M936A2 boom lift cyl hose replacement

[charlesmann]

Has anyone changed out the 2 hoses for the left hand boom lift cylinder (driver side when in the stowed position)? If so, what the hell tools did you use? i cant for the life of me get the return (short) hose off the dang NPT 90. i went to the snap on guy for the 1 3/8" and 1 1/2" crows feet, and applied heat, applied some beat with an air hammer to the 90, and that thing is seized in place i guess. I started cutting the swedge so i can get to it with a 1 3/8" socket, but as usual, my battery operated saw-zall battery must be taking a crap and a corded full size is to big to get in there with the lift cylinder installed. I wonder what the designer of that set up was thinking, if he was thinking in the first place, half JIC, half pipe thread. I would love to kick him in his berries every hour on the hour for a day.

 

[simp5782]

Has anyone changed out the 2 hoses for the left hand boom lift cylinder (driver side when in the stowed position)? If so, what the hell tools did you use? i cant for the life of me get the return (short) hose off the dang NPT 90. i went to the snap on guy for the 1 3/8" and 1 1/2" crows feet, and applied heat, applied some beat with an air hammer to the 90, and that thing is seized in place i guess. I started cutting the swedge so i can get to it with a 1 3/8" socket, but as usual, my battery operated saw-zall battery must be taking a crap and a corded full size is to big to get in there with the lift cylinder installed. I wonder what the designer of that set up was thinking, if he was thinking in the first place, half JIC, half pipe thread. I would love to kick him in his berries every hour on the hour for a day.

These at this point?

Get the boom up and out of your way. If you have a tree near by pull up to it. Rig your chain up as high as you can go with your snatch block. Run your cable from the front winch straight up up the block then back to the boom. Put the crowd out a little and hook your chain there... rig the lift lever open on the panel and use your winch to pull the boom up.. this works. I've done it a few times.. it gains you a little more access.

If you have a high strong limb you can get to and chain the block to then do that instead

 

[Mullaney]

Has anyone changed out the 2 hoses for the left hand boom lift cylinder (driver side when in the stowed position)? If so, what the hell tools did you use? i cant for the life of me get the return (short) hose off the dang NPT 90. i went to the snap on guy for the 1 3/8" and 1 1/2" crows feet, and applied heat, applied some beat with an air hammer to the 90, and that thing is seized in place i guess. I started cutting the swedge so i can get to it with a 1 3/8" socket, but as usual, my battery operated saw-zall battery must be taking a crap and a corded full size is to big to get in there with the lift cylinder installed. I wonder what the designer of that set up was thinking, if he was thinking in the first place, half JIC, half pipe thread. I would love to kick him in his berries every hour on the hour for a day.

.
Honest to goodness, I just can't quite understand how these fittings corrode. They aren't spastic, odd or weird. I got after mine with my normal "angle wrenches". About a third shorter than a regular wrench with a 30° and a 60° on the other end. I got nowhere. Huff and Puff and grunt and nothing. Walked back into the building and got a pair of combination wrenches. I didn't have enough "umph" to turn the fittings. Soaked it overnight with plain old WD40.

Next day, I brought a second set of hands to hold the steel pipe fitting and I used a second combination - so my lever length was about 3 feet. Fitting popped loose. There is no reason why it should have been that tight. There were folks who worked on the hydraulic shop I worked in though that used LocTite. No reason other than vibration... We might find that the Army may have specified the use of LocTite in the assembly of these cranes...

 

[simp5782]

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Honest to goodness, I just can't quite understand how these fittings corrode. They aren't spastic, odd or weird. I got after mine with my normal "angle wrenches". About a third shorter than a regular wrench with a 30° and a 60° on the other end. I got nowhere. Huff and Puff and grunt and nothing. Walked back into the building and got a pair of combination wrenches. I didn't have enough "umph" to turn the fittings. Soaked it overnight with plain old WD40.

Next day, I brought a second set of hands to hold the steel pipe fitting and I used a second combination - so my lever length was about 3 feet. Fitting popped loose. There is no reason why it should have been that tight. There were folks who worked on the hydraulic shop I worked in though that used LocTite. No reason other than vibration... We might find that the Army may have specified the use of LocTite in the assembly of these cranes...

I remember cutting some at one point and welding A 3/4" extension to them and using the impact on it to remove one. I

 

[charlesmann]

These at this point?

Get the boom up and out of your way. If you have a tree near by pull up to it. Rig your chain up as high as you can go with your snatch block. Run your cable from the front winch straight up up the block then back to the boom. Put the crowd out a little and hook your chain there... rig the lift lever open on the panel and use your winch to pull the boom up.. this works. I've done it a few times.. it gains you a little more access.

