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M916-M920 Tech & Tips

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Sedona Az.
Its always refreshing to see the helpful people on this site helping one and other out.
Thank you Soni for the thread and all your input and good advice.
 

M920

Member
892
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18
Location
chama/nm
One more before you drive you rig check that the oil pump for the drop box was not like mine. The can be installed 90* out and you will blow bubbles and not curculate the oil. The pump looks to be square but with what I will call a tab on one side and if you look from the back side the tab should be pointing down.


This is good advice and I would like to add two more things to the above tips:

(1) this first one is obviously not an issue for you in Florida...lol, but the oil pump can be disconnected from the drive, for extreme cold weather operation. There is a 1/2" thick steel spacer, that's held on by the same 4 bolts that hold the pump on to the top rear of the TC.
If the spacer is installed between the pump and the TC, the pump is disconnected for extreme cold weather operation! (-10F and below)
If the spacer is installed on the back of the pump just beneath the bolt heads, and the pump is bolted directly to the back of the TC housing, it is engaged and in the normal operating position.
This should certainly be checked when picking up one of these trucks, and before taking them on an extended road trip in hot weather!

Just from my experience; I found that it is not really necessary to disengage the pump drive for extreme cold weather operation, (I'm afraid I would forget to re-engage it, once it warms up again...lol) if you take it easy on the speed, when starting out.
I do live in an area that gets -20F and below temperatures every winter.
So just to be safe, I drive the truck nice and slow for the first mile or two to make sure the oil in the TC thins a little, before getting it on up to highway speeds....

I did have a twisted off pump input shaft, the first year I owned the truck, but I'm not sure, what the exact cause of that failure was.


(2) the front extension on the TC, that houses the air disconnect for the front drive shaft, has its own drain plug. It does not hold much oil but if you want to drain all the oil you need to take that one out to. To make sure that this area gets filled again when adding new oil, you can take the little oil level plug out and make sure you get oil through that one to.
Also....the TC does not hold as much oil as one would think it should, so on my trucks, I drain it, I clean the above mentioned mesh filter in the bottom T-fitting and I change the oil in it about every 5000 miles.

A little foot note:
When I first drove my "new" M916 for a couple of miles at highway speeds, the TC got really hot to the touch....So of course I feared the worst, having not checked all the fluid levels yet. I pulled the oil level plug out, anticipating a low oil level.....instead I was drenched, by what appeared to be about two gallons of extra gear oil!!!
I guess someone wanted to make sure, that the TC had good lubrication and must have filled it to the brim with oil!!!!..... trough the vent plug i guess.....aua

Soni
 
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eldgenb

Member
748
1
16
Location
Spokane WA
A little foot note:
When I first drove my "new" M916 for a couple of miles at highway speeds, the TC got really hot to the touch....So of course I feared the worst, having not checked all the fluid levels yet. I pulled the oil level plug out, anticipating a low oil level.....instead I was drenched, by what appeared to be about two gallons of extra gear oil!!!
I guess someone wanted to make sure, that the TC had good lubrication and must have filled it to the brim with oil!!!!..... trough the vent plug i guess.....aua

Soni
Jar Heads..... Army Mechanics are just as dumb, I know because I was one![thumbzup]
 

M920

Member
892
24
18
Location
chama/nm
Jar Heads..... Army Mechanics are just as dumb, I know because I was one![thumbzup]
Ok Eldgen, you're being funny now!....That's not in any way what I was trying to say! lol..... first of all I would NEVER generalize on issues like that and second of all, if there where indeed a few "bad apples" out there.... YOU ARE CERTAINLY NOT IN THAT CATEGORY!!!!!!
I have been following your thread on your M920 conversion with awe, and really admire the quallity of your work! I can't wait to hopefully meet you in the future and see that cool truck of yours in person! Aah...Road Trip.... Yes!!!:driver:

Oh and Btw....this M916 of mine, according to the maintenance records I found in the cab, was actually serviced by the Maintenance Division of Northrop Grumman, not the Marines or the Army!:roll:

Soni
 

M920

Member
892
24
18
Location
chama/nm
Soni thanks for the drawing of what has to be worked on the drum. I have a friend that is getting ready to do his and it will be helpfull to him. You seem like a real nice guy but you don't have to call me DEER.
You are very welcome James.....I certainly did not mean to insult you by calling you "DEER" I meant to say "ELK" of course! lol :jumpin:

Soni
 

Bighurt

New member
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Location
Minot, ND
Alright seeing as though I have no way of looking at these trucks, and I don't have the manual.

