To lube or not to lube...

[MikeC5]

That is the question...  I'm refurbishing the leaf springs on my '25 Dodge Brothers touring car, which has no shock absorbers and I'm wondering what the big dollar restoration shops do as far as lubricating the leaves on reassembly.  I've seen arguments that they should not be lubricated since the friction between the leaves provides the damping you need without shocks.  I think without lube the paint on the leaves will act as a lubricant for a short time before it's back to metal on metal. Experience/Opinions?

[Hubert_25-25]

Mike, 

     That is an interesting question.  I never knew the reason for a lack of lubricant.  My 1925 Buick Standard Shop manual states the following:

"Note:  Do not put lubricant of any kind between the leaves.  If leaves are lubricated the riding quality of the car will be spoiled and steering will be affected."  So I figured that it made it 90 years with no lube, and no ill effects.     Hugh 

[Matt Harwood]

One of my projects that I need to do on my '29 Cadillac is to disassemble the leaf springs, clean them, and lubricate them. I think they should be lubricated and the fact that most old cars came with spring gaiters suggests that they were intended to be lubricated, even those without shocks (really? It doesn't have some kind of shock absorber?). Right now, my Cadillac rides like a brick because the springs are stuck together. In my conversations with several restorers, I've gotten a variety of recommendations. One guy uses a strip of Teflon between the leaves, another uses heavy grease, and a larger consensus suggest using motorcycle chain lube, which is slippery but sticky, so it clings to the part and doesn't run out, but since the delivery system is wax-based, it evaporates and doesn't attract dirt. That's what I have decided to use on mine and this DuPont stuff is commonly recommended:

 

 

I do think the springs need to be lubricated and when you have it apart is probably a good time to do it. Any lubricant will be better than none and I think without it your springs may seize up like mine did on my Cadillac.

[jan arnett (2)]

They used to make accessories which spread the leaves and then allowed you to lubricate.  I have tried the Teflon strips and they look weird.  Have not tried the chain lubricate but I will try it on my moon.

 

[Spinneyhill]

1 hour ago, Matt Harwood said:

most old cars came with spring gaiters

That is not my experience, but you are familiar with a better class of car than I.

 

1930 Dodge Brothers 8 did not come with spring covers. 1939 Studebaker Coupe Express had front (transverse) spring covers as an option, with a multi-piece tin-plate covering. The trouble with covers is that the springs were rarely lubricated after the first few years and the old grease dried out. If the grease had graphite in it, the springs rusted pretty fast. In addition, the old grease contained a fair bit of clay, which adsorbs moisture after the grease dries out: the springs then rusted. All the rust flakes were trapped so excessive wear followed.

 

The following paragraph is in the Dodge Brothers Eight Instruction Book, June 1930:

"The springs should not be lubricated between the leaves but the rebound clips may be lubricated if necessary. If penetrating oil is used to remove rust, it should contain no graphite."

[Hubert_25-25]

Matt, 

      Buick provided "Gabriel Snubbers" on the 128" wheelbase models.  These were the long wheelbase expensive models.  Others being 115 inch and 120".  The shorter wheelbase models did not have any shocks on them.  Interesting in that they did provide the mounting holes in the frame to be able to install snubbers on all frames.  I also read somewhere that they did not recommend shock absorbers for cars that did not come with them.  It said that they actually made the springs "lighter" for the cars equiped with snubbers.  That said, My 1925 Buick Standard was the first year for Baloon tires.  I have purchased Gabriel Snubbers that I am going to refurbish to see if it makes a difference in the ride.  The snubbers are interesting in that they only work when the spring is extending since it uses a strap of webbing in the dampening process.   

So the vast majority of early Buicks have no shocks at all.  

 Hugh

[MikeC5]

Thanks all.  Hugh, I'm leaning towards no lube as the Buick appears to be similar in size/weight to the DB.  I will be interested to hear how the Snubbers affect the handling.  Surprisingly, the DB "Mechanic's Instruction Manual" is mute on the subject of spring lube.  

Edited March 26, 2019 by MikeC5 (see edit history)

[ArticiferTom]

Found this in my 1914-1927 DB/Gb Mechanic's Instr. Manual .

[nickelroadster]

I would follow what the manual says.

[Bush Mechanic]

7 hours ago, nickelroadster said:

I would follow what the manual says.

 It would seem different makes had different requirements, to keep the ride comfortable and wear at a minimum.

 

Extract from my 1923 Metallurgique handbook:_

 

Road Springs.

