Front axle teardown q's
Post by brute4c on Sept 6, 2006, 11:16am
OK....after the fire, I found my diff lube to be very dark bluish in color...smoky blue I have been calling it...recall that I had a brake fire and lockout hubs were on the truck...the grease I had in the knuckles was black....my thought was that the grease had at least liquefied if not vaporized, toasted the seal inboard of the knuckle and made its way to the diff thus contaminating the fluid. Since the diff wasnt turning and the heat source was so far away and the lube is synthetic, I very seriously doubt that it could have gotten enough heat to the center section to boil the 3 plus quarts of lube for a long enough time to cause such a dramatic color change....we arent talking a little difference...but major!
In ordering parts, I wanted to get the seals that go between the knuckle and the axle tube....I thought they were just inboard of the knuckle to keep the grease in there...well no....there is a bushing just inboard of the knuckle that the axle shaft passes through and the seal is actually far inboard almost at the differential...just a bit outboard of the bearing caps.
In this view, #9 is the seal in question and #11 is the bushing.
Not having torn into one of these before...I am wondering how much clearance is there between the bushing, #11 above, and the axle shaft? I am guessing not much...enough for a bunch of grease to migrate past on its own or not? Thinking back to Brians axles, he had a ton of grease down in there but that was done under pressure....seems that bushing should make a pretty fair restrictor or what good would it be....something like .1 inch or less maybe?
Also, with the seal being at the inside edge, the only way to change them is to take out the differential right?
I have to wonder if that was the source of my discoloration or not...so far away from the heat source, I doubt the seals got that hot...maybe the passenger side due to the offset of the housing but not sure that would happen....
I would like to have all the parts on hand and do the job once....but dont want to spend more than I need to or make more work than necessary....though it would really suck to get it together and find those seals leaking...
I take it those seals are there more to keep the lube in the center section than to keep the grease from the knuckles out?
THANKS!!