Cab and spare hydraulics problems M1078 LMTV

[aleigh]

My TM -24P is showing Parker. CAGE 09990.

In any event I plan to take the entire mess out to our industrial hydro place tomorrow and dump it on their counter, they can sort it out.

Edit- I see what is going on. There are two hydro manifold assemblies for the LMTV. They are handled separately in the -24P and the 20-4. One of them is made out of Parker things and the other one is made out of SPX things. I have the former.

 

[Fireball1]

aleigh:
Found that the check balls in the cab cylinder was sticking. Removed and discarded. The only reason they are there is in case a hose breaks so the cab locks in the up position. It apparently has to have some residual pressure to keep the ball un seated when the cab is lowered. I checked with a Stewart and Stevenson rep and he really didn't tell much.
As for TMs A full set can be found on this link http://www.steelsoldiers.com/showthread.php?118919-M1078-TM-s . The schematic is found on page 939 of TM 9-2320-365-20-4. The manuals can be saved from the above link.
We have removed the spare tire carrier an cylinders for suspension compression. We are building a wildland fire truck for our department with ours.
Thanks to all who have replied for our problem.

 

[coachgeo]

aleigh:
Found that the check balls in the cab cylinder was sticking. Removed and discarded. The only reason they are there is in case a hose breaks so the cab locks in the up position. ....

Is not the same as saying.... so it wont fall down and crush you to death when working under it ...? IMHO If ya'll choose to keep it that way at the firehouse it should be stenciled in plain site on rear or cab and/or by the hydro control box that it could fall. Not just for ya'll but for anyone 15yrs down the road who buys it in county auction after it is retired.

 

[Reworked LMTV]

I have this same problem on all my circuits, leading me to believe it's something in the manifold. Cab is stuck up right now. I've got the manifold off and I'm basically at the point of rebuilding it, I had leaky valves anyways. Did you ever get into your manifold and learn more about the problem?

Where did you find the hydro schematic? I'd like to see it. I have been backwards and forwards over the TMs and haven't run across it, or else I'm blind.

Where did you find your parts to rebuild it ? Thanks!

 

[aleigh]

Is not the same as saying.... so it wont fall down and crush you to death when working under it ...? IMHO If ya'll choose to keep it that way at the firehouse it should be stenciled in plain site on rear or cab and/or by the hydro control box that it could fall. Not just for ya'll but for anyone 15yrs down the road who buys it in county auction after it is retired.

I meant I discarded and replaced the check valves - not that I made a death trap. Sorry for the ambiguity, I could have been clearer.

 

[aleigh]

Where did you find your parts to rebuild it ? Thanks!

I walked into the local hydro shop in Seattle, on the Ballard docks by the crab boats. Forget the name now. They scratched their heads for a long time, eventually ended up calling the manufacturer. The trick is apparently that the part #s are for military contract parts, not off the shelf parts, but the valves are from a commercial series (now out of date) so it's about cross-referencing the military part #s to corresponding military part #s. For the price though see if you can find a NOS manifold. I was able to get one a while later for a good price, complete with all the valves and everything.

I don't remember if I mentioned this on the thread or not - apologies if I did - but apparently rust is a problem if the fluid is not changed regularly. Water gets in there and surprise - rusts the things. Eventually I changed out to a different hydro fluid used on airplanes which has anti-corrosive additives so hopefully in the long term that'll reduce/eliminate the problem.

 

[coachgeo]

... apparently rust is a problem if the fluid is not changed regularly. Water gets in there and surprise - rusts the things. Eventually I changed out to a different hydro fluid used on airplanes which has anti-corrosive additives so hopefully in the long term that'll reduce/eliminate the problem.

hmmm. interesting thanks. Not sure the temps hydraulic oil vaporizes. but Im sure it is higher than water... so you could probably drain your oil occasionally into a dedicated pot and put it on your turkey fryer burner, camp stove or?? to boil out the water. Once it is cool...... put it back in.

Back in the day when did Veg. Oil fuels.. we did a spoon test. Take a big spoon of it and heat with lighter. See how many bubbles you get or not. Will at least tell you if there is water in there or not. Another was a hot pan test. same idea. Put a measured amount Y (same all the time) and watch for bubbles at X temp setting.

Like the idea of airplane hydraulic fluid. Where would one get that? The newer more expensive tractor hydraulic fluid is probably close to same thing. More synthetic... which may mean it should be less hydroscopic (AKA- something that attracts water from atmosphere etc.)

