Case Drain Filters and Tank Filler Screens

[thetool]

Maybe some of you smart hydraulics guys could chime in:
I'm really starting to wonder if the drive motor case drain bronze filter is worth having. Sure, it strains shed particles from the motor before going back to tank, but if this filter gets plugged up it REALLY screws up EVERYTHING.
And the wire filler screen in the neck of the tank? So easily ripped or punctured with a funnel or hose or whatever some stick in there, then it falls into the works and wreaks havoc.
No matter how hard owners try to keep their oil clean, someone less careful will figure out a way to put dirt in the tank. Case drain filters catch it, but plug up quick, cauing major damage for sure. Wouldn't it be the lesser of two evils just to let it go until the main filter catches it? And the main filter has monitored by-pass.
Would it not also be the lesser of two evils to remove the filler screen and let the dirt that it would have caught it go through until it hits the main filter, rather than have the screen come apart and have wire mesh go through the works?
It's such a sad thing to tell someone he needs new pumps and motors.

 

[Tazza]

I always figured every little thing to help keep the oil clean is an advantage. I have never had the bronze screen fall to bits but i have seen them punctured. The case drain filters I'd like to keep there as they are there to filter the oil coming from the drive motors that run the shaft from the motor to the drive chains, i figured you may get metal particles from when these parts wear.
Sure the main filter will catch most of it, but the other filters are your main line of defense BEFORE it hits the pump. The pump is the part I'd rather not have any rubbish in my oil that could possible score the internals of the pumps.
How often do your case drain filters plug up? and how can you tell? i am new to modern machines and would like to know what to look out for.

 

[sterlclan]

I always figured every little thing to help keep the oil clean is an advantage. I have never had the bronze screen fall to bits but i have seen them punctured. The case drain filters I'd like to keep there as they are there to filter the oil coming from the drive motors that run the shaft from the motor to the drive chains, i figured you may get metal particles from when these parts wear.
Sure the main filter will catch most of it, but the other filters are your main line of defense BEFORE it hits the pump. The pump is the part I'd rather not have any rubbish in my oil that could possible score the internals of the pumps.
How often do your case drain filters plug up? and how can you tell? i am new to modern machines and would like to know what to look out for.

info here http://www.hydraulicsupermarket.com/technical.html has a good argument for NO filters.........Jeff

 

[Tazza]

info here http://www.hydraulicsupermarket.com/technical.html has a good argument for NO filters.........Jeff

I remember reading this a while back..... All valid reasons as it shows the damage caused to piston motors with high case pressure. I also like the idea of a transducer on the *pressure* side of the filter to alert you if the filter is being plugged up. This may be something I'll do on my 763.
I know suction line filters can be a real big no no and cause damage if they get plugged up. I guess its something to decide if you want the risk of it causing damage if it was to plug up or possibly causing troubles further down the line. I figure if a motor or pump was to fail it would spread particles throughout the system anyway if there is a filter or not.

 

[thetool]

I remember reading this a while back..... All valid reasons as it shows the damage caused to piston motors with high case pressure. I also like the idea of a transducer on the *pressure* side of the filter to alert you if the filter is being plugged up. This may be something I'll do on my 763.
I know suction line filters can be a real big no no and cause damage if they get plugged up. I guess its something to decide if you want the risk of it causing damage if it was to plug up or possibly causing troubles further down the line. I figure if a motor or pump was to fail it would spread particles throughout the system anyway if there is a filter or not.

Yo Jeff that is a cool site-I started reading and some articles had EXACTLY the info I was wondering about.
I tried to subscribe but it dosen't work......Oh well.
Tazza-I know you have F-series machines and the filter I'm talking about is the bronze filter inside the aluminum housing-I think your models have one for each motor, and in my recollection they weren't much of a problem when these models were current.
Lately, though, with tracked machines especially-they plug up and the motors crash-BOTH of them because both motors I teed into one filter. It's not big enough, and it has no monitoring or transducer to fire something up if it plugs up, and folks don't know until it's too late.
That is a really good site with good info.
I was LMAO at "Start, ya bastard" mentioned earlier. I'd love to get a can of that for a conversation piece. I wonder if they can ship it?

 

[Tazza]

Yo Jeff that is a cool site-I started reading and some articles had EXACTLY the info I was wondering about.
I tried to subscribe but it dosen't work......Oh well.
Tazza-I know you have F-series machines and the filter I'm talking about is the bronze filter inside the aluminum housing-I think your models have one for each motor, and in my recollection they weren't much of a problem when these models were current.
Lately, though, with tracked machines especially-they plug up and the motors crash-BOTH of them because both motors I teed into one filter. It's not big enough, and it has no monitoring or transducer to fire something up if it plugs up, and folks don't know until it's too late.
That is a really good site with good info.
I was LMAO at "Start, ya bastard" mentioned earlier. I'd love to get a can of that for a conversation piece. I wonder if they can ship it?

I know the filters you are talking about, my 751 has 2 of them too. These machines run geroler style motors and not axial piston type, not sure what the track machines run. Its silly that yours only runs one filter, you need to get the case drain oil out with the least restriction. Those filters should have some sort of over pressure by-pass like the main filter does then you wouldn't risk damage when it plugs up. It would be pretty easy to just remove the bronze screens from the alloy housings if needed.
I would doubt they would let you import a can of start you bastard as its rather flammable its a shame, makes everyone laugh when i tell them about it. I remember the first time i heard about it i was like what? are you serious? and he said its really called that! all i had before was CRC aerostart.

