Trunnion Lubrication

[BDA]

When I built my car, I just poured some gear oil in the trubnions and assembled letting the extra oil flow out. Now that I'm getting ready for the LOG, I want to make sure they are lubed. I thought I remembered where it was advised to screw a grease zerk into the trunnion and pump the oil in with a grease gun but I haven't found that again and I'm not sure if a grease gun would work. How do you guys lube your trunnions?

[RoddyMac]

I've always lubed them as you did when you assembled yours.  But, my former boss did find an oil gun that worked on the zerk fittings.  I cant recall where he found it, but they are available.  But, I thought all the uprights had the zerk fitting already in place just above the dust seal on the trunnion, so it would be a matter of just attached the oil gun and off you go.

[BDA]

My trunnions came with a screw plugging a hole (IIRC just above the lower mount). I found a small grease gun and I plan on scraping the grease from the tube and putting oil in it. Maybe that will work. The smallest zerks I could find were 1/4 - 28 so I hope they fit.

[EuropaTC]

For some strange reason, apparently they did have blanking plugs which you were supposed to remove, fit a nipple and lubricate, then go back to the blanking plug. Strange....   like most others, I just leave the nipples in place and just give them a wipe to clear any road grime before lubricating.  I'm not confident about the thread but they are 1/4" ones because I bought some new ones earlier this year. It sounds about the right thread size, I just can't remember off-hand.

I have a Wanner grease gun which does work with hypoid 90 oil, but having tried it once it was very messy switching between grease & oil.  So now (and for the last 30+yrs)  I've just used conventional graphite grease. I know the manual says oil and yep, technically it's the correct spec for the duty but after the first time I decided to go with grease instead. There's been lots of debate on Elan forums about the grease vs oil argument with some claiming a 50/50 mixture of both works well.  The only problem I can see with grease is drying out if you leave it too long so I tend to give them a shot roughly every month.

Brian 

[BDA]

Yeah. I know about the controversy of grease vs oil. The last thing I heard was that oil was required. I have a buddy who worked for Shell Oil for 25 years. I'll ask him what he thinks.

Mixing grease and oil sounds like more trouble and mess than it might be worth! 

[jbcollier]

Grease was originally, and still mostly is, a mix of a base carrier (usually soap) and oil.  The "carrier" prevents the oil from simply flowing away.  The oil can, and does, evaporate over time leaving the soap base which has no lubricating properties in and of itself.

The trunnion forms a "cup" to hold the oil, so there is no need for a carrier.  Oil is the best choice and a gear oil is specified as the loads are high.  The trunnion is made of bronze which means you should use a GL4 gear oil not a GL5 -- though I don't think it is that important in this particular application.

[EuropaTC]

If I'm honest I think a thick oil is the best option and way back in the 70s when I got my Elan (same components) I did fill the grease gun with oil as instructed. It was a messy process but what put me off was that I used the car daily in all weathers (which means a lot of rain here) and a couple of times I noticed water droplets coming out of the rubber dust seal at the top of the trunnion.  I'd heard tales of the uprights corroding and snapping at the top of the thread as they leave the trunnion (no doubt due to lack of maintenance) but I'm a paranoid little person and so I went over to using grease.

With a technical hat on I can't see the grease ever being at it's correct operating temperature as unlike a bearing there can't be a lot of frictional heat happening, whereas an oil will flow. Hence my "give it a squirt" on a regular basis, far more frequent than the 3,000 mile intervals. It used to be every month, now not so much.....   

[BDA]

I heard back from my friend. As an introduction to him, he is retired from Shell Oil. For many years, he worked at their grease plant new New Orleans (interestingly, at the time - and maybe still - that plant made HALF the grease in the WORLD). He worked in several areas at Shell, not all involving grease, but you can imagine that he was never far from lubrication issues. Here is what he advised me:

Use a lithium 2 hydroxystearate grease with moly in it.  Virtually all modern greases with moly are lithium 2 hydroxystearate, so if you get a good moly it will work just fine. Moly is important for your application because it is the ideal lube for sliding friction.  Grade 2 grease outperforms 90W gear oil in every respect since it has low shear, high film strength, and won't seep away over time (plus it works in grease guns).

I hope that helps. 

[EuropaTC]

Now that is interesting. I can't comment on the "grease vs 90W oil" debate but your man seems well qualified to give the modern definitive answer to me, and the point about "won't seep away" is exactly the reason I chose regular top-ups of grease myself.  It's good to know a professional view because it's very easy to slip into the "xxx was good then, so it is now" when the reality is that a more modern lubricant has advantages for us.

Thanks for posting.

Brian

[BDA]

Yeah, he's the best guy I know WRT lubes although his specialty was rotating machinery (I heard he was one of the best at Shell for that - I believe it). He and I were classmates in engineering school. I had the chance to work with him at the grease plant but took a different path. I sometimes regret that but on the other hand, I wouldn't have met Mrs. BDA if I had!

[Footer]

I was thinking about lubricating the trunnions on my 73 TCS and found this post from years ago.  The thought of putting 90 weight gear oil in a grease gun didn't appear to be neat and tidy so using grease seems to be the way to go.
However, the previous post by BDA recommends a "lithiun 2 hydroxysterate with moly" .  In searching I didn't find anything that listed all those specs.

If anyone has a product name to go by for this stuff, I would be grateful.

[BDA]

Just get a moly grease from an auto parts store. Harbor Freight usually has it for those mini grease guns.

[jbcollier]

Get a simple oil can with a pump.  Fill it with GL4 gear oil.  If it has a large tip, it will work as is.  If it has a small tip, fit a bit of rubber hose.  Clean around the trunnion lube plug and then remove it.  Pump in oil until it flows out the trunnion.  Refit plug.  That’s it, takes a minute to do.

I won’t restart the great debate but Lotus did issue a service bulletin warning that using grease can lead to premature wear/failure. YMMV

[jbcollier]

https://www.amazon.ca/GOLDENROD-625-Pistol-Oiler-Straight/dp/B000VA93MK/ref=mp_s_a_1_7?crid=Y7QYE9BZC49Q&keywords=oil+can+pump+oiler&qid=1686605249&sprefix=oul+can%2Caps%2C277&sr=8-7#immersive-view_1686605275601

[Clifton]

I'm with jbcollier. Oil, GL4. I had a link bookmarked covering Alder uprights and what was used but it is MIA.

This is from a Lotus service manual.

"At intervals of every 6,000 miles (10,000 km.), remove the plug "A" (Fig.5) [1] and fit a screwed nipple. Apply a grease gun filled with 90 EP Hypoid oil to the nipple and pump the gun until oil exudes from the swivel."