Can someone answer a question for me?

Is the winch and hydraulic system contained in the same unit on the back of the truck? If I remove the unit from the frame do I lose the trucks hydraulic system?

Or...

I'm just throwing this out there in case the above is true... Is the hydraulic system able to be removed from the housing and re-located? Divorced from the winch so to say...

The reason I ask, the project I'm toying with utilizes linear actuators (12 volt) to raise the RV roof. However there is significant issues with getting equal pressure from the actuators to raise the unit equally from all 4 corners. one of the reason Unicat has the market cornered.

It's been suggested that hydraulics would self equalize and give a uniform lift. It's also been suggested to utilize circumferential chains to direct drive them together. This would make for difficult interior.

My thinking is that by retaining the trucks Hydraulic system it maybe possible to use it for the lift portion. in addition it will also make it possible to have front and rear hydraulic winches as well as a hydraulic level up system.

Wheels turning...just need a road map.

Anything on the hydraulic system would help?
 

oldMan99

Member
479
12
18
Location
Polk County, Florida
Alright seeing as though I have no way of looking at these trucks, and I don't have the manual.
You do now! Check your email... :)

Can someone answer a question for me?

Is the winch and hydraulic system contained in the same unit on the back of the truck? If I remove the unit from the frame do I lose the trucks hydraulic system?

I'm just throwing this out there in case the above is true... Is the hydraulic system able to be removed from the housing and re-located? Divorced from the winch so to say...
Unless I am seriously mistaken.... The hydraulic pump is located on the transmission. The manuals you now have will tell you how to activate the pump.

You can remove the winch and winch controls and still maintain the pump. I'm not positive on the exact way that is all built and if the tank comes off with it or not but If my memory is correct it is mounted to the same pedestal as the winch but it is probably removable from said pedestal for reinstalling someplace else. You will need some sort of fluid tank, the size of which will depend on what your using the system for. The stock system is something like 30 or 40 gallons if I member correctly from the manual.

The reason I ask, the project I'm toying with utilizes linear actuators (12 volt) to raise the RV roof. However there is significant issues with getting equal pressure from the actuators to raise the unit equally from all 4 corners. one of the reason Unicat has the market cornered.

It's been suggested that hydraulics would self equalize and give a uniform lift. It's also been suggested to utilize circumferential chains to direct drive them together. This would make for difficult interior.
If this were your only use of hydraulics on the truck I would suggest taking the PTO pump off and using an electric pump like on a lift gate. Reason I say this is obviously for the PTO pump to work the engine must be running. Also, the manual says that before you operate the winch, you need to run the pump for 30 minutes to warm it up. I'm not sure you would have to do that just to raise your roof though. With the electric pump you could move your roof whenever you wanted to without the engine needing to be running.

My thinking is that by retaining the trucks Hydraulic system it maybe possible to use it for the lift portion. in addition it will also make it possible to have front and rear hydraulic winches as well as a hydraulic level up system.

Wheels turning...just need a road map.

Anything on the hydraulic system would help?
You do know how much large hydraulic winches weigh right?? LOL.. I'm most likely going to use them front and rear but they are impressively heavy. Anyway, if your going to be mounting hyd winches then yeah, keep the PTO pump. Just be aware they do not work like electric winches do where you winch and drive the vehicle out of your stuck, you use only the winch. On the M920 the manual says to engage the PTO with the transmission on 1st gear and then shift into neutral and idle up to operational speed. So you can drive and winch. Meaning you need a winch large enough to do the job solo.

For the hydraulic leveling I am considering using a 36" stroke cylinder at each corner of the box mounting it on some kind of pivoting bracket so that when driving you swing them up even with the bottom of the camper box and when camping you swing them down sort of like a table leg on a folding card table. It will take about 10' of stroke just to reach the ground but you still have 26" stroke left. With luck you might be able to design it so that you could use the system to change flat tires. They do make units for conventional RV's but I am thinking the MV RV will be way to tall to sue any of them w/o compromising ground clearance. I am also considering looking for some used "Outrigger" legs like on a power company truck. Those would sure level and pick up the entire truck for tire changing. And depending on your point of view, either look cool or stupid...lol.

Does this help any?
 
