50 hr filter change, added a restriction indicator

[m5040]

Did my first 50 hr hydraulic filter change and while I had it off, I drilled and tapped the suction side of the filter housing for a restriction indicator. Kind of a disappointment because it is just about out of the green (acceptable) area with the brand new filter, 70 deg oil and engine at idle. It goes up to half scale (red=restricted) when you raise the engine RPMs up to a above normal (for me) speed.
I bought the gauge from a filter manufacturer which was supposed to be for the suction side of a hyd system.

So if anyone thinks it is worth doing this you may want a higher scale gauge and also liquid filled (because it flutters at times).

The reason to have a indicator is once you build a history of how it acts, you can tell when to change your filter, or if something is going wrong in the hyd system and inducing contaminants which plugs your filter early.

the pic with the lowest reading is at idle, oil temp 70 deg.
the pic with a higher reading is a low working speed, temp 70 deg
The other pic shows the general area.

 

[Roadworthy]

I'm guessing what you've got there is some type of pressure gauge - low pressure. Are you sure it's installed in the correct location? I mean is the so called suction side of the filter actually suction or is it still carrying some pressure as it returns through the filter?

 

[m5040]

On Power trac the hyd filter is on the suction side. The filter is in series in the line that goes from the bottom of the hyd reservoir to the inlet of the pump. It is always a vacuum. If you look close on the filter housing, there are 2 divots, one toward each opening (inlet/outlet). You can see one divot in my last two pictures. The divots are the position the engineers of the filter housing want to be used as mounting points for indicators/gauges. If I were to use the other divot (inlet side), it would only measure the vacuum necessary to draw the hyd oil up to the inlet of the filter housing. It would only change due to temp and oil viscosity, and the condition of the filter would have no bearing on the reading. I used the outlet divot and therefore it registers the "vacuum necessary to draw the hyd oil up to the inlet of the filter housing" plus the vacuum necessary to draw it through the filter housing and media. As the media gets contaminated the amount of vacuum will rise. Trucks with diesel engines typically have a similar device on the air filter housing. On those it locks in place to register the highest reading (because you can't be there to see it when driving as it will get the highest reading when the engine is at peak HP/torque). Hope this helps. A QUICK NOTE, IF YOU TRY THIS KEEP EVERYTHING SUPER CLEAN, TAKE THE HOUSING OFF AND WASH IT AFTER DRILLING AND TAPPING.

 

[marrt]

I've argued before the viscosity of the motor oil selected by Power Trac is too high. For example, if you have a Sauer Danfoss Series 40 pump, the recommended continuous inlet pressure is no less than 6.3 inches HG vacuum. Max cold start is 9.2 inches Hg vacuum. Looks like you right on the limit, which is also what your gauge is showing.

That said, 70 degrees isn't very warm for hydraulic systems (even though this is a multi-viscosity oil). It would be interesting to see your reading at cold start and at say 170-180 degrees on the oil. Those are the more interesting readings.

Kubota, for example, requires a 15+ minute warm up if it's freezing or below. They want the oil warm before the tractor is used to avoid cavitation issues.

 

[m5040]

That morning I ran the machine for a hour to warm up the oil with the thought it would be easier to bleed. It would have been a quick change, but after I drilled and tapped the housing I couldn't clean the chips out satisfactorily, so I took the housing off to wash it out. By the time I finished it all up, the oil dropped to the 70 deg figure and I included it to give a better idea of what was going on. A liquid filled gauge is really needed, if my gauge survives, I will update with figures at high temps.

 

[woodlandfarms]

While it would be great to monitor every circuit, the only gauge I really long for is a decent oil level gauge for the hydraulic tank. Too many close calls with ruptured hoses in my many years of ownership. If not a gauge at least a warning siren.

 

[SpringHollow]

Plenty of room on the tank cover to add such items. Since we are spending your money, get a laser or ultrasonic one for $1-2K.

Perhaps this one stuck inside a tube with an open bottom
Amazon.com: Genuine Marine 12V/24V Water/Fuel Tank Level Sensor, 24-33 ohms, 7.5 Inch, 316 Stainless Steel, Resistive S5 Liquid Level Sensor Sending Unit for RV,(2mm with Gasket (1Pcs) and Screw (5Pcs)): Automotive

Ken

 

[MossRoad]

GM cars have a low oil sensor in the pan. It's about $25 at Autozone. Just a two wire lead. I wonder if the oil tank could be tapped down about half way (inside the tub to protect the switch) and one of these used? Don't know anything about the sensor itself. On/off or resistance. But it looks like a little float on a horizontal stick. Just a thought.

 

[m5040]

I don't know, by the time the oil level drops to your predetermined area (which you would have to put low enough so the alarm doesn't keep coming on when you go on a side hill or up/down hills {and with a hyd pistons extended that lower your level}), the spraying oil would have made a big mess and should be noticeable on its own.

 

[MossRoad]

I don't know, by the time the oil level drops to your predetermined area (which you would have to put low enough so the alarm doesn't keep coming on when you go on a side hill or up/down hills {and with a hyd pistons extended that lower your level}), the spraying oil would have made a big mess and should be noticeable on its own.

I mow 2+ miles of trails and never turn around until I get to the return point and go for a 2nd pass to make them 7' wide. That's when I'd notice it. However, using the loader or mowing the lawn, yep, I'd see it the next time around.

I think if you mounted it towards the center of the tank just to one side or the other of the tunnel, it would be OK.