they are "clean". I ordered a new breather cap and gasket and will look closely at the reservoir for cracks. My 743 doesn't have the same filter head as the one shown in my maintenance manual. The one shown has the mounting lugs as part of the casting (no additional bracket). Mine uses a bracket. In fact, I just replaced the bracket. The original was welded directly to the engine compartment side-wall (it was a straight plate) and it had cracked near the filter head so the whole filter assembly was loose in the compartment. The new bracket (from Bobcat) has a 90 deg bend and it bolts to the side-wall. I installed that after removing what was left of the old bracket with a sawsall and grinder. I would like to give an absorbing filter a try before I replace the 6 gallons of fluid in the system but I don't know what the pressure/collapse rating should be. I would use the specs for the original filter as guidelines but I haven't found that data yet (hence, the question about brand and model for a drop-in replacement). - Jim

 

[Fishfiles]

Ken/Tazza: Thanks for the advice. The attachments haven't been connected yet so I think they are "clean". I ordered a new breather cap and gasket and will look closely at the reservoir for cracks. My 743 doesn't have the same filter head as the one shown in my maintenance manual. The one shown has the mounting lugs as part of the casting (no additional bracket). Mine uses a bracket. In fact, I just replaced the bracket. The original was welded directly to the engine compartment side-wall (it was a straight plate) and it had cracked near the filter head so the whole filter assembly was loose in the compartment. The new bracket (from Bobcat) has a 90 deg bend and it bolts to the side-wall. I installed that after removing what was left of the old bracket with a sawsall and grinder. I would like to give an absorbing filter a try before I replace the 6 gallons of fluid in the system but I don't know what the pressure/collapse rating should be. I would use the specs for the original filter as guidelines but I haven't found that data yet (hence, the question about brand and model for a drop-in replacement). - Jim

I have used the water absorbing filters a few times before , I could get you a number from my donaldson dealer Monday , my thoughts on them , they are expensive , it usually takes two or even three filter changes before it gets it cleared up , I think it's better on a small machine like a 743 to change the oil several times , it will still be milky but after running the machine for a while it will evaporate out

 

[Tazza]

Ken/Tazza: Thanks for the advice. The attachments haven't been connected yet so I think they are "clean". I ordered a new breather cap and gasket and will look closely at the reservoir for cracks. My 743 doesn't have the same filter head as the one shown in my maintenance manual. The one shown has the mounting lugs as part of the casting (no additional bracket). Mine uses a bracket. In fact, I just replaced the bracket. The original was welded directly to the engine compartment side-wall (it was a straight plate) and it had cracked near the filter head so the whole filter assembly was loose in the compartment. The new bracket (from Bobcat) has a 90 deg bend and it bolts to the side-wall. I installed that after removing what was left of the old bracket with a sawsall and grinder. I would like to give an absorbing filter a try before I replace the 6 gallons of fluid in the system but I don't know what the pressure/collapse rating should be. I would use the specs for the original filter as guidelines but I haven't found that data yet (hence, the question about brand and model for a drop-in replacement). - Jim

The water absorbing style filters will only remove SMALL amounts of water contamination. I had a machine that had a slight while colour in the oil, i had to change the oil about 4 times to get it to a state i was happy with. After the changes you can use a filter with desiccant (spelling) to remove any more water that may still be in there. As for pressure, your system should be no higher than say 200 PSI, your charge relief is set to about 95.

 

[jimhumphries]

The water absorbing style filters will only remove SMALL amounts of water contamination. I had a machine that had a slight while colour in the oil, i had to change the oil about 4 times to get it to a state i was happy with. After the changes you can use a filter with desiccant (spelling) to remove any more water that may still be in there. As for pressure, your system should be no higher than say 200 PSI, your charge relief is set to about 95.

Tazza/Fishfiles: I think it is a Donaldson P560584 but I would sure appreciate it if you could confirm that. This would be for a 1987 model 743, SN 5019-M-31381. It sounds like I should plan on replacing the fluid as well (and maybe a few times). I'm guessing this will run about $70 per change-out? - Jim

 

[Tazza]

Tazza/Fishfiles: I think it is a Donaldson P560584 but I would sure appreciate it if you could confirm that. This would be for a 1987 model 743, SN 5019-M-31381. It sounds like I should plan on replacing the fluid as well (and maybe a few times). I'm guessing this will run about $70 per change-out? - Jim

Sorry, i don't have a cross over to know just what filter you need. The big difference is the thread, i have been caught before when i got an after market filter and the thread was wrong but they did exchange it for free.