If you have a high strong limb you can get to and chain the block to then do that instead

Yes, those hoses/that cylinder. I have the boom as high as the stowage support legs will allow for. I don't have any trees tall enough, or strong enough to even trust supporting the weight, plus i have drained all the fluid in the tank, and have 1 of the cylinder lines off, but that dang short hose just will not come off. I have already gotten to far into the swedge to go back now, plus it was leaking already, which was the reason for replacement. I am about to the point of cutting the 90 off, taking out the reducer bushing going into the street T, and when the new line made, make it long enough and with a damn JIC on a 90 and get the NPT to JIC fitting

 

[charlesmann]

.
Honest to goodness, I just can't quite understand how these fittings corrode. They aren't spastic, odd or weird. I got after mine with my normal "angle wrenches". About a third shorter than a regular wrench with a 30° and a 60° on the other end. I got nowhere. Huff and Puff and grunt and nothing. Walked back into the building and got a pair of combination wrenches. I didn't have enough "umph" to turn the fittings. Soaked it overnight with plain old WD40.

Next day, I brought a second set of hands to hold the steel pipe fitting and I used a second combination - so my lever length was about 3 feet. Fitting popped loose. There is no reason why it should have been that tight. There were folks who worked on the hydraulic shop I worked in though that used LocTite. No reason other than vibration... We might find that the Army may have specified the use of LocTite in the assembly of these cranes...

I was using a trucker's chain binder bar on my ratchet and all i did was spread the crows foot enough for it slip the flats and go to the next flats. if my attempt with the sawzall fails here in a few, i will put a bag and rag over the other 2 exposed fittings and lines, and get the 4" grinder with a cut off wheel and cut the 90 off and use the 1 13/16" socket to get hopefully get the reducer bushing out

 

[simp5782]

Yes, those hoses/that cylinder. I have the boom as high as the stowage support legs will allow for. I don't have any trees tall enough, or strong enough to even trust supporting the weight, plus i have drained all the fluid in the tank, and have 1 of the cylinder lines off, but that dang short hose just will not come off. I have already gotten to far into the swedge to go back now, plus it was leaking already, which was the reason for replacement. I am about to the point of cutting the 90 off, taking out the reducer bushing going into the street T, and when the new line made, make it long enough and with a damn JIC on a 90 and get the NPT to JIC fitting

I always make all lines with 3/4" pipe on each end and buy fittings to get me what I need need get to so in the event I need to swap a line say from winch motor to the boom cylinder then I can sacrifice it and will interchange.

 

[Mullaney]

I was using a trucker's chain binder bar on my ratchet and all i did was spread the crows foot enough for it slip the flats and go to the next flats. if my attempt with the sawzall fails here in a few, i will put a bag and rag over the other 2 exposed fittings and lines, and get the 4" grinder with a cut off wheel and cut the 90 off and use the 1 13/16" socket to get hopefully get the reducer bushing out

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You might try tapping with a hammer as far around the nut as you can reach, then go for it again with a wrench. If you have a spare set of hands - maybe smack the wrench with a hammer. (like you would do with an impact socket that just won't quite budge a lug nut)

 

[charlesmann]

I always make all lines with 3/4" pipe on each end and buy fittings to get me what I need need get to so in the event I need to swap a line say from winch motor to the boom cylinder then I can sacrifice it and will interchange.

ALL NPT fittings/lines will eventually be changed to a flared JIC. I HATE pipe fittings and with they didn't exist in the hydraulic world. For the past 20 years, its either been AN or MS fittings, operating at the 3000+ psi and very, very little issue.

 

[simp5782]

ALL NPT fittings/lines will eventually be changed to a flared JIC. I HATE pipe fittings and with they didn't exist in the hydraulic world. For the past 20 years, its either been AN or MS fittings, operating at the 3000+ psi and very, very little issue.

Better npt than inverter flare.

 

[charlesmann]

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You might try tapping with a hammer as far around the nut as you can reach, then go for it again with a wrench. If you have a spare set of hands - maybe smack the wrench with a hammer. (like you would do with an impact socket that just won't quite budge a lug nut)

If an air hammer didn't do it, id be highly skeptical of a hand hammer working any better. No extra hands, i end up running solo for 99.9% of the operations/maint and when it comes to my wife, i get as much help as boar does with tits, and my neighbor, well, lets just say, a little more help, but not the best at mechanical inclination.

 

[Mullaney]

If an air hammer didn't do it, id be highly skeptical of a hand hammer working any better. No extra hands, i end up running solo for 99.9% of the operations/maint and when it comes to my wife, i get as much help as boar does with tits, and my neighbor, well, lets just say, a little more help, but not the best at mechanical inclination.

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Sad to say that I understand.
The ones with and without tits...

 

[charlesmann]

Better npt than inverter flare.

