Wrecker Hydraulic issues

[4052]

The two check valves are more likely to be restrictor valves that will limit the oil flow to keep the boom from a free fall situation in the event of a hose rupture. If they were 100% check valves, you could never let the boom down.

 

[Stretch44875]

Could be pilot operated checks, where the pressure from the top of the cylinder opens the check to allow the cylinder to lower. That way, if a hose breaks, nothing moves. Very common in manlifts.

 

[Ferroequinologist]

They should be pilot operated checks.

 

[4052]

The boom is not power down. Therefore, no pilot operated check valves. The check valve is composed of the housing (two screw together pieces), a compression spring, a piston plunger , o'ring, and flat washer. The M936 uses the same setup. Even without power, the boom lowers just the same as a fork truck lowers the forks.

 

[gimpyrobb]

Huh, that sucks for you, mine is power down!

 

[brianrbull]

Does any one have the NSN or part# for the actual Check Valve? I think I found it but I am unsure, I want to try to source them and Cylinder Packings before I go home. in 54.18 days....Thanks

 

[gimpyrobb]

Brian, my email make it through ok?

 

[4052]

Nsn 4820-00-134-1122 p/n 10900080

 

[brianrbull]

Gimpyrobb, I got your email Thank you A couple interestin Items on that PDF.... I will hit you with a PM shortly.

 

[gimpyrobb]

Yeah, thats what I thought too. No hurry.

 

[m16ty]

If you need the cyl packings there is a local hyd shop and the guy can get packings for any hyd cyl made. If you have trouble finding them you can send me the old packing and I can match them up for you.