"Rescued" M816 Wrecker

[red]

Here's fine

 

[wcuhillbilly]

Either way will work for me Jeff, Think my woes aint over yet, was using the crane last nite and heard that tell tale ticking coming from under the bed, crude isolation in the dark points to T case PTO output that goes to the Pwr divider. I need to look at it in the daylight to see if it may just be a u joint tapping but I could feel and hear the ticking in the transfer case (T138 ). Sound goes away when the Divider is disengaged, thus no load, and shaft just spinning free. Put the divider in and introduce a load and the sound comes back....

So,,, if the T case is going south,,,,, Im really starting to think about putting the Eaton 10 in and scrounging up a wet kit.... If this is the case then the Power divider goes away, and the rear winch and crane are run off the Wet kit. This brings up the problem with the crane drive being shaft right now, and how to convert it to either the 936 hydro drive, or sourcing commercial hydro motor to power the existing gear box that passes through the crane turret. The rear winch is farely easy, and the front winch is farely easy.
None of these hydro functions would be operating at the same time, thus switch valves to select each would likely be appropriate. the only two that may need to be live at the same time would be the rear winch and crane. --- IE to tug for a few minutes, then lift, tug, then lift, but I doubt that I would have to tug and lift at the same time... physically cant reach that far....

 

[red]

Your luck lately has been bad, no other way to put it haha.

If it is the tcase and you want to save some money I have a T138 sitting here from that dump truck I've parted out, shoot me a pm or text if interested. Hopefully it's just a ujoint though.

As for doing the swap to a 10 speed, I would not buy another hydraulic pump. Take the one from the crane base and mount it on the truck chassis. Plumb in a 2 valve manifold between the pump and the swivel for the crane that way all 3 systems are ready to go (used 1 at a time).Would only need a 2 port hydraulic swivel to plumb back into the crane. So hydraulic layout would be pump-manifold-swivel for the main fluid flow. That keeps the crane operational at maximum flow. The 2 valves off the manifold would be directed to the winches.



Fired up my m816 today for the first time since mid november. Fired up quickly on the first crank then died out. Cranked it a second time for about 10 seconds and it was running just fine after that. Unloaded some of the dump bed components from the bed of the toyota pickup and loaded up the transmission from the m51a2 into the truck bed.

 

[wcuhillbilly]

Thanks Red, I will have to ponder this idea, the crane pump is up in the turret and currently powered by the 90* gearbox, not really sure how to remote mount it without messing up the supply tank.
Checked the t case tonite after work, there is some up/down movement in the t case PTO, but after checking a forcing grease into a stuck nipple the sound has stopped, now a ticking is muffled in the 90* gear box,. Not like it was the note it all went south but faint enough to perk my ears. Odd point,,, but didn't notice till tonight that the t case PTO spins clockwise and the shaft into the 90 box spins counter, making me guess that the crane pump spins clockwise....

 

[red]

Remote mounting the pump would be pretty simple. A hydraulic pump only has 2 hoses running to it. Low pressure coming from the tank and the high pressure leaving the pump. The 90 degree gear box would be replaced by a 2 port hydraulic swivel (current hoses are probably long enough to be reused here). The low pressure coming from the tank would flow down through 1 of those ports and over to the pump. The "high" pressure would leave the pump and go up through the 2nd port on the hydraulic swivel and continue on to the rest of the system as normal. That would be it if you only wanted to relocate the pump and keep using the PTO shafts for the winches.

If you want to run everything off of the crane hydraulic pump there is only 1 difference. The high pressure would leave the pump and be directed into a 2 valve manifold mounted somewhere on the bed/cab/fenders, anywhere except on the crane. Then the main line of high pressure would go from the manifold to the hydraulic swivel on the underside of the crane and continue on as normal.

From that manifold there are 2 hoses per valve, 1 high pressure and 1 return. The high pressure will go from the manifold to the device being operated (winch). The return brings the fluid back to the manifold where the oil joins back with the main flow of 'high pressure' fluid and continues on towards the crane equipment, then finally back to the tank.

If you convert everything to hydraulic you need at least 7 new hoses, assuming that the 2 currently running to the pump are long enough to reach the new hydraulic swivel. 3 hoses that are the same diameter as what is currently running to/from the pump. 2 hoses for each hydraulic motor running a winch (4 total with 2 winches).

Correct on the rotation.

