LMTV Brakes Not Releasing

[Frank Calandrino]

My recently purchased LMTV is stuck in the driveway and the brakes will not release. When idling it seems totally normal, no air to be heard leaking from any valves readily detectable. Last thing that I can remember doing with the truck prior to the brakes locking up was raising & lowering the cab, is there possibly an interlock between the cab position (detecting it´s not in fully lowered position) not releasing the park brake, could have gone bad? I checked out all four and rebuilt two of the KN25060 valves with the RN11V rebuild kits but they did not seem damaged, just seemed that they did not flow all that freely (by attempting to blow through them) but would certainly flow with any air pressure applied (using my compressor). No warning light on dash, emergency brake indicator lights go out on dash when disengaged. Service brakes sound and feel normal when applied and releasing foot from pedal. Any thoughts?

 

[AZK9]

My recently purchased LMTV is stuck in the driveway ...

Those are very cool MV's. While I am not in a position to help you with the brake problem... I can at least welcome you to the hobby!

Welcome from Arizona!

 

[Frank Calandrino]

I love it and can actually put it to work hauling stuff around on the weekends, much more practical that my old Alvis Saladin!

 

[NDT]

Hello, have you tried the "parking brake won't release" troubleshooting tree in TM9-2320-365-20-2? That is where I would start. Things get mighty complicated under the cargo bed with the inversion valve and anti-compounding valve and on and on.

 

[Suprman]

Check the front gladhands for obstructions.

 

[AZK9]

...much more practical that my old Alvis Saladin!

True... BUT... they are such awesome MV's!!

 

[AZK9]

Hello, have you tried the "parking brake won't release" troubleshooting tree in TM9-2320-365-20-2? That is where I would start. ...

After, NDT posted this suggestion I gave it a quick read. I agree that it seems like a really good place
to start troubleshooting the problem you've described.


A screenshot from the TM.


There is so much great information on this forum. I've found that the best way to begin solving a
problem is by diving into the TM's. Good luck!

 

[Frank Calandrino]

I believe I blew out those lines when I worked on the valves but I will double check on the next go round. Thnaks.

 

[Frank Calandrino]

Yes on the Saladin, great design & 76mm gun, packed a punch!

 

[Frank Calandrino]

I had not been to TM9-2320-365-20-2 and looks like what I need to begin troubleshooting the system, thanks!

 

[AZK9]

Yes on the Saladin, great design & 76mm gun, packed a punch!

Do you still own it?

 

[Waltjg]

Hi Frank,

Did you ever solve this problem? I just started a thread asking for help with the EXACT same problem. Then i found your thread, and another about obstructed forward gladhands... I did complete the troubleshooting steps from TM 9-2320-365-20-2--no help; and I removed the forward gladhand covers--no dice... If you resolved the issue, I would be very interested in what fixed the problem on your truck. Thanks in advance...

 

[airport jim]

I have the same issue, on a 1089 everything is working, no air leaks, spring brakes will not release, and no they are not caged. I would like to know if you were able to find the problem thanks

 

[Third From Texas]

I have the same issue, on a 1089 everything is working, no air leaks, spring brakes will not release, and no they are not caged. I would like to know if you were able to find the problem thanks

Was the truck sitting up for an extended period? Have you hit the brakes with a hammer?

I've encountered both LMTVs and M1082 trailers that had been sitting up and developed "stuck" brake shoes. A few smacks with the old 10lb sledge did the trick. Typically from being put away wet or hot and allowed to sit for an extended time.

 

[Ronmar]

Yea the brake shoes can stick to the drums, especially if wet when last parked. They are open brakes, You should be able to see the shoes move in away from the drums when you apply park air(releases brakes), just like you can see the front shoes move outward toward the drum when you step on the pedal.

A smack with a hammer, or a little gas pedal should get them to pop…

 

[Mullaney]

I have the same issue, on a 1089 everything is working, no air leaks, spring brakes will not release, and no they are not caged. I would like to know if you were able to find the problem thanks

.
SAFETY WARNING

Stuck shoes is most often the problem. Just be sure that you have a second person if you are on a hill or something to keep yourself safe. Wheels chocked or whatever it takes to keep the truck from rolling over you. Most of the time, a good solid "love tap" with a 3# hammer will free a stuck shoe. Most of the time it is only one shoe. Release the brakes, then - keeping your body out of the path of a moving truck - hit the bottom shoe and it should release.

Don't be afraid to hit it.
First time that happened to me, I worked way too hard because I was too timid with the hammer.

 

[TomTime]

My recently purchased LMTV is stuck in the driveway and the brakes will not release. When idling it seems totally normal, no air to be heard leaking from any valves readily detectable. Last thing that I can remember doing with the truck prior to the brakes locking up was raising & lowering the cab, is there possibly an interlock between the cab position (detecting it´s not in fully lowered position) not releasing the park brake, could have gone bad? I checked out all four and rebuilt two of the KN25060 valves with the RN11V rebuild kits but they did not seem damaged, just seemed that they did not flow all that freely (by attempting to blow through them) but would certainly flow with any air pressure applied (using my compressor). No warning light on dash, emergency brake indicator lights go out on dash when disengaged. Service brakes sound and feel normal when applied and releasing foot from pedal. Any thoughts?

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