There's always a lot of talk about wheel bearing maintenance, but nobody ever gives much thought to inner spindle bearing maintenance. Wait a minute, you say-what are inner spindle bearings?
Well, this only applies to those of you who have locking hubs (or a provision for locking hubs) on your front drive axle.
The outer front axleshaft of a 4x4 goes through a hollow spindle. The axle's sole purpose is to provide power to the wheel. The vehicle's weight is carried on the spindle by a hub that's supported with a set of wheel bearings. The spindle is bolted to the steering knuckle. Connected to the hub are the brake assembly and the tire/wheel combination. Got that? Sometimes, it is referred to a "full-floating axle."
To keep this axleshaft running straight and true, there's a bronze bushing or a set of roller bearings pressed into the hub; on early closed-knuckle vehicles, and perhaps some heavy-duty open-knuckle axles, it's usually the bronze bushing. It works just great because it's completely surrounded in heavy lubricant. The large wiper seal on the knuckle's ball assembly keeps the contaminants away. Even if some grit or water should get in, not a lot of damage will be done. The bushing's material, being softer than the axle, will absorb the grit. As long as the knuckle is kept reasonably full of lubricant, the bearing will last almost indefinitely.
While rebuilding an early frontend recently, I decided that these bushings needed to be changed, as "indefinitely" had come to an end. Believe me, the first one was a real bear. There's no inner lip to pry or pound on. After several hours of frustration and using nearly every tool in my collection (naturally not in the way they were intended to be used), I got the bushing out.
"There has to be a better way," I said, and I found it on my local Snap-On dealer's truck. It's a holding device called a split collet. The ends of the three-fingered collet are bent outward and cut at an angle, so that when driven in from one direction, they bite into the bushing, grabbing hold of it. As the collet is driven out in the opposite direction, it brings the bushing out with it.
Installation is fairly simple-the new bushings are just pressed back into the spindle.
With the introduction of the sharper-turning open-knuckle design around 1969, a set of caged needle bearings replaced the larger bronze bushing. Undoubtedly, the new design offers better support and less friction, but it can also cause more headaches. The small seal on the end of the spindle is a lot more prone to failure, allowing all that "off-road junk" to get into the spindle bearing. Even if the seal doesn't deteriorate, no one ever seems to remember that when the wheel bearings are repacked, it's also necessary to remove the spindle and repack these inner bearings. A failure not only ruins this $10 bearing but ruins a $100 axleshaft-and sometimes, a $100 spindle as well.
It's not a really fun thing to do, but there is a much easier way. The neatest tool around to do this is probably a special device called the Spindle-Lube tool that used to be available from R & T Enterprises. To use it, you have to remove your vehicle's drive flange or locking hub assembly. The tool then screws on the threaded spindle and over the axle; a grease gun is attached to the Spindle-Lube zerk fitting, and grease is pumped in around the sides of the axleshaft and into the spindle bearings. An added benefit is that pressure from the grease pushes against the seal, keeping it well lubricated and helping keep out the crud.
Okay, I am sure you noted that I used the words "used to be available." Yep-far as I can tell, the company is long out of business and the tool is no longer made. So now what? Well, you make your own tool. It will take a bit of welding, a piece of flat plate, a short length of tubing and a spindle nut. First, locate a short piece of tubing that's large enough to fit over the spindle, maybe an inch to two inches long. Weld the spindle nut to the end of the tubing, either on the inside or outside depending on your tubing size, and the style of nut you're working with. Close up the other end with a welded-on flat plate. On the one I built, I just happened to have a round piece of plate from the plug out of a hole that I had drilled with a holesaw. Drill and tap a hole on the plate for a zerk fitting. Now just screw your new tool onto the spindle and put a grease gun to the zerk. The grease will squeeze past the axleshaft and into bearing or bushing, and you will know it's full when it starts oozing out the rear seal.
This tool is not a complete cure-all, but something I consider almost a necessity. However, it still doesn't eliminate the need for periodical removal of the spindle for cleaning and inspection. However, I can't say that I remember pulling a spindle off and replacing a bearing since using the lube tool.