Cruisair Gear Leg Fluid is what ...?

blimpy

blimpy

New member
Wanting to top off or drain and fill the landing gear struts on my 14-13-2 I find the manual
calls out Lockheed #5 hydraulic fluid.

I think this is only available from Authorized Tucker Car Service Centers.

So is Mil 5606 Red Hydraulic Fluid the stuff ? Aka Shell 41.

Or is it time for 'something entirely different' ?

sincerely Monty Python.
 
Interesting Dan. In motorcycles, the viscosity of the stuff you put in the front forks
has quite an effect on the damping of front forks... which the bellanca gear legs resemble
a lot.

Really, just squirting oil through an orifice of a set size... no valves or other stuff.

so, it's spring rate... and damping.

I'm really happy with the way my "forks" work now.. I've abused them pretty well
with no bottoming, or other protests.

Maybe I should just ask a viking owner what the heck is called out in thier manuals.
 
The 260 owner's manual calls for 3580 hydraulic fluid for the oleos and brakes, and 5606 for the hydraulic system. Shell lists their 3580 product as discontinued with no direct replacement. A google search shows Phillips X/C hydraulic fluid meets MIL-5606 and AFF-3580, but I don't know if it's significantly different than Shell 4 or similar MIL-5606... We've been using Shell 4 in our oleos and have been happy with the results. After replacing the dried out seals and broken springs the previous owner hadn't bothered with, of course...
 
BEWARE........many automotive hydraulic fluids are excellent paint strippers. None of that stuff comes close to any of my airplanes.
Dan
 
Back to the Tucker Authorized Service Center. Lockheed #5 meet 3850.

Yup.. no automotive stuff for me either.

I read elsewhere ( cub forum about hayes brakes) that if one mixes auto brake fluid ( Dot 3 ?)
with 5606... what you get is a mess of GUM.

Think I'll not go there.

I met a crazy hippie who stripped an entire aluminum delivery van with used auto brake fluid !
( EPA super fund site anyone ? )

there should be a spec sheet with viscosities for all these fluids.. and that is what matters ( mostly)
in shocks, struts, oleos, or whatever you like to call them
 
Viscosity is not the only property to be concerned about. For example, you also have to be aware of seal compatibility with the fluid.
 
The first thing that I was warned about when I bought my first Cruisair project was that the original gear leg seals turn to concrete if you use 5606 in them. I was told that the originals were made of Elk hide and 5606 would screw them up. After all these years I would think that they had all been changed out to modern materials compatible with the new fluids, but you cant be sure. There has been a lot of discussion of this on the forum with part numbers and dealers that sell modern replacements. Many Cruisairs have had the lower bushing machined to add an o-ring in addition to the modern chevron seals. Since you are already going to have the brakes off, it might be a good idea to pull the lower gear legs and change out the seals for modern ones.____Just my 2 cents worth.____Grant.
 
A friend (and former owner) of Bellanca told me that the early planes gear leg seals were actually made from reindeer. My wife made me promise to leave a small piece of the reindeer seal somewhere in the plane when I am done so that it will still fly. :D I am making great progress on it!!
 
Ok, well there is no evidence that the gear legs have had anything done to them.

I'm tying up the A&I's hanger pretty good already... so I'm not inclinded to take my gear legs
apart untill I have all the new parts in hand.

I am getting a little blob of fluid on the floor on the left side every time I fly.. so no doubt it is time
to renew the seals, flush the gear legs, install new springs, and put in new fluid.

My plan had been to drain, flush, and refill per the manual.

But not gonna just pull it apart and then start hunting up and ordering stuff.

And I now have 3 contradictory opinions :

use 10-40
Use 5606
Dont use 5606 untill you have new seals.

Maybe the safe thing to do in the interim is to drain, flush, and use either 10-40
or some generic hydraulic oil ( like for jacks or tractors with hydraulics ) ?

What I need in a practical way, is to be able to top up the gear legs while it is up on
jacks during the annual, just to keep it working... untill I have the parts to do the
whole magilla.
Not sure whats in there now but it looks like 90 wt on the floor.. same color same consistancy,
but haven't given it the sniff test.

---

See new post about the brakes.
 
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