Mitsubishi 4D32 diesel power unit in CAT 307SSR

[lantraxco]

There are dessicant breathers available, probably would be a simple matter to plumb one into the vent line on the radiator cap relief valve.

 

[Pants]

OK, I gotta Google THAT now, too...thanks...

Know anything about these? I'm kind of excited about them (the following linked item) as maybe a cure-all for both hydraulic- AND fuel-tank rust issues that seem to be coming at me right and left:
http://b3cfuel.com/products/diesel-tank-snake-water-absorber
These even have magnets built in, so maybe I won't have a regular painful task of getting under that tank, moving a dozen hoses out of the way, dropping a big flange in order to clean the outlet screen...

Gonna have to wait until Monday to hear whether they think it's not going to work in a tank full of ATF, but at a minimum, I think I'd need two others right away for fuel tanks.

--Dave

 

[Delmer]

I'm hearing from various persons, whom I suspect of knowing what they're talking about, that this is a widespread problem. Wouldn't a simple remedy be to provide a form of controlled expansion/contraction to the hyd tank, eg a bladder installed at a high point? With that, there'd at least seem to be no possible net /increase/ in the trapped moisture left behind, after each occasion when the tank is opened to atmosphere. Tank would still be allowed to release pressure at something close to "do it or bulge forever" pr - just not take in any air.

In my case, since the intake is very low and not filtered (only 'screened,' we think) it looks to me as if I can't afford to be much less than purist about this, or I will be pulling rusty grit into my pump - hope I haven't already been doing a lot of that.

--Dave

The expansion bladder idea is sound. I can't remember where I've seen it, maybe not in this field even, any Harvestores in Hawaii?. An expansion bladder inline with the dessicant filter would be the ultimate protection. The only new moisture would be if the hydraulic system leaked and needed to suck new air in, or if the cap was opened.

 

[lantraxco]

http://hydraulicspneumatics.com/hyd...reather-incorporates-check-valves-longer-life

http://www.machinerylubrication.com/Read/346/desiccant-breathers

https://www.google.com/search?q=hyd...&ved=0CIYBELMYahUKEwjRibq3mL7HAhXJ04AKHQEMAYE

https://www.hyprofiltration.com/products/detail/reservoir-accessories/hy-dry-desiccant-breather/

http://www.filtroil.com/desiccant.shtml

http://www.lelubricants.com/desiccant-breathers.html

 

[Pants]

Lantraxco - thanks for the intro & survey of desiccant breathers...interesting reading. Come business hours, I think I need to talk to someone at Hy-Pro to ask about specific apps. Their page at https://www.hyprofiltration.com/products/detail/reservoir-accessories/hy-dry-desiccant-breather/ links to a pdf that seems like it's the best engineered for my concerns: they talk about it being fitted with inlet/outlet "check-valves" (might better be described as "regulators?") that are intended to avoid needless 'breathing' through the consumable desiccant, so as to prolong its lifespan, by not opening until some low pressure threshold is reached.

I'm envisioning I might either modify the current radiator-cap-style cover to accept a standard MPT on a replaceable breather, but may not have room...not a big problem to mount it /somewhere/, though.

Some breathers seem to be specified in terms of CFM, which I find slightly puzzling. I guess some reservoirs, eg factory settings, must see big regular changes in volume of tank fluid (single-acting cylinders, aux circuits, or other places where fluid "goes out" without returning approximately simultaneously?), but my mental picture is that this isn't so much the case with an excavator, loader, etc - true?

Now that I think about it, a couple of years back I saw someone's DIY version of something like this, maybe for a fuel storage tank, where he revealed the 'secrets': that the desiccant could be baked dry (returning to original color) and then re-used, and was commonly available as a color-indicating kitty litter of some variety at your (not mine, though) local WalMart...I think he had it installed in some clear tubing where it was easy to check for color on a regular basis.

Or even simpler - maybe I just need to fill my hyd tank with kitty-litter, and be done with it for the next few years?

--Dave

 

[lantraxco]

Any hydraulic system with cylinders will constantly change the oil volume in the reservoir, this is why in most owner manuals the manufacturer will specify a certain boom/stick/bucket configuration for checking hyd oil level. Most of the machines I dealt with it was bucket rolled inward to stop, stick pulled in to stop, boom down until the back of the bucket or bucket linkage rested on the ground. Sort of a set point for the oil level.

Breather systems fall into three categories:

1) Those with a simple breather which usually has a screen or air filter in it but air moves freely in and out.