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Bighurt

New member
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Location
Minot, ND
Does this help any?
Of course.

I did assume the truck needed to be running to engage the pump I just didn't know it would be so long. I sorta envision pulling up level the truck run up the roof and shut her down for the night.

Thanks for manuals I read them when i get a chance, at the minimum flip through a drool a little.

I am familiar although only slightly with Hydraulic winches, yes I'm aware of the weigh but this is a 20 ton truck. I'm hoping the box weighs in less than 3 tons loaded... But there aren't a lot of choices when it comes to a winch capable of getting a M920 unstuck. Might as well use Hydraulic since the truck is already equipped.

In either case there will be room to spare.

I like the outrigger idea may not work for my concept but that doesn't mean it won't for yours.

Back to the roof hydraulics, nothing is to say these can't be run offf a 12 volt pump using the same reservoir. Again assuming I keep the hydraulics.

I bet the manual has the hydraulic system working pressure...that was my last question...for now.

Thanks
 

oldMan99

Member
479
12
18
Location
Polk County, Florida
Of course.
I am familiar although only slightly with Hydraulic winches, yes I'm aware of the weigh but this is a 20 ton truck. I'm hoping the box weighs in less than 3 tons loaded... But there aren't a lot of choices when it comes to a winch capable of getting a M920 unstuck. Might as well use Hydraulic since the truck is already equipped.
According to the book: Curb weight M920 = 30,270lbs. (15 tons) But, yeah, always better to be high than low when calculating such things. This is why I am contemplating using the 45k winch on the back, (And MAYBE one on the front as well) because I'll have at least another 20k lbs on top of the truck for a GVW of about 50k lbs. Get that stuck and a Warn 8k just might not be quite enough....


In either case there will be room to spare.

I like the outrigger idea may not work for my concept but that doesn't mean it won't for yours.
LOL it might not even work for my concept but it is at least worth investigating!

Back to the roof hydraulics, nothing is to say these can't be run offf a 12 volt pump using the same reservoir. Again assuming I keep the hydraulics.
Your right, you could use the same reservoir, all you would have to do is "T" into the suction and return line at the port, (Or install a second set of ports in the tank) and run the lines to your electric pump. In fact, that is probably a good way to do it.

As a side note, sort of like your elevating roof.... I was considering using hyd to raise a shade cover (roof) over my roof top observation platform. That way I could make a "Lid" for the platform and raise it with the hyd. Problem with that is I would need 4 cylinders with a 7 to 8' stroke. I have yet to find anything even close to that long but I bet they will be over a grand each when/if I ever do find them, and at that price, I'll have to come up with "Plan B" to provide shade on the observation deck...

I bet the manual has the hydraulic system working pressure...that was my last question...for now.

Thanks
TM 9-2320-273-20Section XXVII
WINCH2-79. INTRODUCTION.

The winch is installed on M916 and M920. The assembly is located behind the cab with all operatingcontrols.2-80.

WINCH.

1.INLINE RETURN FILTER. Throwaway filter removes water and dirt from oil returningto reservoir.

2.WINCH CABLE. 7/8 inch (22.2 mm) diameter wire rope, 150 feet (46 m) long. Rated at75,000 Ibs (33,600 N) minimum breaking strength.

3.CONTROL VALVE. Detented “up” position supplies pressure to outlet for auxiliaryhydraulic system. Down position provides high speed winch operation.

4.AUXILIARY THROTTLE. Adjusts power input to PTO by altering engine speed.

5.DIRECTIONAL CONTROL VALVE. Controls winch direction. Spring-loaded valve returnsto middle position when released, causing winch brakes to apply.

6.HYDRAULIC MOTOR. Turns winch to pay out or haul in cable. Powered by oil underpressure from pump.

7.DUAL PUMP. 22 gpm/gear; total of 44 gpm @ 2200 engine rpm gear type pump poweredby PTO supplies 2350 psi (14,800 kPa) hydraulic pressure to motor through hydraulicvalves.

8.POWER TAKEOFF. Drives dual pump. (See paragraph 2-78 for functional description.)

9.INLET STRAINER. Removes large particles from oil going to dual pump.

10.HYDRAULIC RESERVOIR. Supplies oil to dual pump and receives oil returning fromsystem.

11.COVE R PLATE. When removed allows access to interior of reservoir to service interalstrainer and for general clean out.

