Question - assistance converting air park/emergency valves to single unit

[Overdrive]

Converting Air Park/Trailer Valves to Single Haldex Unit

OK, sorry for the delay I have been working on multiple modifications at the same time so have been SWAMPED...


I am waiting for my third round of quick disconnect 90 degree fittings to arrive in the mail set for Saturday. I ordered the incorrect size TWICE!!! I decided to not let the air system intimidate me any longer so I am replacing ALL the air lines that go to and from the Park/Trailer valve with new stuff as well as adding quick disconnect fittings on both ends of those lines.

I have figured out that the supply and exhaust fittings on the truck side will be 90 degree 3/8" NPT to 3/8" OD tube quick disconnect. I have been taking LOTS of pics and will update my write-up hopefully on Sunday. I purchased 100 feet of green 3/8" DOT air line tubing type2, nylon reinforced that should work nicely. It seems a lot more pliable than the stock hose and I went with green for fun as well as being able to quickly spot what I swapped out. Now that I have been messing with the valve air lines with the heater out I see how simple the setup is and am no longer scared of the air setup!

FYI: The Exhaust port behind the heater, in front of the radiator (you can see the fitting hole up behind the center of the grill in front of the heater's fresh air flap) vents two things... The Park/Trailer valve when released and the brake pedal valve.

I am going with the theory that the issue I was having with the Park valve venting to exhaust when pulled/applied is a result of me plugging the res2 line on the valve so I have uncapped that port and added another 1/4" NPT to 3/8" OD tube fitting and will be tying in a 3/8" OD tube T fitting off the truck supply line to provide two lines of air for res1 and res2 ports then give that a try... I have another brand new valve just in case so if this doesn't work I can see if the valve is the problem... Will be posting pics of all air line connections and it will be easy to see where I ran them and how with the green hose I am swapping out.

I am using a PVC pipe cutter to cut the air lines. It cuts clean and does not deform the air line.

So far here are the fittings that I am using that work on my truck... FMTVs and variants may be different.
7 each 1/4" NPT to 3/8" OD Tube push on DOT approved fittings (5 on the Park/Trailer valve and two on the cab floor for Park & Trailer connections)
2 each 90 degree 3/8" NPT to 3/8" OD Tube push on DOT approved fittings (one for the supply fitting under the dash and one for the Exhaust fitting behind the heater) - NOTE: The stock Exhaust port fitting on my truck was just a 3/8" NPT to 1/4" compression fitting, not 90 degree but I noticed that the air line loops VERY close to the windshield wiper arm so I am switching to a 90 degree fitting there. I have seen pics of other LMTVs with a 90 on there so it must just be random or if repaired whatever was lying around.
1 each 3/8" OD Tube T fitting (to split the supply line from the truck for Res1 and Res2 ports on the new valve)
1 each 100' roll of 3/8" OD DOT nylon air line (green) (to replace all the air lines going to and from the Park/Trailer valve. this project doesn't need anywhere near 100' of hose I just bought it in bulk for future)
1 each 1/4" NPT pipe plug to cap the Aux supply port on the new valve

OD

 

[Kambaku]

Thanks for the great update and all the parts details. You are inspirational!

 

[Overdrive]

SUCCESS! New valve works like a champ. The problem I was having with the valve venting to exhaust was caused by not having an air supply to the RES2 port on the new valve. You have to have two air supply connections for the valve to work. I have updated the first post with a summary and pics.

Thank you to those that helped with figuring out the switch.

OD

 

[NDT]

SUCCESS! New valve works like a champ. The problem I was having with the valve venting to exhaust was caused by not having an air supply to the RES2 port on the new valve. You have to have two air supply connections for the valve to work. I have updated the first post with a summary and pics.

Thank you to those that helped with figuring out the switch.

OD

Do A1 trucks have a second air line coming from the second air tank? Did you simply put a Y connection right behind the valve?

 

[Overdrive]

Do A1 trucks have a second air line coming from the second air tank? Did you simply put a Y connection right behind the valve?

I don't know about A1 trucks... Other FMTV variants may have different/multiple Air source lines. I just went off of what my specific LMTV has.

I put a T fitting under the dash just off the truck supply fitting. I didn't want to get too cluttered behind the new valve since the Gen2 AC units have a lot of "stuff" packed in the area under the valve and so that if I have an issue I can get to the T-fitting easily under the dash.

 

[jtron79]

Really great thread OD. We need to roll this into a definitive LMTV air brake sticky. It sucks to page through 10 threads to find those part numbers for brake chambers or rebuild kits for one way valves.

 

[Overdrive]

I completed my conversion/setup. Everything is working great with the new valve.

