Announcement

Collapse
No announcement yet.

Help me understand how rear axle seals work.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Help me understand how rear axle seals work.

    Seems easy enough, right? Let me explain my confusion. I am working on a car with a bad leak on one side. Streaked wheel, soaked brakes, a real mess. I have heard over and over again, that the seals don't do much, because a spinning axle shaft flings the lube off before it makes it to the end of the bell. It then naturally drains back down the taper to the banjo housing. The only time the seal really works is when a car is parked at an angle and the lube has a way to run to the end of the axle. This is clearly not the case with the car I am working on. So, where is the flaw with the slinging lube theory?

  • #2
    Are you sure it's gear oil, and not old wheel bearing grease?
    The original seals were leather and faced the direction to keep wheel bearing grease from entering the differential.
    Modern seals should do a good job keeping the gear oil inside the tube, and the grease outside the tube.

    Comment


    • #3
      I never heard that axle shaft slinging theory. The axle housings are designed to drain the diff oil back to the center. Depending on what you find make sure that the bearing is riding concentric on the hub/ race. The races are known to flat spot on the bottom side, which can cause the wheel bearing grease to get past the seal. A worn hub can also cause a braking issue
      3 ~ Tudor's
      Henry Ford said
      "It's all nuts and bolts"


      Mitch's Auto Service ctr

      Comment


      • #4
        The theory is that when using thecaxle housing fitting that the grease seal creates a block and resistance to force the grease through and around the axle to the hub and into the bearing. The reality is that it takes a lot of grease to do that. You are better off greasing hub bearings and inspecting them as well as the hub as a service operation .

        If you have grease in the brakes you have a bad gun seal and way too much grease for past. Clean, replace/repair as needed.
        larry

        Comment


        • #5
          It is definitely smelly gear lube, and a lot of it. The grease fittings have not been used in the ten plus years I have known of the car, and the current condition just started after thousands of touring miles. I had not thought of the flat spot on the race as contributing to beating up the seal. I'll check that tonight.

          Comment


          • #6
            There are two different seals involved, outboard one that you replace in the hub, and the inboard one can only be done with the trumpet off.

            I have never found it necessary to grease the outer bearing very often at all, there is no place for the grease to disappear to, except into the brake cavity area and gum up your brakes.

            Because of this statement
            "It is definitely smelly gear lube, and a lot of it,"
            I suspect your inboard seals are shot, they are there to contain the gear oil. The hub seal is there to contain bearing grease. Two different jobs. Look at a parts blow-up from one of the suppliers.

            As far as the axle shaft slinging theory, I would add that to the category of the "made it up as I went along" theories.

            Slinging or not, if there is a bad seal somewhere, oil or grease will most definitely find its way past it.

            I will add that the axle area where the inboard seal rides is often worn down because the original leather had a lot of friction and wore down the shaft. You might be able to get a Redi-Sleeve or similar on there if this is the case
            Last edited by tbirdtbird; 05-21-2019, 12:00 PM.

            Comment


            • #7
              Just to throw this out there
              Make sure the diif is level with the fill hole and not over. I had a rear that got water in it. This not only caused it to be milky but it also leaked out the axle end..
              3 ~ Tudor's
              Henry Ford said
              "It's all nuts and bolts"


              Mitch's Auto Service ctr

              Comment


              • #8
                Typically gear lube doesn’t get that far unless there’s a scenario like Mitch said or the car is parked in an angle to drain toward one end, etc.
                using lube that is too thin also causes it to run quicker than it should as well.

                As Mitch said I’d check the level and do what’s necessary to clean it up for service and see what happens with fresh 600w lube.
                There are drain holes inside the axle housings so the lube will return to the banjo housing should it get to the axle housing .
                hopefully the holes are clear.
                i can’t say I’ve ever seen any fully clogged .
                larry shepard
                Last edited by Larrys40; 05-21-2019, 08:59 PM.