That should cover the question.... LOL
 
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eldgenb

Member
748
1
16
Location
Spokane WA
just some general clarification on your questions. The reservoir needs to be big enough to have a 1 minute run time capacity, so in the case of the 920 it is a parallel pump producing a total of 44 gmp which is why the reservoir is 50 gallons with 44 gallon full mark. I agree that you should get an electric pump for raising or lowering the roof, reason why is they supply maybe 1.5 gpm and if you tried to use the 920 pump even if you just use one side of it raising and lowering something that small in dimension would be more like a space shuttle takeoff. You can try to restrict the flow down but it would cost you tons more trying to do that then to buy an electric pump.
As for re using the winch. It is heavy, huge, and requires every bit of that 44 gpm to move at any speed. The 5 ton m816 has a similar weight rating as the 920 weighing in at over 32k and they have a standard 5 ton 20k winch on that truck and it works just fine, convert this to hydraulic and reduce the pump to a mono pump for a total of 22 gpm and be done with it. Something tells me that you will not be burying this truck to its nuts in mud so it should be more than adequate especially if you are removing the winch, 5th wheel plate, tag axle etc.
 

oldMan99

Member
479
12
18
Location
Polk County, Florida
I know I did not make the original post/question about the hyd system but your answer give me more info that I could possibly get from reading the book and it leads me to a couple new questions. Both the OP and myself are working on very similar projects with very similar designs in mind so my questions here will likely help/apply to him as well.

just some general clarification on your questions. The reservoir needs to be big enough to have a 1 minute run time capacity, so in the case of the 920 it is a parallel pump producing a total of 44 gmp which is why the reservoir is 50 gallons with 44 gallon full mark.
I have worked on hyd systems in helicopters but this is pretty different. A "Parallel pump" is that basically 2 individual pumps in one housing? Am I correct in understanding that you can shut off/disable one of the circuits? If so, how do you go about doing this?

I agree that you should get an electric pump for raising or lowering the roof, reason why is they supply maybe 1.5 gpm and if you tried to use the 920 pump even if you just use one side of it raising and lowering something that small in dimension would be more like a space shuttle takeoff.
I almost blew coffee all over my keyboard with that one.... lol. (Might be fun to watch...once..)

You can try to restrict the flow down but it would cost you tons more trying to do that then to buy an electric pump.
Forgive my hyd design ignorance but... Can't you just flow restrict the line by using a smaller diameter fitting/hose or a control valve that is designed for a lower flow?

As for re using the winch. It is heavy, huge, and requires every bit of that 44 gpm to move at any speed. The 5 ton m816 has a similar weight rating as the 920 weighing in at over 32k and they have a standard 5 ton 20k winch on that truck and it works just fine, convert this to hydraulic and reduce the pump to a mono pump for a total of 22 gpm and be done with it.
The Ramsey 45k hyd winch (#RPH 45,000) which looks to be about the same general physical size of the 45k winch on the 920 weighs in at a back breaking 689 pounds.

The Ramsey 20k weighs 375lbs and the 30k 486 lbs. They both use 15gpm, I could not find the PSI requirements for the Ramsey winches.

From what I have been able to learn most modern winches need 3,000psi. The pump on the M920 "Only" puts out 2,350 psi.

The Warn company offers both a "Standard" pressure and a low pressure version of their winches. They also offer a short or long drum, the difference being how much cable you can keep on the drum. Since we are talking large vehicles and my personal presence is for as much cable as I can get, weights will be for the long drum version. See below:

Rating Weight PSI GPM
20k 329 3,000 20
20k low press. 322 2,200 20

30k 361 3,000 20
30k low press. 361 2,320 20

I would be interested in the weight of the 20k hyd winched used on the MV's if anybody happens to have it, also the PSI and flow output of the pump used to drive it.

Something tells me that you will not be burying this truck to its nuts in mud so it should be more than adequate especially if you are removing the winch, 5th wheel plate, tag axle etc.
Now, given all the above; The M920 basic weighs in at 30k. I'm not sure how much weight the OP is planning on by my 920 will be hauling around another 20-25k of RV on it's back for a total of about 50-55k pounds.

I can't speak for the OP but in talking to him I believe he probably understands the concept of, "When your stuck, stop digging in and start winching" so that your comment about not burying the truck is likely correct. I know I learned that lesson many years ago. I have a winch for a reason... to be used, not to look pretty. Unlike some people, I find no embarrassment in using it to make my life much easier. When stuck the sooner you turn to the winch, the easer the process will go.... usually....lol. Of course right here on SS we recently had a member that went from driving to front bumper on the ground instantly and without any warning. When that happens, you better be ready with enough winch power to haul your dinosaur out.