 

[thetool]

I know the filters you are talking about, my 751 has 2 of them too. These machines run geroler style motors and not axial piston type, not sure what the track machines run. Its silly that yours only runs one filter, you need to get the case drain oil out with the least restriction. Those filters should have some sort of over pressure by-pass like the main filter does then you wouldn't risk damage when it plugs up. It would be pretty easy to just remove the bronze screens from the alloy housings if needed.
I would doubt they would let you import a can of start you bastard as its rather flammable its a shame, makes everyone laugh when i tell them about it. I remember the first time i heard about it i was like what? are you serious? and he said its really called that! all i had before was CRC aerostart.

Tazza-I came across like you didn't know the filters-of course you do and I apologize!
The tracked machines have a Rexroth radial piston motor with a spring-applied wet friction disc-pak brake, released by charge pressure behind an electric solenoid. If the brake seals fail, often the machine will drive right through the brake without any noise or hesitation.
2-speed wheeled s250 and up have axial-piston motors, with a 2-position swashplate, swashed by charge pressure behind an electric solenoid, and a brake like above. Both models have a single standard case-drain filter servicing both motors.
A while back, we asked BC why they didn't hang a filter on each motor, and they said that it needed equal back-pressure here or it wouldn't track straight. Made sense at the time, especially for the 2-speeders.
A problem is with these two-speed machines, a motor failure plugs the filter, or a plugged filter takes out the motor, either way, unless you know it fast it soon turns into both motors. With the two-speeds, it pressurizes the motor carriers, blows the seals, and fills the chaincase. Those motor carriers have to be removed and disassembled to replace the seals!
This guy I used to work with, a very astute individual(Mark knows who>>LG), experimented on machines of a certain customer who kept blowing up motors and carriers. He plumbed in another filter, one for each motor, and never had a problem with tracking.
I'm thinking of all this stuff and can't help but wonder if it would just be better over all to pull the bronze element after the first 500 hours and leave the filter body open. Not for guys who REALLY take care with oil cleanliness, but maybe as a solution for guys who own more machines, with multiple operators, any of which will top off a tank, some of which may really not care that much.
Maybe I think too much.......=)

 

[Tazza]

Tazza-I came across like you didn't know the filters-of course you do and I apologize!
The tracked machines have a Rexroth radial piston motor with a spring-applied wet friction disc-pak brake, released by charge pressure behind an electric solenoid. If the brake seals fail, often the machine will drive right through the brake without any noise or hesitation.
2-speed wheeled s250 and up have axial-piston motors, with a 2-position swashplate, swashed by charge pressure behind an electric solenoid, and a brake like above. Both models have a single standard case-drain filter servicing both motors.
A while back, we asked BC why they didn't hang a filter on each motor, and they said that it needed equal back-pressure here or it wouldn't track straight. Made sense at the time, especially for the 2-speeders.
A problem is with these two-speed machines, a motor failure plugs the filter, or a plugged filter takes out the motor, either way, unless you know it fast it soon turns into both motors. With the two-speeds, it pressurizes the motor carriers, blows the seals, and fills the chaincase. Those motor carriers have to be removed and disassembled to replace the seals!
This guy I used to work with, a very astute individual(Mark knows who>>LG), experimented on machines of a certain customer who kept blowing up motors and carriers. He plumbed in another filter, one for each motor, and never had a problem with tracking.
I'm thinking of all this stuff and can't help but wonder if it would just be better over all to pull the bronze element after the first 500 hours and leave the filter body open. Not for guys who REALLY take care with oil cleanliness, but maybe as a solution for guys who own more machines, with multiple operators, any of which will top off a tank, some of which may really not care that much.
Maybe I think too much.......=)

Sorry, i didnt mean for it so sound that way, i didn't take any offense and hope you didn't either... As you know i'm new to these machines so its expected that i may not know about them.
I understand why you are concerned with the filters!!! that would be scary having no brake like that......

 

[skidsteer.ca]

Sorry, i didnt mean for it so sound that way, i didn't take any offense and hope you didn't either... As you know i'm new to these machines so its expected that i may not know about them.
I understand why you are concerned with the filters!!! that would be scary having no brake like that......

Seen as Bobcat is such a fan of sending units and like to monitor everything, they should be adding a backpressure warning light, beeper, and shutdown to the list. It would be fairly simple to double up on the filters, or use a larger filter or add a pressure guage or Murphy switchguage to alert the operator.
Ken

 

[ram12v]

Seen as Bobcat is such a fan of sending units and like to monitor everything, they should be adding a backpressure warning light, beeper, and shutdown to the list. It would be fairly simple to double up on the filters, or use a larger filter or add a pressure guage or Murphy switchguage to alert the operator.
Ken

I have been trying to find these case drain filters since I have owned my machines. Anyone know where these filters are located on track machines, 864 and T200? My book says there are two of them. Thanks.

 

[thetool]

I have been trying to find these case drain filters since I have owned my machines. Anyone know where these filters are located on track machines, 864 and T200? My book says there are two of them. Thanks.

Lift the cab, in the center and in front of your pump, and aluminum tube about 4"x1.5", with tees and hoses on both ends.
Remove the hoses, make sure you mark them somehow, and use caps and plugs. The filter housing is clamped down with a strap clamp. Remove it and open it with a 1 1/2" and 1 3/8" wrenches, and there is a bronze element inside. Bobcat has a kit with new element and seals. clean it and replace seals and element, re-install, and you in bidness.
Your second filter is in the left rear, and is in-line with your auxillary case-drain, and is not so critical, unless you've been mega-planing or somethig like that.