 

[aleigh]

I mentioned this on another thread but since then I had a hydro guy look over the truck and he pointed out the filters on the tanks are desiccant traps to dry the air going into the tank. The desiccant wears out and needs to be replaced regularly - I doubt many of us are doing that. I certainly wasn't. It's a standard fitting, so the service life will be dependent on whatever you replace it with.

 

[tennmogger]

Aleigh, are you referring to the big air dryer near the 'wet' tank? If not, which filters are you meaning? For the big air dryer, the desiccant packs and coalescing filter kit is readily available (like 'minor kit' part number R60 at Finditparts) and not much work to change out. But, be sure your air dryer is cycling properly too. It should spit out water, and any oil accumulated, on a regular basis. You can hear it do the purge during driving, or find evidence on the ground under the dryer if the truck is running, not moving, and air system comes up to pressure and cycles the compressor governor.

 

[aleigh]

Aleigh, are you referring to the big air dryer near the 'wet' tank? If not, which filters are you meaning? For the big air dryer, the desiccant packs and coalescing filter kit is readily available (like 'minor kit' part number R60 at Finditparts) and not much work to change out. But, be sure your air dryer is cycling properly too. It should spit out water, and any oil accumulated, on a regular basis. You can hear it do the purge during driving, or find evidence on the ground under the dryer if the truck is running, not moving, and air system comes up to pressure and cycles the compressor governor.

No, not that. And funny enough the air pump for the hydraulic pump feeds off the wet tank (AFAIK). No, on the air hydraulic power pack located under the chemical detector mount (integral with the reservoir for the cab lift/tire life/suspension hydraulic system components) is an air desiccant filter. It looks like a cone made out of brass beads. This vents the tank to the outside world. As I mentioned when the fluid level in the tank falls, outside air will be drawn into the tank to take up the difference. If the desiccant is used up, the air will be wet, leading to eventual problems.

It's also my conjecture it gets ruined if you blow fluid out it... And I also don't know if they are rain proof or not. Mine is uncovered come to think of it, I never re-installed the detector bracket.

 

[NDT]

No, not that. And funny enough the air pump for the hydraulic pump feeds off the wet tank (AFAIK). No, on the air hydraulic power pack located under the chemical detector mount (integral with the reservoir for the cab lift/tire life/suspension hydraulic system components) is an air desiccant filter. It looks like a cone made out of brass beads. This vents the tank to the outside world. As I mentioned when the fluid level in the tank falls, outside air will be drawn into the tank to take up the difference. If the desiccant is used up, the air will be wet, leading to eventual problems.

It's also my conjecture it gets ruined if you blow fluid out it... And I also don't know if they are rain proof or not. Mine is uncovered come to think of it, I never re-installed the detector bracket.

You have been told wrong, the part is a muffler and does nothing to dry air. Actually it admits rainwater which is how these systems get damaged. McMaster part 4450K2 if you need one.

 

[Awesomeness]

It's also my conjecture it gets ruined if you blow fluid out it...

Nah, it should essentially last forever unless you physically break it. It's essentially just a brass "sponge", so if fluid gets in it it will just drain back out over time.

 

[aleigh]

Thanks for correcting me - it is just what the guy told me. That said, I looked them up and might be worth retrofitting one. That's a good tip about the rain.

I do NOT want to have hydraulic problems ever again!

 

[Aernan]

I don't remember if I mentioned this on the thread or not - apologies if I did - but apparently rust is a problem if the fluid is not changed regularly. Water gets in there and surprise - rusts the things. Eventually I changed out to a different hydro fluid used on airplanes which has anti-corrosive additives so hopefully in the long term that'll reduce/eliminate the problem.

what hydro fluid is that?

 

[coachgeo]

hydaulic "oil" is a light oil..... and like most any light oil it is liable to be hydroscopic (substance tending to absorb moisture from the air). There is a few thing on the market like water separate filters.

 

[Ohiobenz]

I think this is about the best the TM has. This is probably too small to read, but take a look starting at page 1,205 of TM 9-2320-365-20-3

View attachment 629205

 

[mauinate]

Anyone know what pressure the pump can put out?

 

[Ronmar]

Anyone know what pressure the pump can put out?

 

[MatthewWBailey]

New here. My spare tire cylinder seems jammed. Air pump struggles to push it at all. Tires in the up position. Even the manual pump can't move it. Cab lift/lower works fine. It's 2 degrees here so maybe I've got frozen water/fluid or something in the cylinder?

Has anyone ever tried to swap out the tire lift hydraulics for an electric Jack screw?

 

[Suprman]

Sounds like a clogged restrictor