M936A1 air line issue

rickpolak1 · Nov 18, 2018

Good morning everyone, I'm new to collecting military vehicles and our 1st purchase was a 1987 M936A1 wrecker. Overall its in great shape and everything worked flawlessly until yesterday. We took it on a 150 mile trip to our property in Okeechobee FL and had 0 issues for the 1st 148. The last 2 miles were sugar sand roads back to the property and that's when it all went to ****. I suppose the strain on the motor pushing and pulling thru the sand elevated the engine temps. it appears that the bottom of the muffler had a weak spot from old corrosion and blew out, we could immediately hear the difference. We only had about 2 miles to camp so I proceeded on not thinking it was a big deal whatsoever. I couldn't have been more wrong! The heat from the exhaust melted all 4 air lines that connect to the discharge valves located in front of the right fuel cell. My question is this....Does anyone know of a place that sells all the hoses pre manufactured? Would be nice to find them already cut to length with both fitting on for an easy swap out. If its possible, would you be cool enough to forward the information as to who sells them? If not does anyone know where I can order the correct line and size fittings and I will fabricate them myself? Does anyone know the diameter and max pressure rating the hoses need to be and the fitting sizes? Last question, some of the lines were green and others red, what's the difference?

Thank you all in advance!
Rick

simp5782 · Nov 18, 2018

rickpolak1 said:
Good morning everyone, I'm new to collecting military vehicles and our 1st purchase was a 1987 M936A1 wrecker. Overall its in great shape and everything worked flawlessly until yesterday. We took it on a 150 mile trip to our property in Okeechobee FL and had 0 issues for the 1st 148. The last 2 miles were sugar sand roads back to the property and that's when it all went to ****. I suppose the strain on the motor pushing and pulling thru the sand elevated the engine temps. it appears that the bottom of the muffler had a weak spot from old corrosion and blew out, we could immediately hear the difference. We only had about 2 miles to camp so I proceeded on not thinking it was a big deal whatsoever. I couldn't have been more wrong! The heat from the exhaust melted all 4 air lines that connect to the discharge valves located in front of the right fuel cell. My question is this....Does anyone know of a place that sells all the hoses pre manufactured? Would be nice to find them already cut to length with both fitting on for an easy swap out. If its possible, would you be cool enough to forward the information as to who sells them? If not does anyone know where I can order the correct line and size fittings and I will fabricate them myself? Does anyone know the diameter and max pressure rating the hoses need to be and the fitting sizes? Last question, some of the lines were green and others red, what's the difference?

Thank you all in advance!
Rick

is is standard 3/8" DOT air line. Sold at napa or any truck parts place. You will need some 3/8" DOT Farrels you can reuse your old air line nuts.

Green indicates secondary air lines, red indicates primary air lines, yellow indicates pressure protection and white is a vent line. No difference in the color.

Air line is cheap at NAPA

Part number H3000206 for the air line.

rickpolak1 · Nov 18, 2018

Thank you so much

simp5782 · Nov 18, 2018

If you need to get moving again just cut the air lines and put 1/4" bolts in them and use hose clamps to keep them holding pressure

Or get some 3/8" dot union connectors and cut the air lines and hook the drain lines to each other so that they can pressurize

rickpolak1 · Nov 18, 2018

Great advice, thank you. We did get it up in running after a 2.5 hr round trip to a hardware store. A handful of screws and some hose clamps later, we got it to hold enough pressure to release the parking brake. We fabricated a sheet metal heat deflector out of some old trash left in the woods and made the long and loud ride home. Instant headache from exhaust fumes and the low air pressure alarm singing as loud as she could. Great times and a successful trip though, My 17 yr old son did get to lift the 8'x8' fire pit land load it on the trailer, so all good and some lessons learned. Time to start collecting parts and materials to carry with us in the future.

simp5782 · Nov 18, 2018

rickpolak1 said:
Great advice, thank you. We did get it up in running after a 2.5 hr round trip to a hardware store. A handful of screws and some hose clamps later, we got it to hold enough pressure to release the parking brake. We fabricated a sheet metal heat deflector out of some old trash left in the woods and made the long and loud ride home. Instant headache from exhaust fumes and the low air pressure alarm singing as loud as she could. Great times and a successful trip though, My 17 yr old son did get to lift the 8'x8' fire pit land load it on the trailer, so all good and some lessons learned. Time to start collecting parts and materials to carry with us in the future.

reach up under the drivers side kick panel above your fresh air duct there and twist the connector knob for the low air alarm connection so you can turn that alarm off till you get it repaired correctly.

You can elimate all of the air drain lines. You can install the KN24000 auto drain valves. You only need two of them One mounted on your wet tank under the truck by the frame rail and one mounted on the lower tank behind the side toolbox. They will automatically drain the tanks everytime the air dryer purges to prevent water build up and eliminates the air lines. Buy them on ebay they are cheaper. They are called a DV2 valve.

M936A1 air line issue

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