 

[jimhumphries]

Ensure the gasket on the filling cap is good too, if its bad or missing you will get water in here if its left outside.

I replaced the breather cap and gasket. There was no gasket under the old breather cap. Thanks for the advice.

 

[jimhumphries]

I replaced the breather cap and gasket. There was no gasket under the old breather cap. Thanks for the advice.

OK - From what I can tell the drop-in replacement for the Bobcat PN 6598903 filter (but with water absorbing media) is a Donaldson P560584. It looks like this one will replace the Bobcat filter both physically and in terms of performance. Price is around $50.00 US from Applied Industrial Technology. After I get the water out I will probably throw one of these in for good measure. Here's my plan for the next step and I know it runs counter to some good advice (I'm just hard-headed and determined to provide some good entertainment for you seasoned guys). I got a deal on some Donaldson P561183 water absorbing filters (ten filters for $8.00 US, each). These things are supposed to absorb up to 3/4 of a quart of water (0.7 liter) before they're saturated so before I commit to dumping 18 quarts of 10W-30 (dump existing, flush twice, 1 replacement) I built a rig to run the oil through one of those filters off the auxiliary ports of my 743 (hence the question about the flow direction on these ports). A picture of the rig is at http://i414.photobucket.com/albums/pp225/jimhumphries/Bobcat 743 and Bradco 408/IMG_1896_filter.jpg. There's a manual bypass valve so I can start things off very slowly (the filter head internal bypass valve pressure is factory set to 25 psi). What you see in the picture is about $200.00 worth of hardware or about the price of 3 fluid change-outs so I figured it was worth a shot and, if it works, I can use it whenever I have a water problem. I'll report back after I get a chance to try it. First I have to fix my right-side steering creep problem and I'm not having much luck with that. Jim

 

[Tazza]

OK - From what I can tell the drop-in replacement for the Bobcat PN 6598903 filter (but with water absorbing media) is a Donaldson P560584. It looks like this one will replace the Bobcat filter both physically and in terms of performance. Price is around $50.00 US from Applied Industrial Technology. After I get the water out I will probably throw one of these in for good measure. Here's my plan for the next step and I know it runs counter to some good advice (I'm just hard-headed and determined to provide some good entertainment for you seasoned guys). I got a deal on some Donaldson P561183 water absorbing filters (ten filters for $8.00 US, each). These things are supposed to absorb up to 3/4 of a quart of water (0.7 liter) before they're saturated so before I commit to dumping 18 quarts of 10W-30 (dump existing, flush twice, 1 replacement) I built a rig to run the oil through one of those filters off the auxiliary ports of my 743 (hence the question about the flow direction on these ports). A picture of the rig is at http://i414.photobucket.com/albums/pp225/jimhumphries/Bobcat%20743%20and%20Bradco%20408/IMG_1896_filter.jpg. There's a manual bypass valve so I can start things off very slowly (the filter head internal bypass valve pressure is factory set to 25 psi). What you see in the picture is about $200.00 worth of hardware or about the price of 3 fluid change-outs so I figured it was worth a shot and, if it works, I can use it whenever I have a water problem. I'll report back after I get a chance to try it. First I have to fix my right-side steering creep problem and I'm not having much luck with that. Jim

Interesting setup.... I do understand why you went for the 10 pack of water absorbing filters instead of one or 2 of the correct ones, cheap as!
If it was me, I'd still like to have dumped the oil at least once even though its been filtered and water removed. I'm also wondering if getting the oil hot will help it absorb water or not.
Good luck with it all, I'm sure you will get it all sorted out!

 

[jimhumphries]

Interesting setup.... I do understand why you went for the 10 pack of water absorbing filters instead of one or 2 of the correct ones, cheap as!
If it was me, I'd still like to have dumped the oil at least once even though its been filtered and water removed. I'm also wondering if getting the oil hot will help it absorb water or not.
Good luck with it all, I'm sure you will get it all sorted out!

Tazza: I think you are right about doing the change-out and I think I should do that before I try the filter. That will get rid of most of the water and then I'll know what I have in there. Hopefully one change-out plus filtering will do it. The new breather cap and gasket may also help keep the water out (I didn't see any cracks in the tank). I do know that the fluid wasn't milky when I bought the 743. The guy I bought it from attached a trencher to the auxiliary and clean oil came out when he fumbled with the coupler. This was after running the loader for at least ten minutes so the water problem seems to have developed on my watch. I'll report back one way or the other on the filter results. On to the steering creep problem and I have lots of questions about that! Jim