LMTV cab latch

[Smike740]

Hello,

Does anyone have a picture of the cab latch in the latched condition? I am trying to determine how far the indicator pin retracts when the cab is latched. On my truck the pin only moves in 1/4 of an inch and alot of the red portion is visible. My is pictured below.

 

[Sapphire]

Yep, it's out too far. I had the same issue two weeks ago and found that the latch pin on the cab did not lay flat enough in the cradle to allow the locking pin to fully engage. My solution was to weld a piece of 3/16" flat bar steel to the top forwardmost surface of the latch pin where it bolts to the cab frame bracket to improve the engagement angle.

The red pin should retract at least 1/8" below the level of the bezel.

To see this in action, jack up the cab part way and undo the big bolt that holds the latch pin to the cab mounting bracket on the back of the cab. Then jack the cab down slightly to relieve the hydraulic pressure on the cab latch. Finally drop the latch pin into the cradle and observe the red pin retract.

Hope this helps. Feel free to ask for clarification.

Cheers,

Sapphire

 

[NDT]

Agreed that is not enough. Before you tear into it, make sure you keep pressing the button for a while after the cab is down. Mine retracts about 8 seconds after the cab seats.

 

[Pointman0853]

I have had issues with mine as well. Here is what I did..
With the cab raised and locked up, I activated the latch with a large drift. It has to be fully latched for the lock pin to be engaged. This is how I found out how far the indicator was to be retracted. Now I just need to adjust the cab bracket so it fully engages the latch.

Pointman

 

[mkcoen]

I'm also having problems with mine. The only way I can get it to latch completely is to use a large screwdriver to pry down on the cab portion. My guess is that's it is just out of adjustment but I haven't had a chance to work on it. Just too easy to do the screwdriver trick and move on to some other task.

 

[Sapphire]

Since I have the M1079 van body there's little room for climbing up there to do anything. That's why I resorted to the more difficult repair. Just sayin'...

Sapphire

 

[Smike740]

Thanks for all the replies, I just went out and tried the screwdriver trick similar to what mkcoen described and achieved full latch. It appears that the striker portion which is on the cab is angled relative to the latch and is preventing the latch from going fully down exactly as Sapphire described. I will try adjusting the latch if I get a chance this weekend. Thanks again.

 

[TNriverjet]

I tried putting some grease on the latch mechanism, but it did not seem to help. Has anyone had any luck lubricating the pin so it retracts better?

 

[Floridianson]

Would by keeping the air bags inflated or by leaving the pins in on the air shocks help. I leave my pins in when the truck just sits and no use. My thought was it is better for the air shocks and makes the horse shoe sit higher. No problem latching though.

 

[Pointman0853]

I had trouble with mine not fully latching. I replaced the 'O' ring on the cab latch piston to eliminate that as an issue. Then, I made sure the cab was seated fully on the saddle then adjusted the bracket on the back of the cab, making sure everything was fully seated on the latch. Works like a charm now.

Pointman

 

[f8617]

My cab latch was working fine, pin fully retracting, but I noticed 1/8" play between the latch loop bracket and cab bracket...probably due to missing rubber grommet/washer. I cut a urethane bushing down to ~1/8" thickness, put it between the brackets, and completely tightened...now pin retracts only halfway (red still visible)...suggesting that some looseness is necessary for proper latching.
Unfortunately, the parts manual doesn't show an exploded view of this latch loop bracket assembly.

 

[oregonfirefighter]

Agreed that is not enough. Before you tear into it, make sure you keep pressing the button for a while after the cab is down. Mine retracts about 8 seconds after the cab seats.

Which button? My indicator button is not recessing any on it's own. I have to hop up there and give it some love. What is the purpose of the "push and turn" button? Side note- the horseshoe end of my latch had been replaced ( prior to me taking possession) and there is a TWIN plugged line running parallel running to the bottom latch assembly. (perhaps they had an issue with the original line and just capped it and left it instead of removing? I can not easily trace out the other end of it at this time.

 

[Suprman]

Push and turn control at the bottom right of the manifold controls the cab air leveling. I usually leave it on. The indicator pin on the cab latch shows when the latch is locked or unlocked. The cab can be down but if the latch is not locked then the cab is not secure down. The hyd pump may just be a bit low on fluid. The reservoir is in the pump behind the cab. There is a small fill hole with dipstick.

 

[NDT]

Which button?

The button you push to make the hydraulic pump operate.