Kubota M7040F odd rod in hydraulic fluid flow path.

[Skot]

Working on my new but very old Kubota M7040‑series tractor, serial number 10468, which puts it in the early production range, likely 2007–2008 by my swag. I suspect it may be a hydraulic‑block features that was removed or redesigned in later years and no longer appear in current parts diagrams? Or that is my working theory..

While changing hydraulic fluid, I found a part that does not appear in any modern Kubota diagram.

Inside the hydraulic filter housing, there is a solid steel rod protruding through the center of the threaded fitting labeled 32590‑38330 (JOINT, SCREW). This rod:

• is completely fixed (does not move under pressure or by hand)
• is strongly magnetic
• is covered in fine ferrous dust and small shiny needle‑like metal particles
• does not match any part shown in current M7040/M7040F hydraulic diagrams

I suspect it is a early rev of the filter magnet that now listed as a doughnut magnet (T0070-37720) that fits inside the filter base? But so far have not been able to find any details on it. There was no doughnut magnet when I removed the old filter. Its been running like this for a number of years.. So trying to make the call, is this good enough, or do i need to order the doughnut?

Was pointed out on another board, where I started at today, that this rod/magnet placement is in the outflow from the filter not the intake? which is very odd design if in fact I am correct about this? Would also explain why they changed it to the doughnuts?

I’m posting to see if anyone with an early‑serial M7040 (sub‑15000) recognizes this fixed magnetic rod, and if there are any recommendations on, adding the doughnut magnets before I add in the liquid gold SUDT2 hydraulic fluid i decided to start with, as i was not sure what it had in it before?

 

[whitetiger]

 

[North Idaho Wolfman]

And Ta-Da, you have your answer!

 

[PoTreeBoy]

View attachment 177331

Seems odd that only one filter has a magnet. Aren't they in parallel?

 

[North Idaho Wolfman]

Seems odd that only one filter has a magnet. Aren't they in parallel?

The magnetic rod is in an interal path that is shared by both filters, the fluid has to pass the magnet before it gets to either filter.

 

[Dustyx2]

The magnetic rod is in an interal path that is shared by both filters, the fluid has to pass the magnet before it gets to either filter.

I'm failing to understand this. In an ordinary filter application oil flows from the outside of the filter element to the inside and exits the center hole. In this case past the magnet. Is the flow reversed in this application? How is this magnet "shared" when it is only in the inlet or output path of this one filter. Certainly an odd configuration to me. Certainly not saying you're wrong.

 

[GeoHorn]

The filter Media captures large objects….the magnetic rod captures anything so-fine as to have passed thru.

Clean it off …. reinstall. Do not “add” another magnet of the “flux” may conflict/counteract.
IMO

 

[Dustyx2]

The filter Media captures large objects….the magnetic rod captures anything so-fine as to have passed thru.

Clean it off …. reinstall. Do not “add” another magnet of the “flux” may conflict/counteract.
IMO

I believe this would be the first time I've seen a magnet in filtered oil flow. I think it would be preferred pre filter.

 

[GeoHorn]

I believe this would be the first time I've seen a magnet in filtered oil flow. I think it would be preferred pre filter.

Agreed …(as to theory)….. but, ….what do you suppose occurs with magnetic sump plugs..?

A magnet in either flow is preferable to none, IMO.


<edit> I’m thinking that a magnet downstream of the filter media…will capture what is so fine…the media missed it…. While a magnet pre-media may become over-whelmed before the filter is changed-out… ?? (larger pieces may block the magnet from attaching the finer particles..?? just exercising my over-active imagination..)

 

[North Idaho Wolfman]

I believe this would be the first time I've seen a magnet in filtered oil flow. I think it would be preferred pre filter.

This was a very short lived and limited design concept, it was quickly replaced by the magnets in newer designs.

 

[North Idaho Wolfman]

Working on my new but very old Kubota M7040‑series tractor, serial number 10468, which puts it in the early production range, likely 2007–2008 by my swag. I suspect it may be a hydraulic‑block features that was removed or redesigned in later years and no longer appear in current parts diagrams? Or that is my working theory..

While changing hydraulic fluid, I found a part that does not appear in any modern Kubota diagram.

Inside the hydraulic filter housing, there is a solid steel rod protruding through the center of the threaded fitting labeled 32590‑38330 (JOINT, SCREW). This rod:

• is completely fixed (does not move under pressure or by hand)
• is strongly magnetic
• is covered in fine ferrous dust and small shiny needle‑like metal particles
• does not match any part shown in current M7040/M7040F hydraulic diagrams

I suspect it is a early rev of the filter magnet that now listed as a doughnut magnet (T0070-37720) that fits inside the filter base? But so far have not been able to find any details on it. There was no doughnut magnet when I removed the old filter. Its been running like this for a number of years.. So trying to make the call, is this good enough, or do i need to order the doughnut?

Was pointed out on another board, where I started at today, that this rod/magnet placement is in the outflow from the filter not the intake? which is very odd design if in fact I am correct about this? Would also explain why they changed it to the doughnuts? View attachment 177319 View attachment 177320

I’m posting to see if anyone with an early‑serial M7040 (sub‑15000) recognizes this fixed magnetic rod, and if there are any recommendations on, adding the doughnut magnets before I add in the liquid gold SUDT2 hydraulic fluid i decided to start with, as i was not sure what it had in it before?