Even with a snatch block the 20k is only going to give you 40k of pull. That might not be enough for a truck looking at the better part of 50k static weight. Even a 30k with a block will just barely give me = the weight of the rig. And that does not include drag/suction of whatever it is stuck in.

I'm thinking that for both the OP and myself, a 30k is probably going to be the minimum. Of course if either of us finds a 20 MV winch for the right price it might find it's way onto the front of our respective RV's. I know I'll be relocating my 45k to the back of the rig.
 

Excuse Me

New member
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Location
Hillsboro Oregon
In general, a tandem hydraulic pump will be two seperate pumps coupled together, having two seperate outlets for individual circuits, and two seperate inlets, but occasionally a tandem pump system will share a common inlet.
Gear pumps are a positive displacement pump with a fixed displacement capacity. That means for each revolution of the input shaft of the pump, a specific amount of fluid will be delivered to the outlet.

So, using a fixed displacement pump and restricting the flow with hose size or coupling size, will cause the safety relief valve to have to carry the remainder of the flow at full pressure. This will heat the fluid rapidly and make noise while doing so as well as consume near the same hp as if you were using the pump at full work load. Not really a good idea.

You can reduce the flow using a flow control valve within the plumbing of the open center, fixed displacement system. This way, what ever small amount of fluid you need can be split off to the work circuit, and the remainder of the fluid simply returns to the reservoir unworked.

The duty cycle needs to be considered when sizing the reservoir. The 44 gallon size and the 44 gallon displacement, means that when the system was designed, it was designed to have the ability to pump full flow, at full pressure, constantly or 100% of the time the pump is turning. Since it is unlikely that many will be using it to that extent, a smaller reservoir can be used if need be.

Using fluid to raise a camper top might be cool, but very expensive and inefficient. If one corner has just 10 pounds more weight than the other three, in a open loop plumbing, the fluid will travel to the point of least resistance, causing a bind, and at the power level most hydraulics have, likely a broken camper top. AC/DC powered Linear actuators can be timed with settable limits that can be repeated. Running small wires is much easier and cheaper to do than expensive and heavy hydraulic lines.

For using hydraulics on the outriggers, you bet. A short stroke cylinder can easily achieve long stoke work with the use of linkages. This is done a lot on construction equipment and agricultural equipment. Take a look at the bucket curl on an excavator. or the wing fold on a farm implement. There are as many ways to accomplish this as there are people that wish to give it a try. If you really wanted to have a cool outrigger system, find a leveling system from a 4 way leveling hillside combine at a part out yard and integrate it into your outrigger controls. This way you do not have to watch a bubble glass as you move each corner up or down, you simply hit a switch, and the camper will level all by itself. You tube has several videos of hillside combines working.

IMO.
 

eldgenb

Member
748
1
16
Location
Spokane WA
I know I did not make the original post/question about the hyd system but your answer give me more info that I could possibly get from reading the book and it leads me to a couple new questions. Both the OP and myself are working on very similar projects with very similar designs in mind so my questions here will likely help/apply to him as well.


I have worked on hyd systems in helicopters but this is pretty different. A "Parallel pump" is that basically 2 individual pumps in one housing? Am I correct in understanding that you can shut off/disable one of the circuits? If so, how do you go about doing this?
Yes that is correct it is two identical pumps joined together by a removable splined shaft. You can take the pump apart and remove the rear pump and put it back together. The gaskets are reusable, you will need to buy 8 shorter hex bolts and locktite everything back together, takes about 15 minutes, super easy.


I almost blew coffee all over my keyboard with that one.... lol. (Might be fun to watch...once..)
Yeah, that was the first vision that came to mind when I saw the question.


Forgive my hyd design ignorance but... Can't you just flow restrict the line by using a smaller diameter fitting/hose or a control valve that is designed for a lower flow?
As mentioned above they make valving that diverts the excess pressure back to the tank.


The Ramsey 45k hyd winch (#RPH 45,000) which looks to be about the same general physical size of the 45k winch on the 920 weighs in at a back breaking 689 pounds.

The Ramsey 20k weighs 375lbs and the 30k 486 lbs. They both use 15gpm, I could not find the PSI requirements for the Ramsey winches.

