Fmtv crane maintenance manual, hydraulics specs?

[8madjack]

I am looking for the FMTV service manuals, currently only seems to be the -10 operating manual.

Specifically I am looking for the 5000 lb crane maintenance and hydrauluc pymp specs.

I see and have all the detailed manuals for my m931a1, but was hoping to find the same detail for the crane.

Any ideas, suggestions are welcome thanks.

 

[coachgeo]

I am looking for the FMTV service manuals, currently only seems to be the -10 operating manual.....

As the old saying goes "If it twas a snake it would have bit ya!!!" go to first page of this bulletin board......On the top, of this boards first page .... the very first item on that page is the TM (Technical manuals) forum. There is a post in there with links to all the FMTV manuals.

 

[8madjack]

****, I went through them, but now I see I was looking for the 1083, the 6x6 versions. I'll look through and see if any 4x4s had a mhc.

In the meantime I found a bunch externally, I might have more for the library soon.

 

[firefinder]

8madjack,

To my knowledge, the LMTV (4x4) units were not fitted with a Material Handling Crane (MHC). There is a Light Material Handling Crane (LMHC) that is mounted on an upright post. The LMHC was mounted in the 4" x 4" square holes in the bed of the LMTV or MTV (6x6).

The MHC, 5,000 lb version was found on the M1084 and M1086. The M1089 wrecker has an MHC with a capacity of 11,000.

I have an M1084 and have refitted some of the cylinders, etc. Will be glad to send photos or share specifications I have found in the process.

firefinder

 

[8madjack]

8madjack,

To my knowledge, the LMTV (4x4) units were not fitted with a Material Handling Crane (MHC). There is a Light Material Handling Crane (LMHC) that is mounted on an upright post. The LMHC was mounted in the 4" x 4" square holes in the bed of the LMTV or MTV (6x6).

The MHC, 5,000 lb version was found on the M1084 and M1086. The M1089 wrecker has an MHC with a capacity of 11,000.

I have an M1084 and have refitted some of the cylinders, etc. Will be glad to send photos or share specifications I have found in the process.

firefinder

I really appreciate that. There is a cannon plug that went from the truck to the crane that the guy I bought it from has 12 volt power, but I need to find out if theres anything more to it. Theres more than 2 pins, think 4 or 5

 

[tobyS]

I think what you have is a Grove MHC 977, like Grendel has. They are off of early HEMTT's . It's too heavy for my deuce project.

Quote from one post; "Grove made the MHC977 as a government contract unit speced out by TACOM so there are no Grove parts manuals or handbooks for it."

https://www.steelsoldiers.com/showthread.php?36775-Grove-M977-Crane

 

[8madjack]

This one is definitely a 5000 pound model off of an fmtv I saw it on the truck. It did strike me that there is a similarity and that a lot of info might cross over. I can't believe that there's no manual on the One You're mentioning there's always some documentation it just might be impossible to find

 

[tobyS]

There are a lot of threads on the MHC 977 Grove crane. Here is one useful post. I noted the HEMTT system is usually 2500 and maxes out at 3000.


"My tank holds 20 gallons and it uses as much as 1/2 of it when everything is fully extended."

 

[tobyS]

This one is definitely a 5000 pound model off of an fmtv I saw it on the truck. It did strike me that there is a similarity and that a lot of info might cross over. I can't believe that there's no manual on the One You're mentioning there's always some documentation it just might be impossible to find

It looks like the same crane. Grove cranes came on the early HEMTT. They replaced them with a HIAB, which is probably why the Groves are available. Safety interlocks will be some of the hardest to adapt, but it has been done. I just found a thread with a deuce with one that may have good info.

https://www.steelsoldiers.com/showthread.php?3950-HEMMT-M977-Crane-Swap-Deuce-Project

 

[8madjack]

Yes, read that early in my searches. It actually made me feel that model was not suitable for me. Too hard to adapt, loss of frame space.

The fmtv crane is one structure and sits on top of the frame, outriggers are integral and at an angle. If the setup was "perfect" it would have outriggers that rotate up 180° and extend/retract! I think this will work great though, just need to see what mods I'll need to do to tanks and stuff. I'll probably make a mockup in addition to measuring to check fitment easily.

 

[tobyS]

Yes, read that early in my searches. It actually made me feel that model was not suitable for me. Too hard to adapt, loss of frame space.

The fmtv crane is one structure and sits on top of the frame, outriggers are integral and at an angle. If the setup was "perfect" it would have outriggers that rotate up 180° and extend/retract! I think this will work great though, just need to see what mods I'll need to do to tanks and stuff. I'll probably make a mockup in addition to measuring to check fitment easily.

Okay.

Post up some pictures when you get a chance. If you come up with a hydraulic or electric schematic, please post it.

