North Carolina

Mullaney

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Charlotte NC
I need some help with myM936. Hydraulics not engaging crane. I'm in Mebane, NC. Thank you!
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Couple of questions... The handle down by the door. Pulls up to engage. Is it coming up? Transfer case in the center position. Is the "jackshaft" at the back of the cab - is it turning?

Sometimes you have to bump the transmission shifter into gear - then pull up on the PTO handle on the left of your seat. All the way up...

If the jackshaft is turning, you should hear the pump attempting to move fluid.
Has the crane ever worked before?
 

Drryan

New member
6
12
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Location
Mebane, nc
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Couple of questions... The handle down by the door. Pulls up to engage. Is it coming up? Transfer case in the center position. Is the "jackshaft" at the back of the cab - is it turning?

Sometimes you have to bump the transmission shifter into gear - then pull up on the PTO handle on the left of your seat. All the way up...

If the jackshaft is turning, you should hear the pump attempting to move fluid.
Has the crane ever worked before?
Thanks! If I wanted to add a pressure gauge to the hydraulic lines, where would I install it? Tap a fitting? in-line gauge? Best location? I finally got the PTO engaged for the crane and rear winch. It was not pushed back far enough, so I had to put it in 1-5 and ease it into gear. Unfortuantely, I have to shift the transfer case to neutral when air pressure is low. It wont budge when the primary tank hits 60PSI. Initially, the PTO wouldn't move at all, but then I lubed the actuators under the cab really good and it finally started to move. Now, I hear the pump running and the crane will move, but slowly. I drained the hydraulic tank and changed the filter. About to try the crane again today. It appears that the cable spools have never been unwound on the crane or the winches! :O I'm kind of worried about their de-crepid state. Anyone have a suggestion on what type of lubrication to put on the cable on the spools or should I just change the cable?

Also, I hear a medium-pitch whining sound coming from the box at the right rear of the wrecker. Does that mean there is air in the lines? Do the lines need to be bled anywhere? I want to save this old girl, so trying to do as much preventive maintenance as possible. This is a 1987 M936a1 with about 1400 original miles.
 

Mullaney

Well-known member
Supporting Vendor
5,417
12,342
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Location
Charlotte NC
Thanks! If I wanted to add a pressure gauge to the hydraulic lines, where would I install it? Tap a fitting? in-line gauge? Best location? I finally got the PTO engaged for the crane and rear winch. It was not pushed back far enough, so I had to put it in 1-5 and ease it into gear. Unfortuantely, I have to shift the transfer case to neutral when air pressure is low. It wont budge when the primary tank hits 60PSI. Initially, the PTO wouldn't move at all, but then I lubed the actuators under the cab really good and it finally started to move. Now, I hear the pump running and the crane will move, but slowly. I drained the hydraulic tank and changed the filter. About to try the crane again today. It appears that the cable spools have never been unwound on the crane or the winches! :O I'm kind of worried about their de-crepid state. Anyone have a suggestion on what type of lubrication to put on the cable on the spools or should I just change the cable?

Also, I hear a medium-pitch whining sound coming from the box at the right rear of the wrecker. Does that mean there is air in the lines? Do the lines need to be bled anywhere? I want to save this old girl, so trying to do as much preventive maintenance as possible. This is a 1987 M936a1 with about 1400 original miles.
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Nice!

Glad to hear that you have the pump moving fluid and that it is all nice and clean. IMPORTANT THING to know is that the engine RPM according to the book needs to be set to 1800rpm to avoid burning up that Allison Transmission.

As far as a gauge is concerned, remember that you are dealing with 3000# of pressure. Hydraulic fluid under pressure will cut your skin just like a knife! Out back on the passenger side of the truck is a "valve body" with two handles on it. There is a big steel box bolted to the bed and that is a pretty good place to affix a gauge. Same pressure there as on the valve body up in the gondola. No need to bleed the system...

You may want to spend a little time inspecting the rubber hoses. They are wire reinforced, but even with that they will bust under pressure. Look for cracks just like you would a set of tires. If they are cracked and especially if the rubber is worn off and wire is showing - it it time to replace them.

Cable... There is a lube for it. Link below about it and where I found mine... Lube isn't going to restore the cable if it is in bad shape.


I hate to say I have no idea about the transfer case not shifting at over 60psi. It almost sounds backward (guessing). I would have expected it to be unable to shift until you had 60psi. Wes Simpson @simp5782 will have the answer for that question...

Keep us posted on your progress!
 

Drryan

New member
6
12
3
Location
Mebane, nc
.
Nice!

Glad to hear that you have the pump moving fluid and that it is all nice and clean. IMPORTANT THING to know is that the engine RPM according to the book needs to be set to 1800rpm to avoid burning up that Allison Transmission.

As far as a gauge is concerned, remember that you are dealing with 3000# of pressure. Hydraulic fluid under pressure will cut your skin just like a knife! Out back on the passenger side of the truck is a "valve body" with two handles on it. There is a big steel box bolted to the bed and that is a pretty good place to affix a gauge. Same pressure there as on the valve body up in the gondola. No need to bleed the system...

