Posted by Clint Dixon on Tuesday, March 29, 2005 at 10:17PM :
In Reply to: Re: Hey Joe posted by Chris on Tuesday, March 29, 2005 at 8:48PM :
I entirely understand where you guys are coming from. It can be confusing. True, most old steering knuckles do have a mixture of lubricants in them, mostly because the outer axle seals have failed. As you mention, "Leather seals = 90 wt in the knuckles". This is pretty much assured once the axle bushings become worn far enough to allow more flailing of the axle shafts than what the outer axle seals were designed to endure. When this gear lube enters the steering knuckles, or if someone puts gear lube in there on purpose, it does not hurt the tracta joints, but actually provides very good lubrication for them. However, three things that it does that are not desirable: 1) It leaks out around the steering knuckle felt wipers because they were not designed to retain gear lube. 2) It works its way into the hub and dilutes the wheel bearing grease because there is no oil seal to separate the steering knuckle cavity from the hub cavity. 3) Once in the wheel bearings, it quickly works its way past the inner hub seals (which were not designed to retain gear lube) and saturates the brake shoe linings.
Wheel bearings need the thicker grease because they are preloaded and there are no internal parts inside of the hub to flail around and sling gear lube, like the gears and other parts you find in transmissions and transfer cases. This is the same reason the rear PTO pillow block should be lubricated with the heavier wheel bearing type grease.
"Level Plug" was probably not the best choice of terminology in hindsight. "Weep Hole Plug" would probably have been better. The term "Level" seems to imply liquid lubricant. You fill the cavity with lubricant until the quantity is great enough that it just begins to run out the "Level Hole". The transfer case, transmission, Belt Drive Pulley case, steering gear box, and mechanical governor each have a level hole sealed with the insertion of a level plug.
The "Level Hole", near the underside of the each steering knuckle, really just allows for a place for air to escape as you are filling the cavity with Semi-Fluid Chassis Lubricant from your factory supplied Alemite "Gun-Lubricating, Type C, part #144 498" (grease gun), after which, a thorough mechanic would continue onward to fill the other 34 lubricating points specifying aforementioned lubricant. It also provides a convenient spot for the lubricant to escape from once the steering knuckle is almost filled to capacity. Without it, the thinner Semi-Fluid Chassis Lubricant, and whatever foreign contaminants the fresh lubricant may be pushing along in front of it (i.e.: water, dirt, misplaced gear lube), would enter the hubs and wheel bearings before one realized the knuckles were full.
Now, if the engineers at Dodge would have had a little better foresight, they could have deleted the oil seal at the outer end of each axle tube, designed a proper seal to be placed between steering knuckles and the hub cavities, and replaced the felt steering knuckle wipers with true neoprene oil wipers. If so, we would all be running gear lube in our steering knuckles and be debating more important issues like whether or not it is incorrect to call a Pole Derrick a Gin Pole and/or an A-frame. ;^)
Just my two wheat pennies worth. And for what it is worth, even with repeated and regular seal replacement, my trucks leak enough lubricant from all points, that I am just happy to accept what ever lubricant stays in there, whether there by choice or chance. ;^)
Junior