The average repair man is apt to have more call to lubricate the leaves of a spring than any other one thing in connection with springs. True, they lose their temper, sag, and show signs of losing their set; plates break in the middle, at the bolt hole, and near the ends of the top plate; and inside plates break in odd places. More frequently, springs make an annoying noise, a perceptible squeak because the plates have become dry and need lubricating. When this happens, and the up or down movement of the car rubs the plates over one another, dry metal is forcibly drawn over other dry metal with which it is held in close contact; naturally, a noise occurs.
To take care of this job, it is well to construct a spring leaf spreader. Of course, the job is best done by jacking up the frame, dismounting the spring entirely, taking it apart and greasing each side of each plate thoroughly with a good graphite grease, then reassembling, and putting back under the car. This is the best way, but it costs the most and few people will have it done. Sometimes spring inserts are used; these are thin sheets of metal of the width and length of the spring plates, having holes filled with lubricant over which is a porous membrane.
For the ordinary spreading job, the plates must be pried apart and the grease inserted with a thin blade of steel, for instance, a long-bladed knife. To spread the leaves, jack up the frame so as to take off the load, then insert a thin point and force it between a pair of leaves. In Fig. 90, two forms of tools for doing this forcible separation are shown. The first is a solid one-piece forging with the edges hardened. It is used by sliding the edges over the ends of the spring leaf, then giving it a twist to force it in between them, as shown in the figures. The second tool is intended to be forced between two plates by drawing back on the handle.
Fig. 90. Handy Tools for Spreading Spring Leaves to Insert Lubricant.
When springs lose their temper or require resetting, it is better for the average repair man to take them to a spring maker; this is a difficult job, requiring more than ordinary knowledge of springs, their manufacture, hardening, annealing, etc. When springs are in this condition, they sag down under load and have no resiliency. If a great many springs are handled, a rack like that shown in Fig. 91 is well worth making. Broken Springs. When springs break, there is but one shop remedy, a new plate or plates. But when they break on the road, it is necessary to get home. When the top plate breaks near the shackled end, repair this sufficiently to get home by using a flat wide bar with a hole in one end big enough to take the shackle bolt; bolt this to the spring in place of the end of the leaf which is broken.