 

[Csm Davis]

Okay if you need to switch to all hydraulic I would do like Red said and mount your pump on the frame and then plumb everything like a M936 you might even want to look at getting a complete 936 body.

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[red]

Okay if you need to switch to all hydraulic I would do like Red said and mount your pump on the frame and then plumb everything like a M936 you might even want to look at getting a complete 936 body.

How much would it cost to get a replacement wrecker bed? Figuring the weight of the bed is somewhere in the 16-18k range a bed swap is doable with another wrecker using the boom supports.

I wonder how feasible it would be to modify a wrecker crane into something like a truck mounted excavator. Roaming through the forum and found this, that's where the idea came from haha.

 

[wcuhillbilly]

Red after pondering your theory on hydro conversion, I stopped by a towing service in Newcastle WY, on my way back from a training session. What a mess under the 936 with multiple PTO and frame mounted hydro pump with tank on crane, did get some pics of winch motors so I hope I can track down an equivalent.

 

[red]

Yea hydraulic setups can become chaotic the more systems you add. With the drilling rigs I worked on there was 2 separate systems. 1 for the top drive running 2 1/2-3" hoses and the other was a "smaller" PTO powered pump running to a different valve bank with between 12-18 valves. Each valve was air actuated so including the air lines there was 50-74 hoses all running to a small roughly 2ftx1ft area.

If you relocate the pump to the frame and add that 2 valve manifold onto the truck somewhere it won't be bad. 2 hoses running to the rear of the truck for the 45k, 2 hoses running to the front 20k (probably 1/2" for these 4, maybe 3/4" for the 45k), then the 3 main hoses between the swivel/pump/manifold.

If you really wanted to at this point you could either move the crane controls down to the truck or make a duplicate valve bank on the truck for crane controls. That would take a 10 port swivel at the base of the crane. That would be a bit of chaos with the hoses but could be done with some organization. Would never have to climb up into the operators bucket again, all controls would be accessible from the ground.


Depending on how cheaply you could get a m936 bed for that might be the cheapest route. Assuming the hydraulic swivel is 1k then the cost for relocating the m816 pump would be in the 2-3.5k range after you include the new PTO shaft, pump mount, hoses, valve manifold, 2 hydraulic motors.

 

[BnaditCorps]

How much would it cost to get a replacement wrecker bed? Figuring the weight of the bed is somewhere in the 16-18k range a bed swap is doable with another wrecker using the boom supports.

I wonder how feasible it would be to modify a wrecker crane into something like a truck mounted excavator. Roaming through the forum and found this, that's where the idea came from haha.

View attachment 667774 View attachment 667775

I would think you would have to get a whole new wrecker. You could get a non-runner though and it would be fairly cheap (talking in relatives).

Don't know the rating on those supports, so I would research that before you do anything, although if they can hold up the whole rear-end of the wrecker I see no reason why they couldn't be used in that situation.


That looks like fun, but I bet is would be very tedious to put together.

 

[Csm Davis]

I would think you would have to get a whole new wrecker. You could get a non-runner though and it would be fairly cheap (talking in relatives).

Don't know the rating on those supports, so I would research that before you do anything, although if they can hold up the whole rear-end of the wrecker I see no reason why they couldn't be used in that situation.


That looks like fun, but I bet is would be very tedious to put together.

I know the military made at least 4 M35 dredge trucks, I cut one up unfortunately, and there are couple on here. I have been thinking about making a 5 ton version of the SEE, I guess I should call it a LEE (Large Emplacement Excavator).

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[WILDBOY6X6]

I would love to have one fyi I would recommend you bar the engine over by hand 1st, if you feel any resentence STOP it means you may have to remove the heads or just the rocker boxes.
Then if it turns over ok you can try to start it, but as others said change the filters and new fuel too. by the way the NHC 250's do not have an IP only a fuel pump.

 

[red]

I know the military made at least 4 M35 dredge trucks, I cut one up unfortunately, and there are couple on here. I have been thinking about making a 5 ton version of the SEE, I guess I should call it a LEE (Large Emplacement Excavator).

Sent from my SM-G930V using Tapatalk

Would love to see that. Do you think modifying a standard wrecker bed to become an excavator would be a viable option? I glanced at used excavators in my area and the cost is about 30k on average for a rough unit of proper size.

