Lubrication

[mooney2201]

Wondering if anyone is using Teflon spray on heim bearings on the landing gear...oil seem to attract dirt

[KSMooniac]

Tri Flow is what you're supposed to be using. You're right about oil... Don't use it there.

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[DCarlton]

32 minutes ago, mooney2201 said:

Wondering if anyone is using Teflon spray on heim bearings on the landing gear...oil seem to attract dirt

I think I used WD-40 to clean them and then LPS-2 to lubricate them during my last annual.  There are recommended lubricant lists for Mooney's if you search for it.  I've started using Tri-Flow in some locations particularly in the cabin where other lubricants smell.  I think it has Teflon.  

[PT20J]

Fascinating question. Heim bearings (a.k.a. rod ends), like any bearing, require lubrication or they will wear. However, when exposed to a dusty environment, oils and greases attract dirt which is abrasive and will also cause wear.

Mooney used to recommend silicone spray. In fact it is specifically called out in AD 73-21-01. Silicone spray is not a very good lubricant for a bearing, however.

The M20J Service and Maintenance Manual lubrication chart calls out " Teflon Spray (Tri-flow) or equivalent."

Tri-flow in the spray cans is a mixture of solvent, light oil and Teflon. The solvent is supposed to allow the oil to penetrate. After the solvent evaporates, the oil remains and can still attract dirt. Tri-Flow does make a dry lubricant containing Teflon which has a wax rather than an oil base. Maybe this is a better choice. But, it's not available in a spray can, so it would be difficult to apply in some areas. https://www.triflowlubricants.com/product/tri-flow-superior-dry-lubricant/

I called RBC Bearings that manufactures the Heim product line and asked what lubricant they recommended. After checking with engineering, they called back and said MIL-PRF- 81322 grease (e.g., Aeroshell Grease 22). That would be really difficult to apply to Heims that do not have zerk fittings and it would also attract dirt.

What I do is just use the Tri-Flow aerosol at annual. If the airplane were kept in dusty conditions, I'd just spray all the exposed rod ends more frequently.

Skip

[larrynimmo]

I am in annual now….this is my main lubricant for bearings and bungees specified…

with a red straw…it goes where you need it…available on Amazon…

[Guest]

LPS#2, rotate the rods to work the lubricant into the bearing, wipe up any excess with a shop towel and move on.  Tri flow is great for squeaky hinges, but doesn’t contain much lubricant.

Clarence

[DCarlton]

Dusting off this thread...  what do folks use for the yoke shaft and bushing?  Whatever lubricate was used previously is now rather gummy and sticky.  The yoke tends to chatter when you exercise it fully.  Needs to be cleaned and lubricated.  LPS2?  Thanks. 

[ArtVandelay]

Dusting off this thread...  what do folks use for the yoke shaft and bushing?  Whatever lubricate was used previously is now rather gummy and sticky.  The yoke tends to chatter when you exercise it fully.  Needs to be cleaned and lubricated.  LPS2?  Thanks. 

I use dry silicone spray.

[1980Mooney]

2 hours ago, DCarlton said:

Dusting off this thread...  what do folks use for the yoke shaft and bushing?  Whatever lubricate was used previously is now rather gummy and sticky.  The yoke tends to chatter when you exercise it fully.  Needs to be cleaned and lubricated.  LPS2?  Thanks. 

I use LPS2. 

[A64Pilot]

Heim bearings don’t really need much lubrication, more than anything your after corrosion prevention, hence the oil or grease. Typical wear occurs when there is some rust as rust is very abrasive of course.

So if I lived in a very dry / dusty climate I think I’d me more about cleaning them, I’m normally against WD-40, but for cleaning I see it’s value. I don’t normally like WD-40 as it seems to be a solvent really, that flashes off as solvents do and doesn’t leave any oil or whatever behind, but you don’t really want anything left behind here.

We learned in the Desert of South West Asia that desert dust and oil mix makes an excellent grinding compound. Take a tie wrap on a 4130 tube, a little oil and dust and the tie wrap will cut through the tube from just slight normal movement.

For the yoke if it’s getting gummy clean it off with solvent and if you need lube reapply or use a dry lube, again it doesn’t move much so lube isn’t as critical for wear

Edited May 13, 2022 by A64Pilot

[M20F]

The original links in the let’s talk lubrication thread here are all broken but Jerry Methany advises against triflow and other penetrating oils on sealed bearings.  WD-40 not going there given the drama….

[Fly Boomer]

1 hour ago, A64Pilot said:

I don’t normally like WD-40 as it seems to be a solvent really, that flashes off as solvents do and doesn’t leave any oil or whatever behind

For a lively discussion regarding what WD-40 leaves behind, just Google "WD-40 gun".  Over time, it makes an effective glue.

