Newbie Alert! New LMTV in DFW

[MatthewWBailey]

Small victories- found the reservoir and dipstick. It’s bone dry. I plan to head up to the auto parts store later tonight and pick some up. I read in another post that it takes 27 gallons, does that sound right?

Another basic question, where do I refill it? Can anyone point me towards a schematic or FAQ?

Not 27 gallons. That's for a winch system. AOP is quarts. I topped mine off after removing a cylinders worth and it was 1-1/2quarts added.

 

[Third From Texas]

Small victories- found the reservoir and dipstick. It’s bone dry. I plan to head up to the auto parts store later tonight and pick some up. I read in another post that it takes 27 gallons, does that sound right?

Another basic question, where do I refill it? Can anyone point me towards a schematic or FAQ?

No, not on the standard trucks. The 27 gal may be a winch truck with it's giant reservoir). A gallon should do you (but I usually pick up a spare to carry). And a ground pan to catch any discharge (a small kiddie pool was the cheapest I found).

If there is a leak. what you add will often blast right out.

But yeah, super common to find a dry hole. People unfamiliar with hydraulics tend to keep pumping on them in hopes it will magically work. LOL

 

[GeneralDisorder]

You fill through the dipstick hole. Get one gallon that will be more than sufficient.

 

[hike]

Does the AOP use special hydraulic oil, like aviation hydraulic?

 

[GeneralDisorder]

Does the AOP use special hydraulic oil, like aviation hydraulic?

Yes. MIL-PRF-5606H.

https://shop.boeing.com/aviation-supply/p/756-1QT=2U

 

[chucky]

And above all else, if/when you get the cab up...block it up with a 4x4.

@chucky has a good story to tell about the fluid dumping out in an instant when he had the cab up to work on the system. He got to use his head to hold the 4000# cab up until he neighbors and rescue arrived to take some of the load off his crushed skull.

Fortunately, he was already a little different before so he recovered with no noticeable change...

Ye im perfectly fine now ! I went out to eat just the other day !

Just click on the WATCH ON YOUTUBE line

 

[IronhorseTX]

Ok, filled both reservoirs and nada. There aren’t any leaks, and there isn’t any pressure build up either when I try to use the manual pump. The air over hydraulics is chugging as it was before but nothing is moving.

 

[Ronmar]

well if both pumps have fluid yet neither pump loads up, i suspect the valve probably has a bad seal and is leaking from pressure side to return side…

you remove the handle and there is a nut to unscrew the core to access the seals…

 

[Primussucks]

Hi [mention]IronhorseTX [/mention]
Also a new A1R owner in DF/W. M1078

I’m two months in and have learned a ton. The members here have a tremendous amount of knowledge and are extremely patient with the newbies.

I’m in the process of converting into our new overland rig as well.

Going through mechanical stuff right now. I think I’ve gathered everything for ecohubs, seals, bearing and brake service. I hope to start in the next two weeks.

Where in df/w are you?

 

[IronhorseTX]

@Primussucks - pleasure to meet you! I love that there are some folks in the area. I just picked up this M1085A1R about a week ago and am working towards a 4 yr expedition truck build. I gave myself 2 yrs for the chassis prep and 2 for the habitat - let’s see if I actually stick to it. I’m in far north east Dallas area (Sachse/Wylie).

Ecohubs are on the list but I’m stuck trying to work through little battles, like accessing the engine.

 

[GeneralDisorder]

Ok, filled both reservoirs and nada. There aren’t any leaks, and there isn’t any pressure build up either when I try to use the manual pump. The air over hydraulics is chugging as it was before but nothing is moving.

The air operated pump probably needs to be rebuilt - there's a yellowish colored seal inside them that disintegrates into a whole bunch of little yellow bits and then clogs up everything. They aren't terribly hard to rebuild but it does require some patience and careful attention to detail.

 

[IronhorseTX]

@GeneralDisorder - when I bought the truck the previous owner had the pump recently resealed. Would that have repaired the part you’re referring to?

 

[GeneralDisorder]

@GeneralDisorder - when I bought the truck the previous owner had the pump recently resealed. Would that have repaired the part you’re referring to?

Not sure exactly what they mean by that. The overhaul/seal kit is about $200 from Parker. Did it work before or after they did this "reseal"?

 

[Ronmar]

step 1 establish you have a source or pressurized oil. Even if the AOP is shot, and they often are, the hand pump should work, they are pretty robust units, but also easy to test. Remove the line from the lower port on the hand pump(pretty sure that is the output) cap/block its output and see if you can pump the hand pump. If you cannot(handle hydraulically locked) then that pump is fine and a valid source.