                Comment

                Related Topics

                Collapse

                • dmdeaton
                  Rear Axle Bearings
                  by dmdeaton
                  Quick question, when doing brake or axle work, do you guys pre pack the axle bearings in grease while reassembling? Or soak them in some rear end oil of choice? they are greased from the banjo oil?
                  04-27-2018, 04:37 PM
                • Beauford
                  Rear axle seals
                  by Beauford
                  So when doing rear brakes I noticed a small amount like drip on top side of bottom brake.(didnt smell bad like 600) Could this be do to jacking up the other side when doing the brakes? I really am not that comfortable tearing down the rear end and installing new seals. I heard somewhere there is a seal that can go on hub side? I know that isn't correct but thought if this was to worry about to do...
                  12-21-2017, 04:30 PM
                • carolinamudwalker
                  Greasing rear axle
                  by carolinamudwalker
                  When I pulled my rear wheels I found a big glob of fresh grease that was about to find its way to my brake linings. Obviously I pumped in there. So my question is do you pump grease in the rear axles? This may have already been covered, I cant remember.
                  06-21-2020, 09:03 AM
                • chas1930
                  rear wheel bearing grease.
                  by chas1930
                  very new to the Model ! vehicles. Inherited from my 95 year old father. 3 yrs ago I did manage to start and drive by myself. So I am learning very slow.
                  OK, my question is... rear wheel bearing were installed 4 years ago on the restore process. Now 2,500 miles later I would like to know how to lube them. I think they are sealed but not sure. I see two fittings on the backing plate. Original...
                  03-28-2020, 03:20 PM
                • Jamey E
                  Quick question for you A experts
                  by Jamey E
                  Is there anything I need to replace with doing just a brake inspection?? I plan to grease bearings while apart, but should I order hub seals or anything else before I start? I’m thinking the brakes just need adjusted, but I won’t know till we tear into it...
                  07-09-2019, 09:45 PM
                • CountrySquire55
                  Rear Wheel Bearing Grease Color Change
                  by CountrySquire55
                  Just replaced a broken left rear axle shaft in my 31 Slant Town Sedan with a good, used original shaft. When I pulled the rear drums/bearings/hubs off the car, the rear bearing grease (I used StaLube 3131 drum brake grease, a light yellow color in the can, and hand packed the bearings myself) had turned gray after about 2,000 miles of driving, about the color of anti-seize compound. There is no noticeable...
                  09-23-2017, 07:39 AM
                • wrndln
                  Packing rear wheel bearings
                  by wrndln
                  I did a search for the preferred way to pack the rear roller bearing, but found nothing in my search. Anyway, I was thinking of installing the bearings, seals and snap rings without any grease. Once that is done, then putting grease through the hole in the middle of the bearings into the bearings. Does this sound like a good plan or should I pack the bearings first before installing them (would...
                  12-12-2019, 10:37 AM
                • Rob Patterson
                  Rear axle/diff oil recommendations please?
                  by Rob Patterson
                  I'm about to fire up my speedster project for the first time.
                  Considering that it has modern inner and outer bearings and seals, a modern adjustable pinion bearing and roller thrust bearings, I'm keen to read your recommendations on a good suitable rear axle oil.
                  Many products that are available in the USofA aren't available in Australia, so I'm more interested in the specification of...
                  03-20-2019, 06:16 PM
                • Steve Plucker
                  Grease for Torque Tube bearing...
                  by Steve Plucker
                  I put Wheel Bearing grease into the cavity at the end of the Torque Tube for the roller bearing that is assembled there.

                  Now I am wondering if I had not of put just regular grease in that area.

                  I am wondering if the Wheel Bearing grease that I put in will harden up faster than the regular grease?

                  Pluck
                  04-10-2019, 09:13 AM
                • 2manycars
                  Rear hub grease seals
                  by 2manycars
                  How far in do the rear hub grease seals go on a 1940 ford rear axel?
                  10-30-2018, 11:26 AM
                Working...
                X