 

[tobyS]

I am still looking for hydraulic schematics for the crane winch. I have taken the winch completely apart, including the brake unit and put in new o-rings. I found the brake wet clutch pack has three chambers that oil goes in and there are 1/8" ports for them. One makes the pressure on the brake higher than the springs put on it. The next puts pressure on the outside of the piston, releasing the brake. The third goes into the clutch pack area, apparently to keep it wet but with pressure, would also release the clutch, acting against the spring.

The main shaft from the pump to the brake unit has a one way clutch. It rotates freely in one direction and locks in the other. Thus the brake really only functions against line pull and can freewheel the other direction. No hydraulic inputs change that. It can be winch-in and even with the brake engaged by the spring, the free action will allow it to winch in. But it won't allow winch out without releasing the brake, via one of the two ports that act against the wet clutch springs.

Thus to winch in, no pressure is needed on the brake, but to winch out, the brake must be released.

The unit doesn't look capable of having full line pressure, so I believe there is a control circuit. I read that the HEMTT has a 195 psi circuit, which leads me to think that the brake is controlled at that pressure. If I simply hook to the winch out hydraulic line to release the brake, it may put too much pressure into the brake and blow seals.

I hope to confirm the routing and sources of pressure to operate this winch. At first I thought the valve on the motor was a cross port check valve that would act to block the ports without either pressure to winch in or winch out. Now I think it is a pressure relief valve that relieves once a certain pressure is reached. It should have both in my opinion, but doesn't.

While I don't have a complete crane to work with, I think the LMTV and the HEMTT are essentially the same Grove crane, perhaps with a change of outrigger design.

Please help me chase down the small control lines on the brake and find a hydraulic diagram or these very nice (5K) winches will remain boat anchors.

 

[8madjack]

I havent had time to dig throught the books yet, but I can take pics if you want, it's been rainy and its covered up right now.

 

[tobyS]

I havent had time to dig throught the books yet, but I can take pics if you want, it's been rainy and its covered up right now.

Rain...in sunny California??? Just kidding. Much thanks for your help 8madjack.

Gringletaube provided a very useful link in this thread: https://www.steelsoldiers.com/showthread.php?157838-Crane-info/page2.

I found the schematic on page 811 and some other useful info before that. But I have to admit, the TM goes from side view to other side view and shows lines going to the winch and brake, but I have a really hard time following them. The schematic helped with 90% and revealed some key info....like there is no pilot operating the brake, it's full line pressure (maybe) and it goes into the middle set of holes in the brake and the line does come from the check valve on the motor. Some of those check valves operate at 1/1 and some are 10/1, so I'm still not exactly confident I know pressures correctly.
And it is a pilot operated check for one flow direction...winch out.
What has me baffled is why the motor drain hooks to the spring side of the brake, but does not hook to a return line. That's where following the lines on the side views gets confusing to me.
I'm working on plumbing it up with some stainless hydraulic fittings recovered from these brake units and ordering Weatherhead hyd fittings for what I don't have.

If anyone needs a failsafe hydraulic brake with dual hydraulic accumulators...I have a couple left complete. Note this is not an ad....I doubt anybody has this type of brake.

Really 8madjack, don't be in any hurry but I would appreciate it if you could run that motor drain/brake actuator (not release) line down. Also, please note it the lines go high so they will hold hyd fluid in the units, not drain them out. Something has to supply the oil and drain it...maybe leakage on the motor??

 

[8madjack]

I'm in the process of downloading the 6x6 mtv manuals (slow connection), seems only the 4x4 are uploaded here. I have noted so far that the TM-9-2320-366-34-4 has a lot of info on maintenance and repair of the crane, but didn't see specific info on the winch yet.

I am accessing and downloading the PDFs here, https://www.nsncenter.com/Library/FMTV

 

[8madjack]

I am getting all the manuals for the library, but I;m going to try and note where all the crane info is.

 

[8madjack]

26-6 pg 26-33 starts the brake assembly repair, no removal or installation though.

 

[8madjack]

Pay dirt! TM-9-2320-366-34-3 has all the removal/replacement of the MHC and its componants, the appendix has the electrical and hydraulic schematics. start looking at PDF page 1151 for the hydraulic system foldouts, 1161 shows the first schematic that includes the winch/hoist and several foldouts after that too. let me know if this helps.

 

[tobyS]

It will be a couple days before I'm back into this. Thank you very much. I hope it helps with your project too as there are safety interlocks that make this a more complicated swap than first impression.

I have the chance to get an M977 Grove from Grendel and bring it here on the trailer I'm buying from him, but I think I'll pass, given the complexity and my opinion of some design issues.

I sure could make a deal for someone else to buy it and bring it to Indiana on the trailer, however. Any takers in the midwest???....we're working out a lot of details for you.

 

[8madjack]

It helps a great deal and it looks like other than the hydraulic power there's a Cannon plug with 12 volt power going to it.

I talked to a shop today and they recommended I set it up with the pto setup. He said he can convert it to a direct flange Mount or stick with the driveshaft depending on how much room is in there. The pump is going to be about 500 bucks I'm still going to look to see if I can find a military pump with the drive shaft