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