JFS Accumulator Bottle Losing 500 PSI in less than 30 mins

Operating an F-16 on the ground or in the air - from the engine start sequence, over replacing a wing, to aerial refueling procedures
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  • Posts: 4
  • Joined: 07 Sep 2012, 14:39
  • Location: fort worth texas

Unread post14 Feb 2013, 02:11

Been having an issue for several weeks now, upon servicing the hyds to 3000psi within 30 minutes the top gauge/left accumulator bottle falls to 2500 (not precharge).

Steps taken thus far:
  • Replaced jfs manifold as well as, both solenoid valves, both relief valves, all three check valves and both dump valves
  • replaced jfs accumulator
  • replaced both schradder valves and gauges
  • replaced hyd fuse and both check valves on it (not the thermal relief valve)
  • replaced brake control valve and swapped check valves on it

The precharge is done correctly and holding steady at 2200, like i said its not bleeding past 2500 which i was thinking would be some type of relief valve or check valve. everything points to a hyd leak or bleed coming from somewhere.

When bleeding the JFS accumulators to 0psi to service precharge no hydraulic fluid comes out of schrader valves indicating accumulators are serviceable.

Any past experiences or ideas are appreciated beating my head against the fi,gs and schematics currently.




  • Posts: 2
  • Joined: 28 Feb 2013, 00:11
  • Location: Eglin

Unread post08 May 2013, 17:52

JFS door actuator. Trying to remember if it is a hydralic fluid lock that keeps the JFS door closed or if bottle pressure goes thru the valve and is applied all the time to the doors. Actuator internal leak?
These bleed down problems can be a pain. Next time you are hard broke for a while,
dump the bottles and start taking loose some hyd lines in the JFS system and cap\plug them off. Then charge the bottles back up. That is the only sure fire way of isolating it.

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