If it's bugging you, you can change it to the newer design, just unscrew the rod out of the case and use the newer ring magnets.

Old design:


New design:

 

[Dustyx2]

Agreed …(as to theory)….. but, ….what do you suppose occurs with magnetic sump plugs..?

A magnet in either flow is preferable to none, IMO.


<edit> I’m thinking that a magnet downstream of the filter media…will capture what is so fine…the media missed it…. While a magnet pre-media may become over-whelmed before the filter is changed-out… ?? (larger pieces may block the magnet from attaching the finer particles..?? just exercising my over-active imagination..)

I thought about noting that but didn't think it would be necessary. A bit of a different scenario I would say. (as in not in the filtered stream of flow)

I see you edited as I was replying. Agree.

 

[GeoHorn]

Well….it’s certainly a good indicator of whatever your filter-choice misses.

I have read dissertations by so-called “experts” …who state that the ”smudge” captured by magnets is So Fine…as to pose Zero harm to the engine.

That may be true…. but I still stick magnets on the outside of the filter-can on some of my equipment. Has it ”saved” me from expensive engine repairs..? Not that I can tell… but it keeps me curious.

(The only filters I religiously cut-open for inspection are on personal airplanes…. as a “preventive / detection” action. I’ve never found anything except carbon particles (likely from the undesides of piston-crowns)…. however, I’ll post a pic of a discovery one of my colleagues discovered, captured by the media, and asked an opinion about…. No where in that engine model is a toothed lock-washer used…..so the discussion centered around spin-on-filter-manufacturing…I.E. “where did this come from?” )

 

[GeoHorn]

On a follow-up discussion (re: things found in filters): I once flew a man and his guest to Dallas Love Field (DAL) from AUS in a ”new to him” twin Cessna. It was his first flight use of the airplane he’d recently purchased.
Enroute, I noticed the left engine oil pressure was indicating 5 psi …(it should have been 50-60)….
So they wouldn‘t panic more than necessary, … I briefed the pax I would be shutting down that engine as a precaution…. and did so.

We descended into the Dallas area and competed an ILS approach to DAL and landed.

Unable to taxi on one engine (and ATC having “dropped the ball” failing to notify the Fixed Base Operator (FBO) we’d need to be towed-into the ramp area….. we were blocking the taxiway…so I re-started the left engine…and, Wouldn’t you know-it….the oil press came up to 50 psi.

Discharged the pax, we had the mx facility pull that engine filter and found it FULL of pink-colored plastic particles about the size of rock-salt. The engine pressure-relief-valve was also blocked Open…by some of that stuff.

Turns out the engine-oil mfr’r had suffered a packaging-equip’t failure at the refinery…. a plastic gear that pumped freshly-refined oil into 1-qt containers….. had disintegrated at the refinery… and all those pink plastic particles was from that event.

Apparently, as the filter became overwhelmed by the plastic, the filter By-pass valve opened and allowed that junk to pas—on…. and jammed the engine press-relief-valve to the “open” position…resulting in very-low oil pressure.

Moral: Not all contaminants are necessarily from engine defects. Your oil supplier and filter mfr’r can contribute to problems also.

 

[Skot]

I'm failing to understand this. In an ordinary filter application oil flows from the outside of the filter element to the inside and exits the center hole. In this case past the magnet. Is the flow reversed in this application? How is this magnet "shared" when it is only in the inlet or output path of this one filter. Certainly an odd configuration to me. Certainly not saying you're wrong.

This would be the basic question that was spinning in my brain.. If my SWAG was correct, it did not make much since? When I am guessing and it it does not make since, then my general assumption is I am missing something.. So i keep looking.

But at the same time, if i was right, then they changed the design for a reason.. Not knowing what that reason was was was bugging the hell out of me.. I did not want to find out later and have to dump the SUDT2 and start over. it made me cry to buy it the first time..

It turns into circle of never ending questions, that still makes my head hurt.. So i finally flipped a coin.

My Final answer: Add the 2 disk magnets to the filters and leave the rod magnet in place..

 

[whitetiger]

This would be the basic question that was spinning in my brain.. If my SWAG was correct, it did not make much since? When I am guessing and it it does not make since, then my general assumption is I am missing something.. So i keep looking.

But at the same time, if i was right, then they changed the design for a reason.. Not knowing what that reason was was was bugging the hell out of me.. I did not want to find out later and have to dump the SUDT2 and start over. it made me cry to buy it the first time..

It turns into circle of never ending questions, that still makes my head hurt.. So i finally flipped a coin.

My Final answer: Add the 2 disk magnets to the filters and leave the rod magnet in place..

Make sure the magnets do not keep the filter seal from compressing onto the housing when you screw the filter on. Guess how I know this can happen? It was not the same model as yours, but I would put a magnet on the filter and lay a straight edge across the seal side to side.

You could just use the later filters which come with magnets and will seal.