From what I have been able to learn most modern winches need 3,000psi. The pump on the M920 "Only" puts out 2,350 psi.

The Warn company offers both a "Standard" pressure and a low pressure version of their winches. They also offer a short or long drum, the difference being how much cable you can keep on the drum. Since we are talking large vehicles and my personal presence is for as much cable as I can get, weights will be for the long drum version. See below:

Rating Weight PSI GPM
20k 329 3,000 20
20k low press. 322 2,200 20

30k 361 3,000 20
30k low press. 361 2,320 20

I would be interested in the weight of the 20k hyd winched used on the MV's if anybody happens to have it, also the PSI and flow output of the pump used to drive it.



Now, given all the above; The M920 basic weighs in at 30k. I'm not sure how much weight the OP is planning on by my 920 will be hauling around another 20-25k of RV on it's back for a total of about 50-55k pounds.

I can't speak for the OP but in talking to him I believe he probably understands the concept of, "When your stuck, stop digging in and start winching" so that your comment about not burying the truck is likely correct. I know I learned that lesson many years ago. I have a winch for a reason... to be used, not to look pretty. Unlike some people, I find no embarrassment in using it to make my life much easier. When stuck the sooner you turn to the winch, the easer the process will go.... usually....lol. Of course right here on SS we recently had a member that went from driving to front bumper on the ground instantly and without any warning. When that happens, you better be ready with enough winch power to haul your dinosaur out.

Even with a snatch block the 20k is only going to give you 40k of pull. That might not be enough for a truck looking at the better part of 50k static weight. Even a 30k with a block will just barely give me = the weight of the rig. And that does not include drag/suction of whatever it is stuck in.

I'm thinking that for both the OP and myself, a 30k is probably going to be the minimum. Of course if either of us finds a 20 MV winch for the right price it might find it's way onto the front of our respective RV's. I know I'll be relocating my 45k to the back of the rig.
I would agree with your statement for a rear winch, if it ever gets that bad you are not going to want to go forward anyways. The 20k winch never came hydraulic just pto, you can put a hydraulic motor on it and convert it. The 20k is also conservatively rated like everything else the military puts out. I would save the big bucks for a trick between the rails rear winch and make that your biggie.
 

oldMan99

Member
479
12
18
Location
Polk County, Florida
In general, a tandem hydraulic pump will be two seperate pumps coupled together, having two seperate outlets for individual circuits, and two seperate inlets, but occasionally a tandem pump system will share a common inlet.
Gear pumps are a positive displacement pump with a fixed displacement capacity. That means for each revolution of the input shaft of the pump, a specific amount of fluid will be delivered to the outlet.

So, using a fixed displacement pump and restricting the flow with hose size or coupling size, will cause the safety relief valve to have to carry the remainder of the flow at full pressure. This will heat the fluid rapidly and make noise while doing so as well as consume near the same hp as if you were using the pump at full work load. Not really a good idea.

You can reduce the flow using a flow control valve within the plumbing of the open center, fixed displacement system. This way, what ever small amount of fluid you need can be split off to the work circuit, and the remainder of the fluid simply returns to the reservoir unworked.
OK, if I understand this correctly, the M920 is a fixed displacement system. Is this because the winch does not actually “use” fluid, (meaning like a ram would “use” or temporarily store fluid to extend the ram and then return it to the system when the ram retracts). (More about ram usage below) If you wanted to run both a stock 45k winch that needs the full 44gpm and (not at the same time, but on the same vehicle) a 30k winch that uses 20gmp what do you need to do to make the lower flow tool work properly?

The duty cycle needs to be considered when sizing the reservoir. The 44 gallon size and the 44 gallon displacement, means that when the system was designed, it was designed to have the ability to pump full flow, at full pressure, constantly or 100% of the time the pump is turning. Since it is unlikely that many will be using it to that extent, a smaller reservoir can be used if need be.
I assume this changes some if your using rams (like to level the vehicle) because the rams “Keep” some of the fluid. Of course (I assume here) that if your using the rams, your not using the winch at the same time so the loss of fluid would not matter because by the time you winch the rams will have given their fluid back and the reservoir is plenty large enough to fill my 4 cylinders and then some… Correct?

Can you move 1 ram at a time SLOWLY or will it slam into the ground? Do these control valves work proportionately like on an excavator or are they all or noting?

