Front rear input shaft bearing

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Dino soar, May 26, 2020.

  1. Dino soar

    Dino soar Road Train Member

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    95 fld120 40,000 lb Meritor rears.

    I have a little bit of up-and-down play on the Yoke on my front rear. The yoke is new.

    I had a very small amount of vibration at certain times and I went under the truck and I saw that I had play in the yoke. I pulled the drive shaft down and hammered down on the Yoke nut. It did tighten a little but I still have up and down play. It is very minimal but it is enough that I can feel it.

    I would like to fix this while it is still a minor problem. It looks as though I can remove the Yoke and the bearing cage and replace the bearing and race. Does the bearing have to be pressed on to the input shaft?

    I believe it is the shims that give the preload for the bearing. How do you establish the proper preload?

    Also should I stop at the bearing that is at the cage or do I continue to go backward and look at the fork and the spring and the bearing for the rear side gear? Is there anything else to do while I'm in there?
     
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  3. Dale thompson

    Dale thompson Road Train Member

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    I only have experience with Eaton, need a dail indicator and torque spec for the nut (holding yoke) is big like 900 plus ftlbs
     
    Dino soar Thanks this.
  4. mtntopbound

    mtntopbound Bobtail Member

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    Yes the bearings do press on the input shaft, and the shims behind the bearing plate set the pinion preload. You can pull the bolts out of the Bearing plate and the input assembly will come out of housing without removing the yoke, then you can remove a thin shim and that should take the slack out. Wear in the spider gears in the power divider are usually where the slack comes from.
     
  5. Ridgeline

    Ridgeline Road Train Member

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    Dude, i will offer you a bit of important advice



    When it comes to rear axles, unless you have experience with them, let someone else who does have experience with them fix them. Some need tools that you don't have, as mentioned the preload and torque is really high.


    What's it sounds like you have a disaster in the making, any play in the pinion can lead to a failure.
     
  6. Dino soar

    Dino soar Road Train Member

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    So you think that the play is not a problem with the bearing it's a problem with wear in the spider gears?
     
  7. Tug Toy

    Tug Toy Road Train Member

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    Look up the Eaton worksheet. To give instructions and tolerance in plain English. If you can get the yolk nut off the rest is ez. Just follow the instructions and about $30 in harbor freight tools if you don’t already have dial indicator and a caliper.took me about 3 hours but I was taking my time and had to do it about 3 times till I felt good with it. That was 300k miles ago. I’m at 1.1 now and could go at any moment but so far so good.
     
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  8. Rideandrepair

    Rideandrepair Road Train Member

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    Sure it’s not just the yoke loose? Happened to me, years after replacing the seal. Tightened it up with a big gun, been good since.
     
  9. Dino soar

    Dino soar Road Train Member

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    I see how it comes apart in the Meritor service manual. It is not a problem to get the nut off or to retorque it. I have a dial indicator and a set of calipers.

    I see in the manual now how it is that I set the bearing with the shims.

    And is it just the bearing itself that is the problem?
     
    Last edited: May 26, 2020
  10. Dino soar

    Dino soar Road Train Member

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    I hammered it down with my 3/4 inch air gun the same as I used with all the other Pinon nuts. It definitely has play inside somewhere.
     
    Rideandrepair Thanks this.
  11. mtntopbound

    mtntopbound Bobtail Member

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    A lot of times it's in the nest assembly or the brass washer behind it. It doesn't take much to create some play and get a vibration under a load.
     
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