Navtec A850 boom vang help please

[steveh2112]

hi, i have a navtec A850 boom vang, its a single hose hydraulic boom vang. it's not building up any pressure, maybe the pump, maybe the hose, maybe the jack, not sure yet.

what i'm not sure about is how it works. normally with a hydraulic jack, it gets longer the more fluid you pump into it, but for the vang, it needs to contract, as you pump fluid in. is this correct?

also, how are you supposed to bleed air from the system? it has no bleed nipples that i can find.

any advice about how to fix my vang appreciated, thanks

[Barry_P]

Barry P here.You are correct about vang pressure working to contract, but you can have 3 problems. Your main pump can be fubar, which would require rebuilding-apparently complicated but possible-a seal kit would be required. Is it possible the hydraulic fluid is low or empty, or is a line from the pump to the vang disconnected and blanked off or a valve on the line shut off. The third possibility is the seals leak so badly they can not overcome the 600 psi nitrogen pressure in the vang (i.e. the pressure that holds up the boom).
If the seals are so shot, they must be replaced, but here is the issue. The boomvang cylinder is highly pressurized (approx. 600 psi), and if the end cap is removed without all the necessary precautions, the shaft shoots out with possible fatal ramifications. It MUST be done correctly, so if you can isolate it to this issue, send it to a rigging shop that has and can do this.
We have this issue on our boat in Western Canada and are looking for an experienced shop to send our vang to. I am told about $300 plus shipping. At least 2-3 rigging shops on East Coast U.S can repair these.- Thanks, Barry from C&C 37, Temptress

[SAILTEC Savitt]

Dear Steve, I am searching for a hydraulics re-builder in Phuket, have you found one? Please let me know and thank you! Kevin

Originally Posted by steveh2112

hi, i have a navtec A850 boom vang, its a single hose hydraulic boom vang. it's not building up any pressure, maybe the pump, maybe the hose, maybe the jack, not sure yet.

what i'm not sure about is how it works. normally with a hydraulic jack, it gets longer the more fluid you pump into it, but for the vang, it needs to contract, as you pump fluid in. is this correct?

also, how are you supposed to bleed air from the system? it has no bleed nipples that i can find.

any advice about how to fix my vang appreciated, thanks

[steveh2112]

Parker in boat lagoon, but beware, very expensive, better to do it yourself. P.m. me if you need help