2) Those with a breather with check valves, when the oil level lowers in the tank a low pressure check opens and allows (usually filtered) air in to fill the space in the tank, when the oil level rises a higher pressure check valve allows the air to compress up to it's opening pressure, will usually be 8-10 pounds or sometimes higher, machines like yours with the radiator cap are usually marked .7 or 1, which is either bar or Kgm/Cm2, roughly 14 psi=1 of either for this purpose.

3) Some machines actually have an air compressor which pressurizes the air space in the hydraulic tank, the air is usually run through at least a water separator first which helps on humidity. The constant pressure actually serves to supercharge the piston pumps which makes them very happy indeed.

Now you know more than you ever wanted to about mobile hydraulic breather systems, LOL!

 

[Nige]

Don, The 307 belonging to the OP is kinda like your option 3 with a sealed tank but instead of an external air compressor it's only the added pressure created by the hot air above the oil that pressurizes the suction line somewhat, a bit like a track-type tractor hydraulic tank. I'm leaning to the idea that at least it should have the (radiator-style) pressure cap replaced plus all the seals for the oil filter housing as a first step to try to get it airtight.

 

[lantraxco]

Nige, I think you're right on the procedure. As I recall the tube coming off the pressure cap just went into never land, there's no filter on the end of it?

Plumbing in a spin on return filter somewhere with a water trapping media might be something to consider also, pull some of the entrained water out of the hydraulic oil? Zinga AquaZorb comes to mind.

 

[Pants]

Any hydraulic system with cylinders will constantly change the oil volume in the reservoir, this is why in most owner manuals the manufacturer will specify a certain boom/stick/bucket configuration for checking hyd oil level. Most of the machines I dealt with it was bucket rolled inward to stop, stick pulled in to stop, boom down until the back of the bucket or bucket linkage rested on the ground. Sort of a set point for the oil level.
...

I was thinking of the chalkboard line-drawing of a cylinder, where the rod exists only as a line, I suppose. In that world, double-acting cylinders wouldn't draw from or add to any fluid from/to their reservoirs as they move...whatever qty of fluid is being pushed in on the high pressure side of the piston would be returning from the low-pressure side of the piston...but that neglects the volume of fluid that's displaced by the rod - so the extension of any rod out of its cylinder requires more fluid volume to make a given piston motion, vs retraction.

The machine position you described sounds like it'd be the theoretical lowest-reservoir condition, wherein as much rod is extended as possible.

(What? I'm late to the party?)

--Dave

 

[Nige]

Most excavators have a diagram showing where to put the equipment before checking the tank level. I am not 100% sure if it's the same for the Op's 307 but this is the diagram that applies to all the Cat excavators I've ever been around. The US-built 307 calls for this method to be used, I don't see why a Japanese-built machine would be any different.

 

[Pants]

Nige, I think you're right on the procedure. As I recall the tube coming off the pressure cap just went into never land, there's no filter on the end of it?

Yes, that's exactly the setup - though I confess I didn't yet go through the gymnastics required to find the open end of the 1/4" tubing coming off the bottom of the cap-fitting on the tank to confirm it just goes to daylight somewhere.

Plumbing in a spin on return filter somewhere with a water trapping media might be something to consider also, pull some of the entrained water out of the hydraulic oil? Zinga AquaZorb comes to mind.

I checked those out just now - can't tell, are they intended to process the fluid directly, or the reservoir air?

--Dave

 

[Nige]

Plumbing in a spin on return filter somewhere with a water trapping media might be something to consider also, pull some of the entrained water out of the hydraulic oil? Zinga AquaZorb comes to mind.

Pants, what he's talking about is to install a new full-flow filter into the return line to the hydraulic tank that not only filters the oil but also has the capacity to remove any trapped water from the oil as it passes through the element.

 

[Pants]

I'd consider the fluid-contact type, but from my brief survey of desiccant breathers it seems they offer a key advantage of "at-a-glance" assessment of their moisture saturation level, eg 'change it when it's dark green' (or whatever). Are any of the inline fluid-handling types known to offer some kind of visual condition assessment?

--Dave

 

[lantraxco]

Yes, full flow, or if there's a suitable circuit a "kidney loop" filter to extract water from the oil that passes through the filter. The absorbent media in these filters will shut flow off when they saturate so the normal restriction gauge or indicator on the filter will let you know it's full and bypassing, same as if it had filled up with dirt.