Using fluid to raise a camper top might be cool, but very expensive and inefficient. If one corner has just 10 pounds more weight than the other three, in a open loop plumbing, the fluid will travel to the point of least resistance, causing a bind, and at the power level most hydraulics have, likely a broken camper top. AC/DC powered Linear actuators can be timed with settable limits that can be repeated. Running small wires is much easier and cheaper to do than expensive and heavy hydraulic lines.
I am thinking about building my (sleeping) bed sideways across the front of the box and using some kind of motors to raise it up to the roof leaving the dining area below. I would be interested in discussing the linear actuators (possibly in another thread so we do not hi-jack this one away from things relayed to the truck itself) to learn more about them. That same conversation would likely help with the roof question as well.

For using hydraulics on the outriggers, you bet. A short stroke cylinder can easily achieve long stoke work with the use of linkages. This is done a lot on construction equipment and agricultural equipment. Take a look at the bucket curl on an excavator. or the wing fold on a farm implement. There are as many ways to accomplish this as there are people that wish to give it a try.
I was thinking of either a simple straight ram with a foot/base that would (manually) swivel up when not in use like the smaller trailer tongue jacks, OR finding real outrigger legs from a utility truck/crane/big wrecker and fitting them to the truck. I understand the linkages your talking about but that seems intensive in design and implementation.

If you really wanted to have a cool outrigger system, find a leveling system from a 4 way leveling hillside combine at a part out yard and integrate it into your outrigger controls. This way you do not have to watch a bubble glass as you move each corner up or down, you simply hit a switch, and the camper will level all by itself. You tube has several videos of hillside combines working.

IMO.
I searched youtube and easily found several videos of that. Most only show the combine moving along the hill already “Adjusted”. After 4 or 5 I found one that shows a combine adjusted and then make a u-turn on the hill and go back, all the while keeping the cab level. That was actually pretty cool. I am guessing in addition to the controller you would need some electric/hydraulic control valves and that even used parts can’t be inexpensive. But it would be a cool system. I know they make auto leveling jack systems for RV’s, it may be possible to get the necessary electrical components and use them to run our larger jacks once they have been pivoted into the vertical position. For those interested: YouTube - newholland al 59 4x4 3

( Anybody happen to have a line on some outriggers? – If so, please PM me)
 

oldMan99

Member
479
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Location
Polk County, Florida
Yes that is correct it is two identical pumps joined together by a removable splined shaft. You can take the pump apart and remove the rear pump and put it back together. The gaskets are reusable, you will need to buy 8 shorter hex bolts and locktite everything back together, takes about 15 minutes, super easy.
Cool, good to know!

I would agree with your statement for a rear winch, if it ever gets that bad you are not going to want to go forward anyways.
When stuck, backwards is almost always easier than "More stuck"...lol (Not always of course, but usually)

The 20k winch never came hydraulic just pto, you can put a hydraulic motor on it and convert it. The 20k is also conservatively rated like everything else the military puts out. I would save the big bucks for a trick between the rails rear winch and make that your biggie.
Isn't the 20k winch on the 900 ( M925/928 ) series hydraulic? How do you go about converting from PTO to hyd? I know you need a hyd motor but what motor is the question? Is it something that can be gotten from a place like Northern Hydraulic? Does it bolt up directly to the winch or do you run a shaft from the motor to the winch "Fooling" the winch into thinking it is running off the PTO shaft
 

eldgenb

Member
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16
Location
Spokane WA
Cool, good to know!


When stuck, backwards is almost always easier than "More stuck"...lol (Not always of course, but usually)


Isn't the 20k winch on the 900 ( M925/928 ) series hydraulic? How do you go about converting from PTO to hyd? I know you need a hyd motor but what motor is the question? Is it something that can be gotten from a place like Northern Hydraulic? Does it bolt up directly to the winch or do you run a shaft from the motor to the winch "Fooling" the winch into thinking it is running off the PTO shaft
No the 900 series is still pto, just the m35a3 is hydraulic afaik. To convert it is not a big deal, you can go here to find the odds and ends to put it together. As far as what motor, I would call those guys and quiz them, its a little over my head. Typically you could just run a motor with the same sized shaft and collar it, or unbolt the drive shaft from the winch, drill and bold a plate to replace it and weld on whatever system you want to use.

Not to be a party pooper but we are really beginning to Hijack the thread, we may want to move this back to one of the other two threads on this subject.
 

