Air Valve- front rear tire R

[saratoga]

I'm having trouble building air pressure in M1089.

After I turn off, I hear hissing from the pictured valve around the bottom gasket. muffled when i cover with hand

is it stuck or do i need to pull lines off and have rebuilt?

 

[simp5782]

Relay valve

Common commercial part. Just replace it.

 

[saratoga]

its in the middle of a field. found the relay valve in tm, thanks.
think there is anything i can do to get out before?

 

[NDT]

Cage the brakes but for heavens sake not if there are any grades or on public roads.

 

[saratoga]

caged when i towed from govplanet. level grade on property, ill tow with grader

cant figure out why it went out of no where.
local guy came over and told me i was engaging trans and releasing brake in wrong order. could i be doing something wrong?

 

[simp5782]

It's got a rubber diaphragm that went out. The rubber is probably 10yrs old if not older. It just gave out and and started venting. Better than it going out and applying air to the brakes locking them up and not venting. This happens alot on trucks primarily used offroad. Junk can get under the flap and cause issues

 

[NDT]

The order of brake release/ putting in gear has nothing to do with anything. Simp is right, these parts are old and used low quality non-milspec commercial components to begin with.

 

[simp5782]

Haldex # N50004D or E. Just google or ebay search. Really any R12 valve would work but you may have to have bushings to adapt to the port size fittings you currently have

 

[saratoga]

valve is almost same price as rebuild kit. waiting to hear about shipping. is there a trick to get those hoses off?

 

[simp5782]

They are just JIC on the big hoses they will just swivel right off. The 2 or 3 dot fittings should come right off as well.

 

[saratoga]

ended up buying wrong one. i cant figure out what the valve number is. anyone out there better than me at this? i tried N50004D

 

[simp5782]

Your old one should have a tag on it. If it does not then post a pic of the valve and how many ports say Del, serv, sup.

It is an R12 valve more than likely i doubt its an R8 . They can have a few various forms of look but serve the same purpose

 

[simp5782]

Also take a pic of a more general location on the truck. I see another relay valve in the background behind it. Relay valves are usually on each axle set

 

[saratoga]

ill start it up tomorrow and check, i think last time air was only leaking from bottom one
its m1089 wrecker

 

[saratoga]

both rear front are flat. when this started it was only driver side rear front.

 

[simp5782]

The top valve is an anti compounding type relay valve part number N50024B

Bottom one is a standard KN28080 for new or KN28080X for a reman

That valve is not listed in the TM

 

[saratoga]

thanks, its comes tomorrow. i looked forever in that TM

 

[saratoga]

its the bottom one

 

[BRob18E]

**** Wes, I must say, the more I read on this site the more I respect your knowledge. You sound like me, I'll dig into anything, but you have tons of experience with all the military vehicles and your knowledge helps many. Keep up the good work.

 

[saratoga]

just got the time to take out but i cant get the fittings off the valve? is there a trick or should i just go buy new ones?