[A64Pilot]

Spherical rod ends, AKA Heim joints or rod end bearings are not often sealed bearings.

Are ours sealed, I’ve not really looked?

[StevenL757]

8 hours ago, DCarlton said:

Dusting off this thread...  what do folks use for the yoke shaft and bushing?  Whatever lubricate was used previously is now rather gummy and sticky.  The yoke tends to chatter when you exercise it fully.  Needs to be cleaned and lubricated.  LPS2?  Thanks. 

Silicone spray is the only thing you should be using to lubricate the control column shafts.  Clean with a towel and mineral spirits, then apply silicone spray.

No WD-40, Triflow, grease, or oils.  These will eventually gum up the guide blocks underneath the panel by collecting dust, drying, and causing things to stick.  Silicone spray leaves a nice slick finish and keeps the guide blocks clean.

[A64Pilot]

3 minutes ago, Fly Boomer said:

For a lively discussion regarding what WD-40 leaves behind, just Google "WD-40 gun".  Over time, it makes an effective glue.

Ask any painter, just about everything even acetone leaves something behind. I don’t use WD-40 myself as I believe there are better products, but surely it’s residue is minimal?

[Fly Boomer]

1 minute ago, A64Pilot said:

surely it’s residue is minimal?

Residue is apparently significant enough to completely jam a sidearm or a lock over time.  My grandfather was a locksmith.  He told me never put anything in a lock except graphite.  Once the WD-40 gets in there, the only way to get it out is disassemble the lock.

[A64Pilot]

I was going to suggest graphite, but think I remember it can cause galvanic corrosion. A lot of people seem to love carbon fiber, but it causes galvanic corrosion on many metals, aluminum for instance.

Lock wise on our sailboat I used Corrosion-X on combination locks and it worked well. I think regular application may dissolve and remove residue, but Corrosion-X doesn’t seem to contain any solvents to flash off.

Edited May 13, 2022 by A64Pilot

[Fly Boomer]

1 minute ago, A64Pilot said:

I was going to suggest graphite, but think I remember it can cause galvanic corrosion.

Yeah, I wouldn't use it on the airplane either.  I was just using the lock story as another data point for the WD-40 residue.

[PT20J]

Heim bearings: As I said above, the manufacturer recommends MIL-PRF-81322G grease. This is pretty hard to apply for bearings that don't have zerks, but since grease is a thickener + oil, just oil should be fine. The M20J Service Manual specifies Tri-Flow. Tri-Flow has teflon and solvent and leaves behind a small amount of residual oil.

Control surface hinge bearings: Some threads have suggested that these are sealed and the solvent in spray lubricants will wash out the grease. According to the manufacturer, they are NOT sealed and should be lubricated with light oil. This is what the M20J Service Manual specifies. I use LPS 2.

Control shaft: The shaft itself shouldn't need any lubricant if chrome plated. Otherwise silicone spray will make it slippery without leaving residue. Most of the problems with control friction are in the "guide" where the shaft penetrates the instrument panel structure. Mooney has used several designs over the years. The later models use a black Nylatron eyeball and socket. Mooney used to specify Tri-Flow but later said to leave it unlubricated. The problem with lubricating these is that gunk (oil/dust residue) builds up between the eyeball and socket and increases friction. You might be able to use some solvent to clean them out and then perhaps use silicone spray to free them up, but the real fix is to replace them if they are really bad.

Skip

[ArtVandelay]

I would try a liberal amount of contact cleaner to remove oil residue.

[PT20J]

2 hours ago, ArtVandelay said:

I would try a liberal amount of contact cleaner to remove oil residue.

I think that would be a great idea! Contact cleaner contains solvents to get the gunk out and is safe for plastics. A lot of aerosol lubricants contain solvents (e.g., acetone) that can damage some hard plastics, so be careful with those unless you test them first to determine compatibility.

Contact cleaner can be useful for flushing contaminants such as dirt and oil out of unsealed switches and relays. The contacts are plated with a precious metal to impede oxidation and generally depend on a wiping action to remove any slight oxidation that does form. So, switches should be exercised occasionally. It's a good idea to exercise all pull type circuit breakers once a year (during annual inspection is a good time) for this reason. Once the contact plating wears through, the base metal underneath will oxidize and contact cleaner will only be a temporary solution until the part is replaced. 

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[DCarlton]

6 hours ago, ArtVandelay said:

I would try a liberal amount of contact cleaner to remove oil residue.

And that's something I just happen to have.  Thanks.