New LMTV owner

[Ronmar]

Question. Has anyone ever hooked an air compressor up to your truck before, without the engine running? So, I have had the cab tilted fwd for over a week, been working on the engine area. Well, I made a quick disconnect air chuck an attached it to the front air supply. Because I wanted to lower the cab. Slowly the pressure started coming up on the tanks. But I started finding small air leaks. the fwd port air brake bladder is leaking air. there are some small black hoses that leak air, and the cab air ride has a small leak also. Is it because air tanks are filling up slower or do I have an actual concern hear?

You have leaks, fix them. Speed of fill makes no difference. You just couldn't hear them over the engine before

did you add air thru the front red glad-hand? If so, be careful, that also releases the park brakes, so chock the wheels…

 

[Joseph A.]

You have leaks, fix them. Speed of fill makes no difference. You just couldn't hear them over the engine before

did you add air thru the front red glad-hand? If so, be careful, that also releases the park brakes, so chock the wheels…

Did not use the red side. Wheel chocks are now on the list, thank you for that.

 

[Ronmar]

Did not use the red side. Wheel chocks are now on the list, thank you for that.

So where exactly did you connect the air to?

 

[Joseph A.]

So where exactly did you connect the air to?

I have it hooked up to the blue side.

 

[Reworked LMTV]

Question. Has anyone ever hooked an air compressor up to your truck before, without the engine running? So, I have had the cab tilted fwd for over a week, been working on the engine area. Well, I made a quick disconnect air chuck an attached it to the front air supply. Because I wanted to lower the cab. Slowly the pressure started coming up on the tanks. But I started finding small air leaks. the fwd port air brake bladder is leaking air. there are some small black hoses that leak air, and the cab air ride has a small leak also. Is it because air tanks are filling up slower or do I have an actual concern hear?

Wade into your rebuild of your truck slowly. Ask lots of questions. The diaphragms in the air brake cans can be replaced, BUT doing them without working knowledge can kill you. The springs inside are so powerful they can easily crush a face. Better to replace. There are miles of air lines on these trucks. The lines get brittle, especially when the plastic is exposed to compressed air oil. Replace whenever possible. Label your lines as you go. Label the valves too. Use industrial dymo tape or a paint pen NOT perm markers. Markers fade. If you break down, those labels will be a blessing. Use soapy water to find leaks. I used of few field replaceable brass connectors when I rebuilt mine. I have used a smoke machine on some lines too. The cab air ride bags leak at lot. They wear at their fold at the rubber bladder at the bottom. Replace with Power Pack components or new modded version.

Make a list of priorities. Start with safety items. Check tire codes for age of tires. Old ones can put you in a ditch.

 

[Joseph A.]

Wade into your rebuild of your truck slowly. Ask lots of questions. The diaphragms in the air brake cans can be replaced, BUT doing them without working knowledge can kill you. The springs inside are so powerful they can easily crush a face. Better to replace. There are miles of air lines on these trucks. The lines get brittle, especially when the plastic is exposed to compressed air oil. Replace whenever possible. Label your lines as you go. Label the valves too. Use industrial dymo tape or a paint pen NOT perm markers. Markers fade. If you break down, those labels will be a blessing. Use soapy water to find leaks. I used of few field replaceable brass connectors when I rebuilt mine. I have used a smoke machine on some lines too. The cab air ride bags leak at lot. They wear at their fold at the rubber bladder at the bottom. Replace with Power Pack components or new modded version.

Make a list of priorities. Start with safety items. Check tire codes for age of tires. Old ones can put you in a ditch.

Soapy water. Freaking genius! I’m working on things I can see, fixing what looks old (everything looks old). This truck is so cool but man was it neglected. And after yesterday, hearing the air leaks, it’s shined a light onto what I can’t see, or hear.
Thank you all

 

[Lostchain]

Question. Has anyone ever hooked an air compressor up to your truck before, without the engine running? So, I have had the cab tilted fwd for over a week, been working on the engine area. Well, I made a quick disconnect air chuck an attached it to the front air supply. Because I wanted to lower the cab. Slowly the pressure started coming up on the tanks. But I started finding small air leaks. the fwd port air brake bladder is leaking air. there are some small black hoses that leak air, and the cab air ride has a small leak also. Is it because air tanks are filling up slower or do I have an actual concern hear?

I don’t know a ton about the air system but I did this on my truck and you are supposed to connect to the red glad hand. That should fill the tanks quick but also will remove the parking brake. I could be wrong but I feel like your tanks filling up off the blue side would indicate failing check valves. My understanding is those are commonly corroded.

Hooking LMTV to shop air for CTIS troubleshooting

Hey all. Has anyone had experience hooking their LMTV to shop air so that they can troubleshoot air issues without the engine running? I tried hooking up to the front service gladhand, but the system didn’t take much air. I looked at the pneumatic schematic in the TM and I think maybe that’s...

steelsoldiers.com

 

[Joseph A.]