I have a picture in my head of a modified crane (standard 816, 936, 543) with the winch removed and the pulleys at the end of the boom cut off. Heavy duty pin installed there with a hydraulic cylinder added to the top of the boom to pivot the excavator arm, maybe 8ft long plus the bucket. Would require the metal work, 2 more hydraulic cylinders, and a new valve bank to provide 1 more circuit.

For those wondering no I will not do that to the current wrecker bed on the m816. If I had a second bed to swap between in the future, maybe but other projects/ideas are higher priority.

 

[BnaditCorps]

I know the military made at least 4 M35 dredge trucks, I cut one up unfortunately, and there are couple on here. I have been thinking about making a 5 ton version of the SEE, I guess I should call it a LEE (Large Emplacement Excavator).

Sent from my SM-G930V using Tapatalk

That sounds like a fun idea, and it might just work.

 

[Another Ahab]

I know the military made at least 4 M35 dredge trucks, I cut one up unfortunately, and there are couple on here. I have been thinking about making a 5 ton version of the SEE, I guess I should call it a LEE (Large Emplacement Excavator).

That sounds like a fun idea, and it might just work.

You haven't even started the thread, and I'm already subscribed.

 

[wcuhillbilly]

wow, the evolution of thread highjacking has begun....

Meanwhile back at the ranch,,,,,,
I am just glad to have my wrecker back up and running for now. I was going to go after the 10 spd Thurs but snow and a few other things got in the way. In looking at the 936 I found such a mess under that truck with the trans powering a PTO that ran rearward to a hydro pump that then ran lines forward to the front winch motor, a under mounted PTO driven from the transfer case supplying hydro to rear winch and crane, and the hydro tank mounted on the crane.....

My thoughts,,,, convert pass side fuel tank to Hydro tank. (cap 80?? gal) remove hydro tank from crane-lowers center grav, increase bed space, and reduces diam of hydro swivel needed to pass through crane turret.. Mount crane hydro pump on frame, powered by either PTO shaft or wet kit from trans. (this allows me to continue to run my existing T case even if the PTO is starting to fail) Manifold as Red stated with a manifold block for switching from front winch or rear or crane.... Preferably with crane and rear being capable of dual live power as to pull/lift without having to switch gears- or valve blocks in this case. Have the ability to plumb in another block, for installation of outriggers later on down the road.

RED also mentioned putting the crane valve body down on the chassis/bed which would require the use of a ??? 10 port swivel, I doubt I could afford that, but having the controls on the bed would be sweeeet, not having to climb up on that slippery beast in the ice and snow....
Also,, building a "headache" rack behind the cab, for a lightbar,,, but more importantly, a chain rack, that keeps all my straps and chains well organized and readily available.

 

[Csm Davis]

wow, the evolution of thread highjacking has begun....

Meanwhile back at the ranch,,,,,,
I am just glad to have my wrecker back up and running for now. I was going to go after the 10 spd Thurs but snow and a few other things got in the way. In looking at the 936 I found such a mess under that truck with the trans powering a PTO that ran rearward to a hydro pump that then ran lines forward to the front winch motor, a under mounted PTO driven from the transfer case supplying hydro to rear winch and crane, and the hydro tank mounted on the crane.....

My thoughts,,,, convert pass side fuel tank to Hydro tank. (cap 80?? gal) remove hydro tank from crane-lowers center grav, increase bed space, and reduces diam of hydro swivel needed to pass through crane turret.. Mount crane hydro pump on frame, powered by either PTO shaft or wet kit from trans. (this allows me to continue to run my existing T case even if the PTO is starting to fail) Manifold as Red stated with a manifold block for switching from front winch or rear or crane.... Preferably with crane and rear being capable of dual live power as to pull/lift without having to switch gears- or valve blocks in this case. Have the ability to plumb in another block, for installation of outriggers later on down the road.

RED also mentioned putting the crane valve body down on the chassis/bed which would require the use of a ??? 10 port swivel, I doubt I could afford that, but having the controls on the bed would be sweeeet, not having to climb up on that slippery beast in the ice and snow....
Also,, building a "headache" rack behind the cab, for a lightbar,,, but more importantly, a chain rack, that keeps all my straps and chains well organized and readily available.

