What is the name of panel of rotary switches that direct air to the cab, suspension?

[Reworked LMTV]

I'm having issues with the panel of rotary switches that direct air to the cab, suspension mounted on the passenger side of the truck. I need to search for info. Anyone know the official name of this thing?

 

[simp5782]

This thing?

hydraulic control valve body. NSN 4730-01-457-8479 Manifold Hydraulic System Access.

 

[Reworked LMTV]

This thing?

hydraulic control valve body. NSN 4730-01-457-8479 Manifold Hydraulic System Access.

Yes, thank you. Can you rebuild these? Mine seems to be leaking air out inappropriately.

 

[simp5782]

Yes, thank you. Can you rebuild these? Mine seems to be leaking air out inappropriately.

Im sure you can. You can take it your local parker store abd they can send it to their rebuild facility. Not sure of the cost. Their facility in blytheville, ar does my walking floor hydraulic cylinder rebuilds.

Or any hydraulic cylinder repair place can rebuild it i am sure. Suprman has units gor sale though if the cost of rebuild is high

Sent from my SM-G935P using Tapatalk

 

[tennmogger]

If the problem is air leaking from the hydraulic control valve body that might be good news. I think there is only one valve on the hydraulic control that has air and that's the one you push and hold to activate the air to hydraulic pump up behind the hydraulic control. All the other circuits are hydraulic. If the air leaks out before the pump gets air then there will be no hydraulic power.

What is the nature of your failure? Nothing works?

 

[Suprman]

There are 2 air circuits. One for the cab airbags and one when you press the hydraulic actuation valve button it send air to the air hyd pump. This control has a check valve behind it with o rings. It will unscrew and you can take a look at it. There are 2 different styles. I have the replacement valve and check that goes in behind it if yours is just bad.

 

[tennmogger]

Oh, forgot that one! Thanks Will. I assumed the OP was concerned with cab lift, suspension (kneeling circuit) etc. More info needed.

 

[firefinder]

I had a leak in the switch manifold. Turned out to be the push button switch for the cab air bags (or air springs as listed in the Operator's Manual). All of the o-rings were available locally. Once the o-rings were replaced, everything worked fine. Photo of the switch I rebuilt:



Here is a related prior thread with rebuild kit info and photos of other components:

https://www.steelsoldiers.com/showthread.php?155350-Coolant-Took-A-Vacation/page4

 

[Reworked LMTV]

I had a leak in the switch manifold. Turned out to be the push button switch for the cab air bags (or air springs as listed in the Operator's Manual). All of the o-rings were available locally. Once the o-rings were replaced, everything worked fine. Photo of the switch I rebuilt:

View attachment 709561

Here is a related prior thread with rebuild kit info and photos of other components:

https://www.steelsoldiers.com/showthread.php?155350-Coolant-Took-A-Vacation/page4

Thanks Firefinder! I love rebuilding things....well...most things ; )

 

[Reworked LMTV]

If the problem is air leaking from the hydraulic control valve body that might be good news. I think there is only one valve on the hydraulic control that has air and that's the one you push and hold to activate the air to hydraulic pump up behind the hydraulic control. All the other circuits are hydraulic. If the air leaks out before the pump gets air then there will be no hydraulic power.

What is the nature of your failure? Nothing works?

Yes, nothing works. Air now rushes out from the lower rear of the manifold if right lower control is not pushed in and turned. Cab is stuck slightly open (probably air from hydraulic pump rebuild? ). I can hear the pump trying to work with minimal air, then a valve kicks in and shuts down the air to the pump. Manual pump now will not working either.

I think there are 2 issues with my air / hydraulic system.

 

[Suprman]

Air coming out the back of the manifold is usually the check valve behind the control knob. Could just be the o rings on it though. If the air is escaping and not making it to the air hyd pump then you wont get much hyd pressure. If the manual pump dosnt work then you are probably low on fluid or have air pockets in the system.

 

[coachgeo]

Yes, nothing works. Air now rushes out from the lower rear of the manifold if right lower control is not pushed in and turned. Cab is stuck slightly open (probably air from hydraulic pump rebuild? ). I can hear the pump trying to work with minimal air, then a valve kicks in and shuts down the air to the pump. Manual pump now will not working either. ..I think there are 2 issues with my air / hydraulic system.

did this all start after rebuilding manual cab lift pump? And these issues where not there before? If so that might change things when considering diagnosis

 

[Guyfang]

In the end, it's sometimes good to know the "rest of the story."

 

[Reworked LMTV]

did this all start after rebuilding manual cab lift pump? And these issues where not there before? If so that might change things when considering diagnosis

Well, it first started with the blowing of hydraulic oil out of the air / hydraulic pump. I had noticed that this pump was getting slower and struggled to lift the cab. I checked the manual pump, and at the time of the air / hydraulic rebuild, it worked fine. Are the cab hydraulics PowerPacker like the air suspension?

 

[Suprman]

Ok so you are low on fluid because it all blew out the breather. Put fluid in the hyd pump reservoir and work the hand pump to get the air out.

 

[Reworked LMTV]

Ok so you are low on fluid because it all blew out the breather. Put fluid in the hyd pump reservoir and work the hand pump to get the air out.

I already refilled it and the manual pump will not move it. I assume I just crack a line to get the air out?

 

[coachgeo]

I already refilled it and the manual pump will not move it. I assume I just crack a line to get the air out?

suspect it works like bleeding brakes... crack line... pull pump arm down and keep it down.. re-tighten what you cracked..... lift handle back up....... Repeat.

 

[aleigh]

When some of my valves went bad due to corrosion I had the same symptoms OP describes. It was quasi sporadic. The pump was working against a check valve or whatever that wouldn't open - it was actually on the fluid release side (past the cylinder) in my case. To get the cab down I had to crack a line and let it bleed out (since it couldn't return to the reservoir). When I took the entire manifold apart it had corrosion everywhere so if he's having these problems my advice is pull the whole thing and pull all the valves or you might just be back at it in another six months when the next one goes.

The stock fluid has no corrosion protective properties - replace with another hydro fluid that does (what I did anyways).

https://www.flickr.com/photos/adventioneering/albums/72157669897327435

 

[Reworked LMTV]

Ok so you are low on fluid because it all blew out the breather. Put fluid in the hyd pump reservoir and work the hand pump to get the air out.

Thank you for your input. You are an asset to this forum : )

 

[Reworked LMTV]

When some of my valves went bad due to corrosion I had the same symptoms OP describes. It was quasi sporadic. The pump was working against a check valve or whatever that wouldn't open - it was actually on the fluid release side (past the cylinder) in my case. To get the cab down I had to crack a line and let it bleed out (since it couldn't return to the reservoir). When I took the entire manifold apart it had corrosion everywhere so if he's having these problems my advice is pull the whole thing and pull all the valves or you might just be back at it in another six months when the next one goes.

The stock fluid has no corrosion protective properties - replace with another hydro fluid that does (what I did anyways).

https://www.flickr.com/photos/adventioneering/albums/72157669897327435

Good photos at flicker. Looks like you did fuel lines too. I need to do that.

There was all sorts of gunk in the hydraulic fluid tank. I assume it is elsewhere. My symptoms sound like the ones you had. The pump seems to be fighting a valve. I'd like to flush the who system. Hard to understand a Mil truck would have no corrosion control in the hydro fluid.