Now that you know If its full of fluid, and not pumping fluid out thru a leak somewhere when you work the lever, then you are sending fluid somewhere. The only way it wouldn’t work is if the output check on the AOP was leaking back, the control valve is leaking across from pressure to return, or all the cylinders you are trying to move have blown piston seals…

a common leak point are the seals within the control valve assembly…

 

[GeneralDisorder]

Even if the AOP is shot, the hand pump should work, they are pretty robust units… the only way it wouldn’t is if the output check on the AOP was leaking back, or the control valve is leaking across from pressure to return…

Ron is correct - have you pumped it A LOT? Like for 10+ minutes as fast as you can manage? It can take a WHILE if you don't have have the AOP working and air has got in the system from it being run dry.

 

[IronhorseTX]

Sorry, let me clarify. The hydraulics didn’t work prior and the previous owner bought a refurbished pump that was resealed and installed plus he replaced the latch seals too.

I definitely didn’t pump it for 10 mins. I’ll get back out there later this after when it cools off outside and start cranking away. Thank you for the guidance!

 

[IronhorseTX]

Ok, pumped that sucker for 20 mins. Checked the reservoirs each time for fluid and no dice. There is no resistance on the lever and no different result when I use the air over hydraulics. Time to remove the line and check the pump…

 

[Third From Texas]

Ok, pumped that sucker for 20 mins. Checked the reservoirs each time for fluid and no dice. There is no resistance on the lever and no different result when I use the air over hydraulics. Time to remove the line and check the pump…

So no fluid in the reservoirs?

Sounds like air in the line to me.

Fill, cap, pump
Fill, cap, pump
Fill, cap, pump

Focus on the manual pump first. You can even leave the cap off and hand pump. Watch the fluid level drop, top it off. If it starts puking oil as the fill hole, then cap it and pump some more. Uncap it and add oil. Rise/repeat (a LOT).

Until pressure is felt. You need to bleed the air out of the system.


One pump might be bad. But both at the same time is highly unlikely.
It sounds like it's just air in the lines....

 

[Ronmar]

Ok, pumped that sucker for 20 mins. Checked the reservoirs each time for fluid and no dice. There is no resistance on the lever and no different result when I use the air over hydraulics. Time to remove the line and check the pump…

If the hand pump pumps fluid out its pressure port, it shouldn’t take all that long to prime/fill lines and start building pressure/doing work. The hand pump is sealed/has no vent port. As the hand pump pushes out fluid, it pulls a vacuum in the reservoir and should draw fluid in from the AOP reservoir So both need to have fluid in them.

It is a .25 cu/in single acting pump. The lines are 1/4” so every 5” of line is .25cu/in in volume. A 6 foot line should fill in 15 pump strokes… there is perhaps 12’ of line between the hand pump and the cab lift cylinder, so 30 pump strokes? If everything was working normally and If the fluid is pushing air ahead of it, it should start building pressure as it compresses the air and you should feel resistance on the lever. You can loosen the fitting at the base of the cylinder and push all the air out of the line to speed the process, but the air will push past the piston seal to the rod end side eventually and find its way back to the reservoir.

I suspect you will find the hand pump is fine, and you have a bad seal in the control valve… You can also test the AOP with that same hand pump output line removed. Both pump outputs are tied together in the control valve, and they have output check valves on each pump to allow the other pump to build pressure in the system. With the hand pump line disconnected and run into a container, if you operate the AOP it should pump fluid out that line…

unfortunately if it is the control valve, you are kind of stuck until you locate and replace the bad O-rings in the valve.

Since this truck is an unknown to you. You should probably first confirm that all the hoses are actually connected correctly. If the pump hoses are swapped at one end, the fluid would simply pump to the reservoir of the other pump and never build any pressure…

 

[Third From Texas]

Checked the reservoirs each time for fluid and no dice

Maybe I'm misunderstanding what he said, but if he's seeing no fluid in the reservoirs then that should point to air in the lines (and not fluid).
No fluid, no pressure, no worky.
Again, I'm assuming (which is bad) that "no dice" means no fluid in the tanks.


Lets say that the system is only 25% full (random number) when he got the truck.
The reservoirs would be dry.
He tops off the reservoirs, and pumps for 20 minutes.
Nothing has changed, nothing would. It would still be mostly air in the lines.
The system is only 30% full now.
He's seeing no oil leaks. Expected. There's no pressure. Air is still in the majority of the system.

You bring up a valid point about a possible hose misconnected (we know someone prior mucked with it).
But if his tanks are dry after topping them off, he shouldn't just move on to the next troubleshooting point, IMO.
To me, dry tanks after topping them off indicates the system took that fluid in.
It needs more fluid.
He needs to bleed the system until the tanks are full and any air is removed.
That's when he'll likely see things start to move and likely discover the leak if one exists (once the system is fully bled of all air and pressure can build).

Again, I may be misunderstanding what he meant.
But if he's seeing a dry hole in each tank, he's not bled the air and IMO he should keep at it before tearing apart the pumps, rerouting hoses, etc.

edit: I'd maybe even focus on the tire lift first (bypass the the stuff that's not right there to watch). If he can get that working, then flip it to cab lift and see what happens