Tech Question - Lubricating Leaf Springs

Mike,

Several weeks ago I brought two rear leaf springs to you for service and repair.
While there, you explained that automotive leaf springs shouldn't be lubricated.
There is currently a discussion of this going on in our internet discussion board.
Our manuals (1940-50 era) tell us to grease the springs. You have said that it is bad for the springs. Could you email me the reasons that lubricating the springs is bad for them?

Thanks in advance,
Ken

Ken,

Great question.
Starting in the mid 50's the steel used to make springs began to change over to SAE 5160 which does not like petroleum based products, grease/oil/etc.
Petroleum based products deteriorate the steel causing premature failure.
A great way to demonstrate this is to look at the front springs on a heavy duty truck that is leaning in the front.
There is a 99% chance that the spring on the low side is coated in oil and or grease.
Prior to the change the type steel used was not effected by much of anything. In fact, the center section of the spring was designed so the spring could be greased through the centerbolt and the grease would be spread to each leaf.
This is one of the few times you should ignore what the manual is telling you.

Thank You,
Mike