You still need something on the breather end to keep the tank from rusting up so much, but the oil filter would help the oil live longer and with it hopefully all the hydraulic components as well. May or may not be worth the money, time, and hassle. The full size head takes both short and long filters, if you have room the long filter will obviously go longer between changes.

As an aside, I first used these Aquazorb filters on diesel fuel pumps, we had a couple bad batches of fuel from our supplier at one point and even though fuel was cheap then, fuel filters were not, and throwing cases per week of the Deere rectangular glass filters away added up quick. There were some associated costs related to injection pumps and injectors as well, filters aren't perfect after all. When installed on our in ground tank pump and all our transfer tanks in pickups and our lube truck, the Aquazorb filters would literally choke fuel flow down to a small trickle when they saturated with water. Slap another one on and happily keep pumping.

 

[lantraxco]

Most excavators have a diagram showing where to put the equipment before checking the tank level. I am not 100% sure if it's the same for the Op's 307 but this is the diagram that applies to all the Cat excavators I've ever been around. The US-built 307 calls for this method to be used, I don't see why a Japanese-built machine would be any different.

View attachment 139549

That actually makes more sense to me, as it looks like all the cylinders are about mid stroke? We had Mitsubishi and Hitachi hoes back when I worked on them, if I'm remembering correctly they all called for the tucked in, laid down configuration.

 

[Nige]

The Cat recommendation for equipment position while checking the tank level is also a very logical place to leave the machine when parking it overnight IMHO.

 

[Pants]

The Cat recommendation for equipment position while checking the tank level is also a very logical place to leave the machine when parking it overnight IMHO.

From what I see on jobsites here, a common practice is to extend boom and stick as far as possible to close off entrances against thieves, and/or to lay them down on hoe-rams or spare buckets for the same reason...Always wondered who would want to steal something like a bucket or hoe-ram that wouldn't also know that the machines all keyed alike anyway.

 

[Pants]

Yes, full flow, or if there's a suitable circuit a "kidney loop" filter to extract water from the oil that passes through the filter. The absorbent media in these filters will shut flow off when they saturate so the normal restriction gauge or indicator on the filter will let you know it's full and bypassing, same as if it had filled up with dirt.

You still need something on the breather end to keep the tank from rusting up so much, but the oil filter would help the oil live longer and with it hopefully all the hydraulic components as well. May or may not be worth the money, time, and hassle. The full size head takes both short and long filters, if you have room the long filter will obviously go longer between changes.

As an aside, I first used these Aquazorb filters on diesel fuel pumps, we had a couple bad batches of fuel from our supplier at one point and even though fuel was cheap then, fuel filters were not, and throwing cases per week of the Deere rectangular glass filters away added up quick. There were some associated costs related to injection pumps and injectors as well, filters aren't perfect after all. When installed on our in ground tank pump and all our transfer tanks in pickups and our lube truck, the Aquazorb filters would literally choke fuel flow down to a small trickle when they saturated with water. Slap another one on and happily keep pumping.

Sounds like a good recommendation, if I can afford it (/both/ a breather setup, and a fluid-handling desiccant setup). Would the kidney-loop require something new (eg a pump) to move the fluid through it, or can it scavenge from existing fluid movement? I'm thinking of how toilet-paper filters just steal a small amount of 'excess' pressure at engine oil-pump outlet, to create a low-flow bypass loop. Maybe I could be looking for a place to tap a smallish bypass in on the high side of my pump, then, regulated with...I dunno, a needle-valve?

--Dave

 

[lantraxco]

I'm not familiar with the 307 so I don't know about it's circuits. Some machines have circuits where smaller pumps will be circulating oil, so you can use a smaller filter and the oil all eventually gets filtered over time. That machine is small enough you can probably just plumb right into the return to tank as Nige says, though if you left the OEM filter in the circuit also you would see some increase in back pressure on the return line possibly.

 

[bigbob]

Most excavators have a diagram showing where to put the equipment before checking the tank level. I am not 100% sure if it's the same for the Op's 307 but this is the diagram that applies to all the Cat excavators I've ever been around. The US-built 307 calls for this method to be used, I don't see why a Japanese-built machine would be any different.

View attachment 139549

Niege, I believe all US market 307 s were built in Japan. I had a 1994 2PM I recently sold. It was built in Japan. The picture you showed was the way to configure the boom/stick/bucket to check the hydraulic oil level. I traded the 307 for a 308E 2, which was one of the last US market machines to be built in Japan. They are now built in Georgia. The 307 is no longer available in the US market, but is still built for other markets.