Very true sir. If i have to, i'll go MS and or AN. It might cost more, unless i come across bin of extra, never gonna be used, fittings at work

 

[simp5782]

I

Very true sir. If i have to, i'll go MS and or AN. It might cost more, unless i come across bin of extra, never gonna be used, fittings at work

I use the NPT on the hoses to get me to fittings for the JIC so it can interchange with other fittings say if some are 10s and others are 12s but the npt to JIC fittings are always 3/4 female pipe to be able to interchange

 

[charlesmann]

I
I use the NPT on the hoses to get me to fittings for the JIC so it can interchange with other fittings say if some are 10s and others are 12s but the npt to JIC fittings are always 3/4 female pipe to be able to interchange

I see what you are saying. In this case, stay NPT at the hose, change out the reducer bushing to a NPT to JIC, and get a NPT 90 with a -10 swivel jic. doing it that way should keep the length the same. I was just figuring since there was a jic at the cyl, might as well change the 90 and reducer out for a jic as well. I will be replacing the other line since I'm already in there

 

[simp5782]

I see what you are saying. In this case, stay NPT at the hose, change out the reducer bushing to a NPT to JIC, and get a NPT 90 with a -10 swivel jic. doing it that way should keep the length the same. I was just figuring since there was a jic at the cyl, might as well change the 90 and reducer out for a jic as well. I will be replacing the other line since I'm already in there

Yes because even if you need a hose in a pinch most places napa. O'Reilly parker etc will always have pipe connectors to crimp on not always JIC or 90s anyways.

I always keep 2 spare reusable 3/4 hose to 3/4 pipe fittings with me and 10ft of 3/4in hose so I can fix a hose on the spot with a new one over having to go to town.

Military used reusable fittings on most cotton jacket air lines but not so much on the larger hydraulic stuff.

 

[charlesmann]

So, after disconnecting the cyl from the boom, some new curse words and after a modified bush and new swivel 90 instal, i have the 2 new hoses installed. I over shot the cyl pin hole and now gotta try find a way to get the cyl rod pushed down enough to get the pin in it.
I do have a question on servicing though. If the tank has a 100 gal capacity, then why with it filled to 70% of cap, does it burp/purge out the fill neck when sticking in or booming down rapidly? Can the tank just not take the amount of fluid returning at a fast rate?
I thought initially when i replaced the fluid a yr ago, that at 100gal, it was over serviced and was puking out, but after draining 68 gal, and adding 2gal of lucas hyd oil stabilizer and leak protector, iv got 30% more fluid to add, yet its already puking out.

I did rmv the filter, cleans, insp and reinstalled it, so that shouldnt be causing it, or i wouldnt think it would be the cause.

 

[Mullaney]

So, after disconnecting the cyl from the boom, some new curse words and after a modified bush and new swivel 90 instal, i have the 2 new hoses installed. I over shot the cyl pin hole and now gotta try find a way to get the cyl rod pushed down enough to get the pin in it.
I do have a question on servicing though. If the tank has a 100 gal capacity, then why with it filled to 70% of cap, does it burp/purge out the fill neck when sticking in or booming down rapidly? Can the tank just not take the amount of fluid returning at a fast rate?
I thought initially when i replaced the fluid a yr ago, that at 100gal, it was over serviced and was puking out, but after draining 68 gal, and adding 2gal of lucas hyd oil stabilizer and leak protector, iv got 30% more fluid to add, yet its already puking out.

I did rmv the filter, cleans, insp and reinstalled it, so that shouldnt be causing it, or i wouldnt think it would be the cause.

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According to the Lubrication Order, LO9-2320-272-12

Weekly, with boom in horizontal position, remove oil filler cap and gage from top of reservoir. If level is below full mark on gage, replenish to full mark. Every 12,000 miles (19,000 kilometers) or 12 months, whichever occurs first, remove pipe plug from drain valve, attach hose (furnished with vehicle), and drain oil into a container. Remove plug in bottom of reservoir to completely drain. Always install plug in drain valve after draining. Refill reservoir to full mark on oil level gage (approximately 100 gallons (378.5 liters)), operate crane several times to completely fill system check level.

There would be oil on top of the piston (boom down) and oil under the piston (boom up) - but in my mind - swapping cylinders shouldn't have caused to tank to overflow. That measurement of 100 gallons is with an empty system like it would have been at build time..

Wish I knew more or was smarter...

 

[simp5782]

I've never ran more 60 or 65 gallons in mine. Mine runs at idle all the time when operating. I would check the fluid temp after running it hard. I only use 10wt since i could get it by the drum for $200

 

[charlesmann]

@Mullaney i didnt swap cylinders, and the cyl that did get swapped before i got it, was on the tank side.

Going with the 100 gal with a completely empty system, then i did over svc the tank.

After putting everything back together properly, including the boom cyl pin and retaining bolt, i was running the system through all ranges of motion for 10 min or so to hopefully bleed all the air out of the lines and cyl, i did notice a smell that i havent smelled before. It def was a petroleum smell and could have been the lucas hyd additive, but uncertain.

I did, while i was in the hyd system, pull the crane winch motor to put the spare motor on so i could put new seals on my original motor, just to find out the spare was a leaking sob too.

Ill contact parker and verify the p/n of seals and order 2 of everything and while im down for post surgery recovery starting mon after i get out of the OR, ill have several weeks before ill be climbing on the tck, which will give me time to get the seals in and have them replaced by the local parker people in waco.

After that, ill work on figuring out the damn brake dragging issue.