 

[DiverDarrell]

Thanks for this post. Just followed your lead and completed it. Great parts list. For anyone who is also installing the gen 2 a/c heater unit, make sure you make your new lines longer than the original.

 

[SamWillis]

Converting Park/Trailer Manifold Valves to Single Haldex Unit

UPDATE: Mission Complete. Successful Park/Trailer manifold valve replacement. All the follow-on posts are mostly me and others trying to figure everything out. I have summarized the switch over in this first post so you don't have to troll the entire thread.

View attachment 617231

Swapped the stock 2 valve Parking/Emergency & Trailer Brake valves for the single combined Haldex valve.

Stock valves
View attachment 617236 View attachment 617237

I also replace all the air lines (3/8" OD DOT approved) to/from the new valve and added push on, quick disconnect fittings (DOT approved) on both the truck and valve. I used a PVC pipe cutter to cut the air lines. It cuts clean and does not deform the air line.

I had to rotate both the Park and Trailer knobs 90 degrees by knocking out the little pin with a punch. The valve comes setup for a horizontal orientation.

I found all the new fittings on Amazon but can also be found elsewhere. I purchased the new air line off of eBay.

Pics of new air lines and fittings under the instrument panel. I spent some time cleaning as much as possible and added a little sound deadener after I pulled the original lines.
View attachment 617232 View attachment 617233 View attachment 617234

Original air lines

View attachment 617235

Fittings list (I replaced the truck side fittings as well).

FMTVs and variants may be different.
7 each 1/4" NPT to 3/8" OD Tube push on DOT approved fittings (5 on the Park/Trailer valve and two on the cab floor for Park & Trailer connections)
2 each 90 degree 3/8" NPT to 3/8" OD Tube push on DOT approved fittings (one for the supply fitting under the dash and one for the Exhaust fitting behind the heater) - NOTE: The stock Exhaust port fitting on my truck was just a 3/8" NPT to 1/4" compression fitting, not 90 degree but I noticed that the air line loops VERY close to the windshield wiper arm so I am switching to a 90 degree fitting there. I have seen pics of other LMTVs with a 90 on there so it must just be random or if repaired whatever was lying around.
1 each 3/8" OD Tube T fitting (to split the supply line from the truck for Res1 and Res2 ports on the new valve)
1 each 100' roll of 3/8" OD DOT nylon air line (green) (to replace all the air lines going to and from the Park/Trailer valve. this project doesn't need anywhere near 100' of hose I just bought it in bulk for future. Actual line used was about 20')
1 each 1/4" NPT pipe plug to cap the Aux supply port on the new valve

Port Identification From Truck to New Valve

Truck
EXHAUST - Release air from either valve (park/trailer)
TRACTOR DELIVERY - supplies air to the parking brake
TRAILER DELIVERY - supplies air to the trailer brakes
SOURCE - source of air from the truck (I added a T-fitting on this line to supply the Res1 and Res2 ports on the new valve)

Valve
EXHAUST - as it implies as you release the parking brake it dumps air out the fitting just behind the grill
TRACTOR DELIVERY - This is for the parking brake air
TRAILER DELIVERY - Supplies air for trailer brakes
RESERVOIR 1 - source of air from truck
RESERVOIR 2 - source of air from truck #2 - you must use both Res1 and Res2 to supply air to the new valve (thank you jtron79)
AUX SUPPLY - Capped


FYI: The Exhaust port behind the heater, in front of the radiator (you can see the fitting hole up behind the center of the grill in front of the heater's fresh air flap) vents two things ... The Park/Trailer valve when released and the brake pedal valve. This port is simply a fitting open to the environment not a one way valve.

I purchased green colored air line for this install just for fun and to quickly identify any air lines I replaced from stock. There are LOTS of different colors you can get if desired. Side benefit is that you can use a sharpie to id the lines easily on a light colored air line.

Use DOT certified air fittings to connect truck air lines to the valve. I headed down the path of finding a 3/8" OD compression fitting to 1/4" NPT fitting from Home Depot... ***DO NOT DO THIS***

Truck air systems are designed to "fail safe" so in the event a line comes loose, I doubt it, or you loose air pressure for some reason the park/emergency brakes automatically apply. They require air to release (if not caged).

Thank you to everyone who contributed to this successful conversion.

OD

Thank you for all of this excellent information regarding the switch to the single unit haldex dash park/trailer manifold. My original manifold is leaking badly so I'm replacing it and I have been researching this extensively. Your info has been invaluable. That said, I want to ensure I'm getting it right, and have made a diagram of the airlines to the manifold along with the hardware. If it isn't correct, please let me know what needs to be adjusted. Also, if it is right, I thought this diagram might be helpful to others as well.