You may want to spend a little time inspecting the rubber hoses. They are wire reinforced, but even with that they will bust under pressure. Look for cracks just like you would a set of tires. If they are cracked and especially if the rubber is worn off and wire is showing - it it time to replace them.

Cable... There is a lube for it. Link below about it and where I found mine... Lube isn't going to restore the cable if it is in bad shape.


I hate to say I have no idea about the transfer case not shifting at over 60psi. It almost sounds backward (guessing). I would have expected it to be unable to shift until you had 60psi. Wes Simpson @simp5782 will have the answer for that question...

Keep us posted on your progress!
Many thanks! Were you referring to the 2 handles that control the rear winch line as the valve body? If anyone has a picture of location of the gauge they installed, it would be greatly appreciated. Any idea what the whining sound is coming from under the big steel box on the R rear passenger side/corner of the truck? Is that my main hydraulic pump in that box? Thanks so much for the quick reply! Learning a lot, but still a newbie to the 5 Ton!
 

Mullaney

Well-known member
Supporting Vendor
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Location
Charlotte NC
Many thanks! Were you referring to the 2 handles that control the rear winch line as the valve body? If anyone has a picture of location of the gauge they installed, it would be greatly appreciated. Any idea what the whining sound is coming from under the big steel box on the R rear passenger side/corner of the truck? Is that my main hydraulic pump in that box? Thanks so much for the quick reply! Learning a lot, but still a newbie to the 5 Ton!
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No sir. Pump is under the truck amidship more or less. The RR passenger side is the valve body that operates the rear winch. The whine could be where one of the valves is partially engaged with the switch on the side of the truck by those two handles. There will be sound there - but it shouldn't be a loud whine.

There should be a few small plugs to attach gauges to. When you unbolt that box, it is going to take two people to lift it off. Let me rummage around for some pictures of that valve. Or the TM's may have a drawing with the pressure ports noted on it.
 

Mullaney

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Supporting Vendor
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Location
Charlotte NC
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That's neat! I have been here in the big city since I was born. Excepting some time spent working for "Uncle Sam", this is where I've been. Grandpa and Grandma lived out on Hickory Grove Road if that tells you any history about our Mullaney Clan.
 

gobsmacked

New member
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2
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Location
bellevue mi
I need some help on my 925 a2, my son in law pulled the emergency kill switch and i do not have a cue how to reset it. i am in clyde NC can anyone tell me how to reset it? thanks x-count
 

wheelspinner

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North Carolina - FINALLY !
I need some help on my 925 a2, my son in law pulled the emergency kill switch and i do not have a cue how to reset it. i am in clyde NC can anyone tell me how to reset it? thanks x-count
Lift the hood, follow the cable and with your hand move it back forward. There is no spring so pushing the cable won’t help
 

pevrs114

Active member
188
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28
Location
Monroe, NC
I need some help on my 925 a2, my son in law pulled the emergency kill switch and i do not have a cue how to reset it. i am in clyde NC can anyone tell me how to reset it? thanks x-count
I may have mentioned this before, but the guy who runs the army/navy store in Clyde is a member here. He might be a good resource for you to get to know, and he's always got some cool surplus, too!
 

Mullaney

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Location
Charlotte NC
Well, I completely missed this thread before. I am in Winterville, NC with a m998.

Vince
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Hi Vince,

Welcome to the Outfit! I had no idea where Winterville is/was, so I went and poked the web and found it close to Greenville NC. Sorry you are so close to Raleigh. Not much of anything comes out of there. Just taxes and legislation that isn't very useful. :-(

If you get a chance to post up some pictures of your new-to-you HMMWV create yourself a new thread. That will get you some likes and get the conversations rolling. Guessing that you found the TM's (Technical Manuals) for your truck? If not, they will help with trouble shooting, part numbers, and what kind of oil and grease to use...


Again, welcome to the group.

Tim Mullaney
 

gobsmacked

New member
21
2
3
Location
bellevue mi
I may have mentioned this before, but the guy who runs the army/navy store in Clyde is a member here. He might be a good resource for you to get to know, and he's always got some cool surplus, too!
Lift the hood, follow the cable and with your hand move it back forward. There is no spring so pushing the cable won’t help
wheelspinner, i tried that, there seems to be a solenoid, that is pushing it, and will not reset, am still lost 925a2
 

gobsmacked

New member
21
2
3
Location
bellevue mi
Lift the hood, follow the cable and with your hand move it back forward. There is no spring so pushing the cable won’t help
I tried doing what you said. but there a solenoid, that seems to hold the cable, and doesn't reset. i can hold it and it steps right up and runs great. any ideals?????
 

ncfirefighter140

FiremanPhil
Steel Soldiers Supporter
59
14
8
Location
Central North Carolina
Hello everyone it's great to see the North Carolina page taking off. If any of y'all know other people in NC with Old Military Trucks or Equipment as them to join. Let's continue to grow our page!!

Sent from my SM-F926U using Tapatalk
 
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