My-my ain't that the pot calling the kettle black!
As to moving the hydraulic tank down, I don't see a reason why you couldn't but no good reason to do it. The hydro swivel will need to remain the same because you are still moving the same amount of fluid up and down.
I have always wanted to know why the 936 has 2 different PTO'S? One thing you might check is the max torque output on the transmission PTO vs the torque required for the main pump for the crane body. I would think that might be the reason for the transfer case PTO.
As for the ten port swivel and light bar/headache rack i would love the swivel and I am going to build a ROPS bar/boom support for mine.

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[Another Ahab]

I am just glad to have my wrecker back up and running for now. I was going to go after the 10 spd Thurs but snow and a few other things got in the way. In looking at the 936 I found such a mess under that truck with the trans powering a PTO that ran rearward to a hydro pump that then ran lines forward to the front winch motor, a under mounted PTO driven from the transfer case supplying hydro to rear winch and crane, and the hydro tank mounted on the crane.....

I live in a house that was put together in almost the same way. Nothing in the layout and construction makes any real sense. It drives me bananas (Momma calls it her "dream house").

I wonder if the same guy who built this place moved, and then sold you his truck. Where did you say you bought it?!

 

[red]

wow, the evolution of thread highjacking has begun....

Meanwhile back at the ranch,,,,,,
I am just glad to have my wrecker back up and running for now. I was going to go after the 10 spd Thurs but snow and a few other things got in the way. In looking at the 936 I found such a mess under that truck with the trans powering a PTO that ran rearward to a hydro pump that then ran lines forward to the front winch motor, a under mounted PTO driven from the transfer case supplying hydro to rear winch and crane, and the hydro tank mounted on the crane.....

My thoughts,,,, convert pass side fuel tank to Hydro tank. (cap 80?? gal) remove hydro tank from crane-lowers center grav, increase bed space, and reduces diam of hydro swivel needed to pass through crane turret.. Mount crane hydro pump on frame, powered by either PTO shaft or wet kit from trans. (this allows me to continue to run my existing T case even if the PTO is starting to fail) Manifold as Red stated with a manifold block for switching from front winch or rear or crane.... Preferably with crane and rear being capable of dual live power as to pull/lift without having to switch gears- or valve blocks in this case. Have the ability to plumb in another block, for installation of outriggers later on down the road.

RED also mentioned putting the crane valve body down on the chassis/bed which would require the use of a ??? 10 port swivel, I doubt I could afford that, but having the controls on the bed would be sweeeet, not having to climb up on that slippery beast in the ice and snow....
Also,, building a "headache" rack behind the cab, for a lightbar,,, but more importantly, a chain rack, that keeps all my straps and chains well organized and readily available.

Would it be a thread hijack if the owner of the truck participated in the redirect? hahaha.

Hydraulic layout can be chaotic, especially when there are design problems like what happens on military contracts. Designer A doesn't talk to Engineer B and assembler C has to figure out a way to make it work without talking to either of them.

Like Csm Davis stated moving the hydraulic oil tank down to the frame will not affect the amount of ports required on the hydraulic swivel. Must have at least 2 ports.

The headache rack idea would be a great place to mount the hydraulic manifold (valve bank is another name for it).

The beauty of these hydraulic systems is that they are a low pressure, 2500psi (max) setup. Cuts the cost down alot. High volume but low pressure.

Csm Davis I have an idea for why the m936 has 2 separate hydraulic systems. Considering how the military likes to keep certain things interchangeable I think they did that with the winch system. All the other w/w m939 trucks use the same transmission PTO/reservoir/pump/winch motor. They probably just kept that mentality and carried it over to the m936.

Csm Davis are you still parting out wreckers?



Need to check what size hose is attached to the pumps.

For those wondering what a multiple port hydraulic swivel (also called rotary unions) is heres one manufacturer http://www.dsti.com/products/rotary-unions/gp/

 

[red]

Another option that would be much cheaper than a 2 passage rotary union would be a pair of these single passage rotaries http://www.surpluscenter.com/Hydrau...E-12M-LIVE-SWIVEL-90-ELBOW-9-LV6801-12-12.axd

Let me be clear on this option. The crane on these trucks WOULD NOT be able to do a complete 360. 180 degrees would be pushing it using 2 of the single pass rotaries for the crane. The reason for the limited range is because the 2 hoses would make contact with each other and start to twist around each other, leading to one or both of the hoses getting ripped apart.

So if you NEVER did a lift off the sides of the truck, always worked off the rear, this would be a viable 'cheap' option with moving the crane hydraulic pump down to the truck chassis.