Parking Brake not engaging '98 M1079

[Ohiobenz]

I've done some reading in similar topics, but as a new LMTV owner I'm still not sure what my next steps are.

https://www.steelsoldiers.com/showthread.php?174500-Park-Brake-Won-t-Apply
https://www.steelsoldiers.com/showthread.php?139836-LMTV-Park-Brake-not-working

following through those posts I have established this much.

1) under normal driving the brakes work
2) when all the air is dumped by opening the tank valves the brakes work
3) there is a dummy red glad hand without a vent on the front
4) with air in the tanks replacing the dummy with the vented glad hand there is constant air coming out of the vent

I can see what may be a check valve behind the bumper after the red gladhand.

What are my next steps to narrow down the problem/defective part? Can someone provide the link to the troubleshooting flowchart? I only have the Operators Manual TM here at home.

Thanks!

 

[Suprman]

You can download the tms here top section of forum. If the treadle valve/brake pedal works but the parking brake does not I would look at the front red gladhand. Take the cover off make sure its not blocked off in any way. If air is escaping there thats fine just dont block it off. Report back.

 

[Ohiobenz]

re air out of the red gladhand - see point 4 above

I removed the red gladhand check valve and and it's definitely not working - air flows both ways.
I can't get it apart so shopping for a new one atm.

hopefully that fixes it.

 

[Suprman]

Dont block off the red gladhand. Air will feed back thru the bad check valve and inadvertently release your spring brakes in park. And the truck will roll away. Which just dosnt work out well for anyone.

 

[NDT]

re air out of the red gladhand - see point 4 above

I removed the red gladhand check valve and and it's definitely not working - air flows both ways.
I can't get it apart so shopping for a new one atm
hopefully that fixes it.

I did a thread on replacing the check valve that lists a commercial part number.

 

[coachgeo]

You can download the tms here top section of forum. If the treadle valve/brake pedal works but the parking brake does not I would look at the front red gladhand. Take the cover off make sure its not blocked off in any way. If air is escaping there thats fine just dont block it off. Report back.

yep..... top forum on this bulletin board is TM's. and then the "Present conflict vehicles" forum then search that forum for "M1078" ..... which brings you too

https://www.steelsoldiers.com/showthread.php?118919-M1078-TM-s&highlight=M1078

as much as I've preach folk to search for TM's themself ..... did it myself again today and found it to be a royal PITA. very few search words that would be logical search terms worked. 1078, FMTV, LMTV etc search in that forum does not find the right thread. Have messaged Pat to see if he would be kind enough to throw those and a few others into bottom of the post as a tagline to help folk doing searches for the TM's fiind the post.

 

[Ohiobenz]

The check valve is a Haldex N-13526-BE
I removed it and using some PB Blaster and a round wire brush was able to get the crud out.
Tapping the plunger back and forth gently and blowing air through it got rid of what appears to be the rest of the crud.
Liberally soaked in Silicon lubricant the plunger slid back and forth with minimal leakage on "lung pressure" and no leakage on shop air.

Reinstalled just the check valve and now I have parking brakes!

The valves are on fleabay so I'm ordering one and then will reassemble the rest...

On to the next issue - door handles....

 

[Ohiobenz]

yep..... top forum on this bulletin board is TM's. and then the "Present conflict vehicles" forum then search that forum for "M1078" ..... which brings you too

https://www.steelsoldiers.com/showthread.php?118919-M1078-TM-s&highlight=M1078

as much as I've preach folk to search for TM's themself ..... did it myself again today and found it to be a royal PITA. very few search words that would be logical search terms worked. 1078, FMTV, LMTV etc search in that forum does not find the right thread. Have messaged Pat to see if he would be kind enough to throw those and a few others into bottom of the post as a tagline to help folk doing searches for the TM's fiind the post.

I've downloaded and printed the operators and the repair manuals - but the repair on is at work. I just downloaded the parts manual which helps me to figure out what is what. It would be nice if instead of the links just having numbers, they would be names of what each is and then embed the link... Would make searching for the right TM much easier.

 

[coachgeo]

I've downloaded and printed the operators and the repair manuals - but the repair on is at work. I just downloaded the parts manual which helps me to figure out what is what. It would be nice if instead of the links just having numbers, they would be names of what each is and then embed the link... Would make searching for the right TM much easier.

wellllllll.. don't want to spoon feed too much lol but get your point. apparently the military guys memorize the secret code when looking at the TM's to know which is which... that has apparently stayed the same over the decades. so with that you get (saved this in a text file cause I can't remember it )

With a quick eyeballing of these as I downloaded them the numbering of the LMTV 1078 manuals from 1998 is that manuals are all go something like: TM 209-2320-272-##: at least for the LMTV it seems so

With the-##: = below
. 10......... is Operations manual
. xP........... is Parts AND Special Tools
. 34........ is Maintenance AKA.. laymen's terms- General Service and upkeep
. 20........ is Service/Technical Repair manuals / for us tractor guys..... Factory Service Manuals

A hint reported by someone else: Look at the data plate on your equipment. Write down the modal number and NSN. Look at the cover of each TM. Find the proper model number and NSN. That book is for you. Then look in the section of the Parts Manual under Usable on code. Find the usable on code for your equipment and write it down. When ever looking up parts for your equipment, make sure the Usable on code, (UOC) listed next to the part you are looking up is the same as what you wrote down."