I don’t know a ton about the air system but I did this on my truck and you are supposed to connect to the red glad hand. That should fill the tanks quick but also will remove the parking brake. I could be wrong but I feel like your tanks filling up off the blue side would indicate failing check valves. My understanding is those are commonly corroded.

Hooking LMTV to shop air for CTIS troubleshooting

Hey all. Has anyone had experience hooking their LMTV to shop air so that they can troubleshoot air issues without the engine running? I tried hooking up to the front service gladhand, but the system didn’t take much air. I looked at the pneumatic schematic in the TM and I think maybe that’s...

steelsoldiers.com

To all of you. Thanks. I had no idea about check valves. And procedure for releasing air breaks. I have the operation manual. And all the PDF files. But most of this stuff I am not finding in a book. It’s all from the people that drive them.

 

[Xengineguy]

The trucks oil line of death on my truck is called the oil line of BullSh@t.! I put a wrench to it and it was almost finger tight. My kids could have taken it off.! Also, I had to remove the harmonic balancer to change the water pump belt. It had 4 of the 6 bolts finger tight.! Not joking. Now I understand why everyone says “Blue Locktite is your best friend.” But I got everything back on, except the oil line. Doing that tomorrow.

Eco Hubs! Cut your driveline speed in half. Greatly reduce noise. Increase fuel efficiency. I know sounds like a sales pitch!
It is! Eco Hubs on special thru the month of May, you get free Delta Locks.
,

 

[Ronmar]

I have it hooked up to the blue side.

Ok, you were applying the brakes. If the tanks filled, you have a bad check somewhere backfeeding the tanks...

Air brake basics:

The front glad hands are for towing.

The red one releases the park brake AND charges the vehicle tanks When air is applied.

The blue one applies the service brakes on the vehicle when air is applied, just like stepping on the pedal does.

The rear red GH will output air if you release the park brakes(applies park air) with your dash control, and apply trailer air with the trailer control right above the park control.

The rear blue GH will output air when you step on the pedal. That is why the rear GH covers are sealed. If they are not you will loose truck air when you release the park brakes or apply the service brakes.

If you back up to another LMTV and connect red-red and blue-blue you can charge that vehicles air and have full control of its brakes for towing.

The front glad-hands MUST BE VENTED. If they are not, a leaking valve can store air in those lines and cause the park brake to fail to apply when commanded, or the service brakes to fail to release when you let off the pedal...

 

[Ronmar]

Soapy water. Freaking genius! I’m working on things I can see, fixing what looks old (everything looks old). This truck is so cool but man was it neglected. And after yesterday, hearing the air leaks, it’s shined a light onto what I can’t see, or hear.
Thank you all

I start with my ears first, so you need outside air and quiet, without the kitty purring. then I feel along every line, over every fitting with fingertips. Then I bubble the fittings/unions. Of course you need to create the specific conditions where the particular lines are actually carrying air...

Don't forget the exhaust ports on the front quick release valve and rear relay valves, and the main pedal and park exhaust port which passes thru the floor up in front of the radiator, behind the grill, and of course the front glad-hand vents when park brakes are released(park air applied) and service brakes are applied... the air pressure applied to the service brake circuits is proportional to the force applied to the pedal.

A leaking treadle valve is not an uncommon issue and it will leak its air thru the valve and out its vent port port without you realizing it easily...

 

[ckouba]

Throw an air chuck quick connect on the wet tank and make an appropriate adapter to connect to your compressor. This also allows you to run air tools when the motor is running.

Random example of internet:

Super easy mod and a very handy and practical feature! Just wrench the two male connectors together to make an adapter to allow the standard hose to attach to the tank. My adapter rides in the battery box for if it's ever needed. Otherwise, a standard air hose now connects up easily.

 

[Ronmar]

Throw an air chuck quick connect on the wet tank and make an appropriate adapter to connect to your compressor. This also allows you to run air tools when the motor is running.

Random example of internet:

Super easy mod and a very handy and practical feature! Just wrench the two male connectors together to make an adapter to allow the standard hose to attach to the tank. My adapter rides in the battery box for if it's ever needed. Otherwise, a standard air hose now connects up easily.

The only issue with putting the female end on the truck is that it fills with road grime and also pretty quickly corrodes, Mine sure has(not meant to be out in the weather).

I have come to the conclusion that it is probably better to replace the wet tank drain valve with a ball valve and a male quick connect fitting. That config will still act as a tank drain when needed, and I can connect a input hose female end right to it to charge the tanks. If I need air out, I can cobble a pair of female fittings together to make an output adapter for a standard M-F air hose, or make a special female to female hose for the truck, either of which will be stored clean and out of the weather so it works when I want it to, without getting me cussing at it...

 

[Joseph A.]

Dang, thank you all.
I will post if or when I find anything.