Excuse Me

New member
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Hillsboro Oregon
OK, if I understand this correctly, the M920 is a fixed displacement system. Is this because the winch does not actually “use” fluid, (meaning like a ram would “use” or temporarily store fluid to extend the ram and then return it to the system when the ram retracts). (More about ram usage below) If you wanted to run both a stock 45k winch that needs the full 44gpm and (not at the same time, but on the same vehicle) a 30k winch that uses 20gmp what do you need to do to make the lower flow tool work properly?
Ok, pump part of the system is the only part that dictates a fixed displacement. In other words, the winch motor and cylinders can be used with a variable displacement pump system as well as the fixed displacement. Yes, the M920, which states a "gear pump" is fixed displacement.

The motor on the winch does "use" fluid just the same as a cylinder. The word "use" means that there is a high pressure side in front of the work, and low pressure side behind the work. Though it is true, when using the winch the fluid level in the reservoir will stay the same while the winch is in operation, whereas the cylinders, when operating the "open" end, or the end without the rod, the level may drop ever so slightly as the cylinder extends, this is not "use" of the fluid, only a minor location differential of the fluid.


I assume this changes some if your using rams (like to level the vehicle) because the rams “Keep” some of the fluid. Of course (I assume here) that if your using the rams, your not using the winch at the same time so the loss of fluid would not matter because by the time you winch the rams will have given their fluid back and the reservoir is plenty large enough to fill my 4 cylinders and then some… Correct?
This is the cool part of the tandem pump. If the winch is on one circuit (pump section), then you can work the winch and the cylinders at the same time, and not either circuit effected by the others work pressure or flow.

You have the right idea that the cylinders when extended will "keep" some of the fluid, but not so much as it may appear. When you extend the cylinder (average type, common cylinder) the fluid from the rod end will return to the reservoir. As long as the number of, and size of, the cylinders are within the scope of the reservoir size, all will be good. At 44 gallons, if you use 4 cylinders for leveling that are sized reasonably for the work they need to perform, you will barely notice a drop in the reservoir level.

Can you move 1 ram at a time SLOWLY or will it slam into the ground? Do these control valves work proportionately like on an excavator or are they all or noting?
An excavator is a variable displacement, pressure compensated system. I dont wish to go off on that and confuse the issue, but it is different than the system on the trucks here.

In an open center system like the trucks have, yes, you can extend a cylinder slowly using common control valves like what may be on the trucks. I hope I did not confuse the issue when I mentioned the use of hose size and coupling size aas a speed control. There is a difference, however, I think what is being discussed here, is using a small cylinder to move a camper section with such a large sized pump and valving setup. That I think is where some of the confusion may start. If you use the trucks valves and system components to control a larger levelling cylinder, it will be within the scope of the systems design and work fine. In other words, using one side of the pump at 22gpm to move a 1" bore cylinder can be much like using a 3/4" drive impact wrench to tighten a #10 screw.


I am thinking about building my (sleeping) bed sideways across the front of the box and using some kind of motors to raise it up to the roof leaving the dining area below. I would be interested in discussing the linear actuators (possibly in another thread so we do not hi-jack this one away from things relayed to the truck itself) to learn more about them. That same conversation would likely help with the roof question as well.
Yes.


I was thinking of either a simple straight ram with a foot/base that would (manually) swivel up when not in use like the smaller trailer tongue jacks, OR finding real outrigger legs from a utility truck/crane/big wrecker and fitting them to the truck. I understand the linkages your talking about but that seems intensive in design and implementation.
Actually, the linkages may get you just what you need without the space usage of a direct cylinder hookup. However, that too may be best drawn out in a different thread.


I searched youtube and easily found several videos of that. Most only show the combine moving along the hill already “Adjusted”. After 4 or 5 I found one that shows a combine adjusted and then make a u-turn on the hill and go back, all the while keeping the cab level. That was actually pretty cool. I am guessing in addition to the controller you would need some electric/hydraulic control valves and that even used parts can’t be inexpensive. But it would be a cool system. I know they make auto leveling jack systems for RV’s, it may be possible to get the necessary electrical components and use them to run our larger jacks once they have been pivoted into the vertical position. For those interested: YouTube - newholland al 59 4x4 3

( Anybody happen to have a line on some outriggers? – If so, please PM me)
But it's the cool factor.................[thumbzup]
 
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