Servicing hydraulic fluid

[ordaa777]

As the title says, right now the only hydraulic system related component we service is the engine driven pump, if we could keep an eye on the fluid that would be a nice touch as well.

[Metallos]

Hydraulic fluids are in closed circuits, the others not (if the engine temperature gets too high then the cooling water pressure rises and if it gets too high a vent blows off until the pressure gets lower).
I work on machines and filling up the hydraulics is the thing what I at least have to do.

[ordaa777]

Yes, what I was thinking either through leaks or through battle damage the fluid would get low, I work around around airliners and I remember a 767 that was taxiing in with quite a leak running down the right gear. It must have sprung that leak during touchdown or taxi in.

[Murder Inc.­­™]

Our SNJ-5 had quite a hydraulic leak at the 2012 MCAS Miramar airshow, we discovered it after the flight, the left strut was nearly collapsed and fluid was leaking all over the hydraulic pump on the inside port side fuselage, we had to inspect every line and hose from the pump to the gear assembelly, finally we found the pump itself was failing and had to replace it once we got back home and managed to locate one (massive price tag as always)

[Metallos]

But you don't have to service the hydraulic oil much except theres someting defective.
In normal operation you don't need to refill the oil because it runs in a closed circuit.
Changing hydraulic oil? Mostly the plane got shot down before the oil needed to be changed (maybe less on allied planes to the end of war).

On our CNC machines (are making much more operating hours than war planes) I didn't need to refill the hydraullics, only the automatic bandsaw needed to be refilled sometimes (it was around 45 years old before scrapping) due to small leakings.

[Schnellbomber]

Originally posted by Metallos:

On our CNC machines (are making much more operating hours than war planes) I didn't need to refill the hydraullics, only the automatic bandsaw needed to be refilled sometimes (it was around 45 years old before scrapping) due to small leakings.

Metallos, this is about almost 80 year old aircraft using then state-of-the-art hydraulic technology! If there was not spots of 5606 (or what ever RAF used) then the hydraulic system was DRY!! It is quite common to use pneumatics on aircraft, Spitfire used that on flaps and most Soviet aircraft used with brakes. So, yes, hydraulics do need frequent checks.

[ordaa777]

Commercial airliners also need periodic top off, leaks occur and when you do take apart lines to service the system some fluid will be lost as well. That and battle damage does sever lines.

[ordaa777]

Not sure what pressure the Spitfire system was kept at but when you have airliner hydraulic systems operating at 3,000 psi problem can pop up if there is a bad seal and whatnot.