MLG Oleo Strut Servicing

gusc · Post by **gusc** » Thu Oct 30, 2008 03:08

I did the Maint Manual routine of filling of the oleo today for the first time and had two surprises.

The strut was full of 5606 or at least it wouldn't take any more. This is good! I wasn't able to get the fill hole up enough to make the oil flow downhill so I detached it from the fuselage. It didn't take any more oil after doing that?? Haven't figured this one out yet, how can oil flow uphill?

The other surprise was grease in the bottom of the strut, it covered about half the opening for the hyd oil? How did grease get into the strut?

I've only done one so far, am curious to see if the other side has any grease and is still full.

Post by **joea** » Thu Oct 30, 2008 09:05

Gus,

One problem with this system and people who are not used to it is that mechanics (and owners as well) sometimes see a grease fitting and think that they can merrily pump away with the grease gun until it comes out the bottom. If they do that the strut will be rock hard and usually breaks something.

Someone else can correct me but I usually put one or two pumps of grease in the strut every annual (when I did not pull the strut off like you did) and stop there. Any more IMHO is too much.

Joe

gusc · Post by **gusc** » Thu Oct 30, 2008 22:05

Joe,

I didn't make myself clear, sorry.

The grease is INSIDE the oleo, not outside. The grease was visible when I removed the 1/8" NPT hyd oil filler plug.

I have no idea how grease got into there??

aeroncafan · Post by **aeroncafan** » Thu Oct 30, 2008 22:20

My guess would be that someone has pumped too much grease and it eventually filled the case frame as Joe indicated. Once it didn't have anywhere else to go, it started making it past the packing on the oleo piston rod and started filling the oleo where the hydraulic oil would go.

I'm not the most experienced with these things, so is that scenario even possible?

Here's an excellent web site with pictures for our oleos:

http://www.hangar9aeroworks.com/Aeronca ... strut.html

MikeB · Post by **MikeB** » Thu Oct 30, 2008 22:21

Gus,
Suppose someone could have put a grease fitting in the 1/8 inch hole and pumped grease in it for some strange reason like stiffen the suspension

. Kinda like the 'no bounce' struts on my L16. Someone put what appears to be the speedometer gear out of a Ford transmission to use as a spring spacer.

Mike Berg

aeroncafan · Post by **aeroncafan** » Thu Oct 30, 2008 22:26

Hmmm....however it got there, I would think you would want to flush it out good with some type of solvent (not sure what you use here, mineral spirits???). I'd think you'd only want good 'ole "shock absorbing" hydraulic oil inside the strut.

Grease would just be too "stiff".

Holcombe · Post by **Holcombe** » Fri Oct 31, 2008 12:12

Ya, I put too much grease in mine, but not nearly as much as someone I know.
Every time you pump till it comes out the bottom, some goes up and comes out the top into the spring and down to the oil where you found it.

gusc · Post by **gusc** » Sat Nov 01, 2008 00:51

Holcombe and Fan,

Well, I wouldn't have thought that possible but it probably explains the whole thing.

There is so little that I didn't bother to try to clean all of it out, only what I could scoop out with a screwdriver. The 5606 is obviously not dissolving the grease because it was still in a lump.

The good news is that there is none in the other one!

Even better news is that neither one took more than a couple of drops of 5606 to fill.

Thanks to all for quick responses.

Post by **joea** » Sat Nov 01, 2008 08:41

Gus,

This is not unusual. You get someone who is not real familiar with this type of strut and they see the grease zerk and the rest is history. At least you found it before it broke something in the strut as this has happened when its been packed so full that it could not move inside.

Joe A

gusc · Post by **gusc** » Sat Nov 01, 2008 23:21

OK, so I gave each zerk 4-5 squirts from a hand grease gun. Is this about right?

A bunch posted about "too much", just how much is that?

The only other zerk is the TW post, the TW bearings are permanently lubed ala the lawn mower they came from!

I love this airplane, three zerks. My Navion must have had 50!!

Captgrumps · Post by **Captgrumps** » Sun Nov 02, 2008 00:47

Usually it is two.

Doug

aeroncafan · Post by **aeroncafan** » Sun Nov 02, 2008 18:28

gusc wrote:OK, so I gave each zerk 4-5 squirts from a hand grease gun. Is this about right?

A bunch posted about "too much", just how much is that?

Should be fine...Rock the airplane a bit or take it flying. If you have a good even coat on the exposed section of the strut that is within the stroke, you're most likely okay; especially if you rubbed a light coat on either it or the inside of the bushing to begin with. If you see it oozing anywhere, that's too much.

gusc · Post by **gusc** » Sun Nov 02, 2008 21:19

On the subject of grease-today I noticed grease on the nut holding the stick tube bearing halves together? I see no way to grease these bearings except maybe when it was being assembled in '03.

Any ideas on this?

Mikek · Post by **Mikek** » Mon Nov 03, 2008 11:58

gusc wrote:On the subject of grease-today I noticed grease on the nut holding the stick tube bearing halves together? I see no way to grease these bearings except maybe when it was being assembled in '03.

Any ideas on this?

If your talking about the control stick torque tube the lubrication chart in the service manual shows to lub with SAE#40 oil mixed with graphite, this like the oleo grease, should get just alittle every annual.

Gusc, where in flat rock are you based will be in Fayetteville 10-15, looking for a few airports to visit.

Mike K

Dennis · Post by **Dennis** » Mon Nov 03, 2008 12:18

Mike,

I am due east of Fayetteville about 100 miles...7M2. Gus is north east of me about 50 miles give or take. Is that about right, Gus?

On Saturday mornings @8, we have a little pilot get together for Breakfast either at the airport or at a little resturant in town.

Dennis