To retain the proper springing and to prevent breakage of spring leaves it is advisable every 1,000 miles to separate the leaves by means of a spring opener, and paint or squirt gear oil between the leaves to prevent them becoming rusty. Also occasionally paint the springs with oil as a little of this will get between the leaves and prevent water getting through. The old oil drained from the engine is quite good for this operation.

Having read this, I cleaned the rust from each leaf, and greased them well before reassembly. Just had to be particular in the de-greasing of the outside surface prior to painting. Cannot tell you how it rides, as yet. Ask me in 2 or 3 years.

 

But if the manufacturer called for no lubricant, I would heed their advice.

Edited March 27, 2019 by Bush Mechanic
Addition of info (see edit history)

[MikeC5]

Thanks Tom.  I did miss that in the MIM.   Oil it is.

[ArticiferTom]

Your welcome . My mechanic says modern cars and truck are not lubed . Doing so may cause them to flex to much and fast and break .  

[Bloo]

Modern cars have plastic parts between the leaves and do not need or want lubrication. Unlubricated springs with no such devices between the leaves will grind thin spots where one leaf contacts another, reducing the thickness, and thus the rate of the spring over time.

 

My Pontiac has zinc spring gaiters, and I squirt old fashioned graphite-based spring grease up there just like the shop manual says to do. Will they fail quicker due to the galvanic corrosion Spinneyhill mentions than if I just let the leaves grind on each other? I don't know. I do know what happens when the leaves are left to just grind, and it isn't pretty.

 

A much better answer is to have some sort of liners of teflon or plastic in between the leaves to prevent the grinding.

[ply33]

Leaf springs are inherently self-damping as the leaves rub on one another as they flex. Lubrication, with grease or more recently with teflon/plastic/whatever, between the leaves will reduce or eliminate the self-damping. You want, some damping for a good ride. The amount depends on the weight and spring rate.

 

I suspect that the difference between the manufacturer calling for lubrication or not may be related to whether or not other dampers ("shock absorbers") were fitted. Very early cars and lower end cars into the late 1920s did not come with shock absorbers so they may have relied on friction in the leaf springs for damping the motion.

[MikeC5]

ply33, that does make sense but I am sure the pre-1926 Dodge Brothers cars were not equipped with shocks from the factory.  The springs I'm re-painting had most definitely been lacking lubrication for a good part of their existence based on the wear patterns I see.  I understand these areas, near the ends of the leaves, are somewhat thinner than they were originally.  However, being near the ends of the spring (rather than near the axle loading point), I think the bending stress is much lower near the ends.  In order to prevent spring bind in these wear pockets, I have ground down the wear ridge formed so the sliding leaf above (or below) will not 'bottom out' in the wear ridge. I have also filed a small radius on the ends of the springs to avoid this from happening.  As for lubrication, there is no doubt it will slow this wear process down but, as you say, it will change the coefficient of friction between the leaves which may or may not have a detrimental affect on damping/handling.  If I find this negatively impacts either, I always have the option of taking the springs back off and cleaning off the oil...

Edited March 29, 2019 by MikeC5 (see edit history)

[Matt Harwood]

Thanks for the education, guys. I never realized that leaf springs would have also acted as their own dampers. Something new I didn't know!

[Mark Shaw]

This is all I use on leaf springs for my cars prior to assembly.  You can then spray chassis black after assembly.

https://jdparts.deere.com/partsmkt/document/english/pmac/6454_fb_GraphiteLubricants.htm

 

[Mikefit]

I just was wondering why would you like to have your vintage car ride a a modern day car just my humble opinion.  Mike

[hidden_hunter]

My 22 tell you to lube between the springs with engine oil...

[R Walling]

 I always thought that greasing the springs was a good idea, but I was told that sand would be attracted and would cause wear to the springs.

 I guess you are in trouble if you do, or don't.

[PFitz]

I've seen many leaf spring sets that were not lubed. Every set was rusted and the ends of the leaves had worn depressions into the next longer leaf.

 

Yes, oil can attract dirt and with the slight pumping action as the leaves flex, fine dirt partials can work their way in between the leaves with the flexing. That oil and dirt paste makes a pretty good abrasive compound.

 

Grease is better because the thickeners in it tend to block dirt and not allow it to get worked in between the leaves.

 

Paul

Edited April 10, 2019 by PFitz (see edit history)

[Spinneyhill]

Oil is a wetting agent, grease is not. Dirt touching oil will wet and stick. It is much less likely to stick on grease.