Grease nipples

PostPost by: rgh0 » Fri Mar 27, 2009 11:11 am

Semi fluid grease may flow better and provide superior pubrication in some applications such as the chain drive transmission in a frazer nash but why do I need the grease (or oil if i am from the dark side and use oil) to flow in this application ?
The trunnion is 100% full of grease and all the bearing surfaces have a ready grease supply -
In fact I think I want the grease to adhere as much as possible to the bearing surfaces so maybe a higher viscosity is better.

The grease never goes hard in the can why does it "go hard" in the trunnion.

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Rohan
(another few posts on trunnions and i will catch Steve WW :D )
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PostPost by: saildrive2001 » Fri Mar 27, 2009 3:24 pm

I have 75K miles on my car when I started my rebuild. Used grease in the trunions, one side was pristine the other side the steel had corroded but the brass was perfect, go figure.
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PostPost by: mikealdren » Fri Mar 27, 2009 6:05 pm

Rohan,
I don't know why grease goes hard but it can do. When I bought my car, although outwardly good, it was suffering from mechanical neglect. When I stripped down the trunions they contained a hard grease with a texture best described as like dry soap. The trunions were scrap and so was one of the uprights.

I used oil after that.

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PostPost by: bcmc33 » Fri Mar 27, 2009 6:10 pm

saildrive2001 wrote:I have 75K miles on my car when I started my rebuild. Used grease in the trunions, one side was pristine the other side the steel had corroded but the brass was perfect, go figure.



That's probably why we refer to our cars as "SHE".
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PostPost by: rgh0 » Fri Mar 27, 2009 11:49 pm

mikealdren wrote:Rohan,
I don't know why grease goes hard but it can do. When I bought my car, although outwardly good, it was suffering from mechanical neglect. When I stripped down the trunions they contained a hard grease with a texture best described as like dry soap. The trunions were scrap and so was one of the uprights.
I used oil after that.
Mike


AH Mike - dry soap you say - I recall grease has 2 components - one is a metallic soap such as lithium sterate and one oil. Do you suppose if you never maintained the grease for many years then the oil could all be lost due to it washing out with water and heat cycles and just leaving the soap. I wonder how good a lubricant soap is - probably a bit but not much better than no oil at all which would happen if using oil and you never reoiled your trunnions for the same time these were never regreased.

The reality is that trunnion lubrication is easily done with anything - grease, semi fluid grease , oil - the bearing loads and speeds are all low and any lubricant virtually will work as good as any other - the secret is actual relubricating it regularly to put in fresh clean lubricant and remove water contamination because the top rubber water seal is poor and water a very poor lubricant


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PostPost by: mikealdren » Sat Mar 28, 2009 9:01 am

Rohan,
I agree, the grease was certainly old and even in 1980 when I bought the car, many people had lost the habit of regular chassis greasing.

I don't know enough about the stability of grease but I think is is usually waterproof, heat could cause it to break down but I wouldn't epect the trunions to get hot except, perhaps at the boundary layer. The PO lived on a farm and a year's driving down muddy tracks may have also added contaminents the the mix, it certainly ruined the brakes and helped rot the chassis.

Incidentally, the car was like this when I bought it, I always service my cars to schedule, especially the +2.

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PostPost by: bcmc33 » Sat Mar 28, 2009 10:33 am

Rohan,

If you're concerned about heat in the trunnions then isn't oil your best bet?

The mechanics at my local Lotus specialist recommend oil and not grease.

From what I have gathered, oil is also the preferred lubricant by the Triumph fraternity. But I was advised by them, for new trunnions, to run a ring of soft solder around the blanking plate as there is a high incidence of leaks if you don?t.
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PostPost by: rgh0 » Sat Mar 28, 2009 11:10 am

Hi Brian

i know lots of people recommend oil others grease others semi fluid grease. Things were slow and this topic always good for a debate so I guess i am trying to tease out any real knowledge on the topic versus the usual - I use xxx ( substitute - grease, oil, semi fluid grease) because yyy ( substitute - lotus manual, triumph guys, local mechanic, friend of a friend who was a lube engineer etc) said to. Not to say that any of the above is wrong but it is mainly all second hand rather than based on first hand lubrication tecnology knowledge

As far as I can tell it does not matter what you use provided it does not leak out and provided you change it regularly.

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PostPost by: grahammay2 » Sat Mar 28, 2009 11:12 am

How are all your recommendations for track rod ends and other pivot points down below on suspension?
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PostPost by: rgh0 » Sat Mar 28, 2009 11:47 am

The track rod ends and upper front suspension ball joints are all grease lubricated for life and sealed with a rubber boot - I guess you just throw them away if the grease in them goes hard :D

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PostPost by: Jason1 » Sat Mar 28, 2009 12:09 pm

Hi

My experience with Mini front swivels and rear radius arms leads me to agree with Rohan, most mechanics that service a Mini will just pump in enough grease it see the grease ooze out of the seals. But this leaves the old grease inside which when you take apart the swivels for adjustment you will find is rock hard. I always pump lots of grease in so as to push out the old hard grease (for Mini's).

Good quality grease, changed regularly or oil or oil/grease will all work in my opinion. My +2 is off the road at the moment as I am still working on the rear suspension, but when I get to the front I and going to try an oil/grease mix.

I think if you want lots of posts on this forum the top topics have to be Oil vs Grease in the trunions and tyre size and type. One for the stats people on the forum? :D

Jason
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PostPost by: grahammay2 » Sat Mar 28, 2009 12:54 pm

Thanks Rohan but strange my trackrod ends have nipples!
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PostPost by: rgh0 » Sat Mar 28, 2009 1:00 pm

Yes I have seen nipples fitted to some - I have always assumed these were fitted by a DPO to lube them - never seen nipples on new spares but someone may sell them that way.

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