No longer Stuck in Tennessee

[Glides]

Howdy.

Have a 96 lmtv ambo box rv. Pulling in yesterday, the air purged from the brake system. It purged from a threaded hole behind the grille. When I capped that, the air will escape from behind the brake pedal.
I can push the brake pedal down halfway and the air will stop escaping and the system will pump up but you cannot release the parking brakes.

Any help would be appreciated. Have a mobile mechanic here

Thanks.

 

[Glides]

Here is the valve where air popped out initially.

 

[coachgeo]

Here is the valve where air popped out initially.

where in TN? two folk pop into my mind but matters where. @simp5782 pops into my head first. He is in Memphis area. other is @tennmogger

 

[coachgeo]

.....

Any help would be appreciated. Have a mobile mechanic here

Thanks.

if your mobil mechanic is use to big rigs he should be able to get you going...... if he is an automechanic ... not so much so.

 

[simp5782]

That is just a bulkhead fitting. Running a connection line from the opposite side input to the delivery on the inside of the frame is simple enough and common DOT or JIC parts.

 

[Ronmar]

That port behind the grill is where the treaddle valve and the park/trailer control valves vent to when they release air. It needs to remain open. If you are venting air continuously from that vent port, one of those 3 valves has failed. From your description It sounds as if you may have a failed treadle/pedal valve...

EDIT: It is the easiest valve to test for. It’s vent line comes off the REARWARD FACING(toward drivers seat) side of the valve and runs around under the center dash to that vent port. Disconnect that line at the treadle. If the air is venting from the treadle continuously, then thats your problem. It should only vent air when you release the pedal.

if the air isn’t coming from the treadle then it is one of the two hand valves in the center dash...

 

[tennmogger]

Read this thread: Air brake info and troubleshooting, post #7. I can't cut and paste at the moment. That exact failure is described.

Where are you?.

 

[coachgeo]

Read this thread: Air brake info and troubleshooting, post #7. I can't cut and paste at the moment. That exact failure is described.

Where are you?.

Air Brake Info and Troubleshooting

I wanted to share some of the information I have learned about the LMTV / FMTV air brake system. I encourage you to also share the tips/tricks/etc you have found. Please do not post troubleshooting questions in this thread, let's keep this one for sharing solutions. If you are actively...

steelsoldiers.com

 

[Glides]

Well, thanks for all the information. It seems to be the brake pedal. Replaced the service valve and the trailer valve was fine. Pulled the pedal valve apart but couldn't get parts. So, it's going on a trailer in the early am and being dropped at my brother's shop. Alex Wilson helped me out a ton by phone.

Thanks for all the replies.

 

[simp5782]

Well, thanks for all the information. It seems to be the brake pedal. Replaced the service valve and the trailer valve was fine. Pulled the pedal valve apart but couldn't get parts. So, it's going on a trailer in the early am and being dropped at my brother's shop. Alex Wilson helped me out a ton by phone.

Thanks for all the replies.

Where in TN are you?

We have several parts trucks between Knoxville and Nashville along 40. And a few in Memphis

 

[Glides]

Where in TN are you?

We have several parts trucks between Knoxville and Nashville along 40. And a few in Memphis

I'm in Alcoa. It's in the process of being loaded on a trailer right now and heading back to GA. Learned some lessons today.

 

[tennmogger]

Too bad you hesitated to let us know where you were. I am 10 miles away and have had exactly that failure. That's a roadside fix if there is simply dirt in the treadle valve. Good luck.