M816 Hydraulic Pump

Does anyone know what the GPM/pressure is of the hydro pump mounted under the crane of the M816. I plan on removing the crane and installing a DP 45k or bigger winch in the bed and maybe I could use the pump already there or put one under the bed. Thanks

Use it if it's mechanically sound and not in your way. A PTO pump would not be big enough, I don't believe, unless you were willing to go slow. Somebody with one may have the pressure and flow info., I don't.

It would be an open center valve since it's a gear pump. is there more than one section to the pump? Take a look see if you can use the valve and just take some sections out. Look for the largest ports. Are there other hydraulic things that the valve could operate with it's multiple sections? Maybe use two sections of the valve to have a high and low speed..... Just a few ideas.

How big are the ports of the winch, pump and valve?

I haven’t went and picked up the winch yet. The problem i think is having a pump that will make enough pressure/flow at low rpm so i can use the rear shaft drive 45k winch already there.

It's around 45hp output so around 45gpm. The rear winches on the 916s run off about 29gpm. The rear winches off the 939 and 816s run off the same power around 29

Flow rate doesnt matter as long as its 2500psi. The lower gpm rate the slower the winch

Are you describing using 2 winches simultaneously, the 45 that is there on the wrecker (shaft drive) plus another 45 hydraulic driven?

tobyS said:

Are you describing using 2 winches simultaneously, the 45 that is there on the wrecker (shaft drive) plus another 45 hydraulic driven?

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Correct. I dont know what/if it will break, but they will run at the same time. I dont think iam gonna be able to keep my shaft winch turning slow and keep enough pressure for the Hydraulic winch at the same time. Unless i do something different for the pump.

Why not operate the two winches the same way, both PTO or both hydraulic driven? That would cure your differences in RPM. I plan on having 2 hydraulic 45k garwood on mine using the standard 936 rear winch controls.

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Csm Davis said:

Why not operate the two winches the same way, both PTO or both hydraulic driven? That would cure your differences in RPM. I plan on having 2 hydraulic 45k garwood on mine using the standard 936 rear winch controls.

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I may have to do that, i rather try the hydraulic way first.

I understand your problem. While you could keep rpm higher by using a lower gear in the tranny, you don't have a way of pulling power off at engine speed...like a front mounted pump coming from the crank.

Jeff Davis has given another option, changing them both to hydraulic or to PTO (mechanical). That would seem to require a pump with 2 circuits and valves to do simultaneously....but it could be made work.

A pony engine is another option. I have an Isuzu 4 cylinder diesel that I have a pump mounted on, about 50hp. I'm not sure (been a while), but 98G was working on a pony engine that used a Honda gold wing motorcycle engine. The nice thing about the Isuzu is that they are common on refer units and can run all day long on little (diesel) fuel. The Isuzu has an SAE bell-housing, which has pump adapters and drives available also.

Why are you removing the crane? You could mount the winches outboard and keep it. Also running them both mechanically would be cheaper but harder to balance than hydraulically driven which is the direction I have collected parts for.

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Csm Davis said:

Why are you removing the crane? You could mount the winches outboard and keep it. Also running them both mechanically would be cheaper but harder to balance than hydraulically driven which is the direction I have collected parts for.

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You're still sucking air! That's awesome!

Well, i cracked the driver side winch case some how. The cable broke on a long pull and i think thats what cracked the housing. Winch still works and the brass gear inside still looks good. I think now is a good time to go with a hydraulic winch in its place. I can use the winch shaft that went to the rear and install a pump on it to power both winches at the same time. Does anyone know what rpms the winch shaft is running when the trans is in 4th and 5th gear?

Csm Davis said:

Why are you removing the crane? You could mount the winches outboard and keep it. Also running them both mechanically would be cheaper but harder to balance than hydraulically driven which is the direction I have collected parts for.

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The crane is not big enough of what for what we do, i have yet to use it on anything but it does work. Iam gonna mount a 60k hydro winch were it is sitting.

lighten said:

The crane is not big enough of what for what we do, i have yet to use it on anything but it does work. Iam gonna mount a 60k hydro winch were it is sitting.

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As far as lifting for the crane there is a thread here where someone put twin winches on the crane for improving its lifting. Just seems to.me it would be easier and cheaper to buy another cargo truck or tractor and add a set of M916 winches and fashion them to be side by side behind the cab and run them. The complete winch unit for a 916 including platforms are around $1000. If that. The m1070 HET side by side 55ks are available however they are shaft driven by a PTO.

For running the double winches you can use the wrecker pto on the transfer case as well as the transmission pto. Or mount a 3 or 4cyl diesel engine pony motor with it's own pump system.

lighten said:

The crane is not big enough of what for what we do, i have yet to use it on anything but it does work. Iam gonna mount a 60k hydro winch were it is sitting.

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lighten said:

Well, i cracked the driver side winch case some how. The cable broke on a long pull and i think thats what cracked the housing. Winch still works and the brass gear inside still looks good. I think now is a good time to go with a hydraulic winch in its place. I can use the winch shaft that went to the rear and install a pump on it to power both winches at the same time. Does anyone know what rpms the winch shaft is running when the trans is in 4th and 5th gear?

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Okay so at this point you should just remove the bed and start over, what type of work are you doing? More information helps us help you. But it sounds like you need an oilfield winch truck setup. This is easily built on the back of the wrecker. We have built many at the shop I used to work for and I will be glad to point you in the right direction to build or buy what you need.

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I installed DP 45k hydro winch in the old winch location, iam gonna use the tank from the winch and valves. I have a 2 stage hydro pump ordered that will flow enough to run 2 winches, winch i plan on putting another 45k in the crane location, if any one has a DP45k winch around south GA let me know. I have the tensioner mounted, working on the level wind bracket that the pulley sits on now. Finally got the crane removed, it was all a 524k loader wanted to pick up! I plan on mounting the tanks for both winches right behind the cab in front of storage boxes. Also spooling the winches with 3/4 cable.

Got the DP 55k winch mounted waiting on another tank and pump

I have the tank off a M916 i think its a 60gal unit for $150 plus the ride which might be high.

simp5782 said:

I have the tank off a M916 i think its a 60gal unit for $150 plus the ride which might be high.

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Ok, if my guy doesn’t come thru i will be in contact