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14 bolt gear set-up questions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tRustyK5, Mar 13, 2004.

  1. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    OK, so my buddy is swapping in a 14 bolt FF into his 89 Blazer /forums/images/graemlins/woot.gif It has 4.10's and we're not doing a ratio swap. I welded the spiders into one big-assed ball (home brew spool) and pressed on some new carrier bearings.

    We marked the adjuster collars before removing the carrier but I guess with new bearings things have changed slightly.

    The passenger side collar more or less controls the backlash side of things, and the other collar should be snug I guess. This is our question: is there a pre-load number we should be shooting for on how much force it takes for the carrier to rotate? I could probably snug the drivers side adjuster another couple of holes but the carrier gets harder and harder to turn (obviously).

    We set the backlash to .0075" which I believe is right in the ballpark.

    Rene
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    According to the Randy's ring and pinion website, although there is a spec for the preload, he claims it's very difficult to go overboard, and more is better in this instance as it helps keep the backlash from opening up under load.

    Makes perfect sense to me, especially in our abusive application.
     
  3. POWERMAD

    POWERMAD 1/2 ton status

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    I asked the gearman at work about this a while ago.
    He said when set up properly that there be 0.00" end play when measured with the dail indicator.
    And just like wheel bearings if they are to tight or are preloaded then they can burn up, too loose and they will fail.
    I seem to remember someone posting about after they set up their 14FF that it got so hot that the paint burnt off of the housing.
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Endplay?

    Rene
     
  5. POWERMAD

    POWERMAD 1/2 ton status

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    Carrier bearing endplay, not backlash.
    Just like wheel bearing endplay.
    I am using wheel bearings as an example, when you set up those bearings when it is all said and done you will have no endplay.
    Same thing with carrier bearings.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    I am using wheel bearings as an example, when you set up those bearings when it is all said and done you will have no endplay.

    [/ QUOTE ]
    Uhhh, not if you're doing them correctly. /forums/images/graemlins/eek.gif The GM endplay spec for the wheel bearings on a 14 bolt FF for example, is around .008". /forums/images/graemlins/shocked.gif
     
  7. POWERMAD

    POWERMAD 1/2 ton status

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    0.008" ? hmm I seem to remember .003" being the max for used bearings. Been awhile since I looked in a service manual for the little axles though. I know that most steer axles and the drive axles on medium and heavy duty rigs have between .001 and .005"
    .008 would seem to be kinda loose.
    But that is a wheel bearing thing. /forums/images/graemlins/laugh.gif
    Rene posted Endplay??
    I was using wheel bearings as an example of endplay.
    Doc winkle was setting up a diff and using the spin method to determine the setting. I asked how he knew when it was right and he said 40 years of setting up diffs.
    But when I asked him how to know for certain he said if using the spin method makes you twichy then use a dail indicator and set them up to 0.000" end play.
    That worked for me with the last 3 diffs.
    When I welded the spiders in mine I checked it before I popped the caps and had .003" , he said that is normal with used bearings, the backlash was .018". /forums/images/graemlins/yikes.gif
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    OK, so set up dial gauge and pry the carrier both directions to find "End play"? 0.000-0.003" endplay is OK?

    The initial backlash was 0.017", so I snugged it up a little and got it down to 0.0075". Can anyone confirm that correct backlash is between 6 and 10 thou?

    Once I get the numbers good I'll run a quick pattern anyways, I just want to make sure this thing doesn't run hot or ruin bearings or anything else.

    Rene
     
  9. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    Can anyone confirm that correct backlash is between 6 and 10 thou?

    [/ QUOTE ]

    If you are between 6 & 10 thou then you will be just fine. I don't have the book in front of me, but IIRC the spec is 0.005-.012 /forums/images/graemlins/thinking.gif. My 14BFF is set up at 0.008 backlash so you should be set. /forums/images/graemlins/waytogo.gif
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    ty Ben. /forums/images/graemlins/waytogo.gif

    Rene
     
  11. 6.2Blazer

    6.2Blazer 1/2 ton status

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    I didn't think you were supposed to have any endplay in the carrier???? If there is measurable endplay in the carrier with no load on it, just imagine what will happen to it under a heavy torque load.........
     
  12. FWP

    FWP CRS

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    Hey Rene, I have a factory manual, I can look things up when I get home tonight if you still need info. I'm stuck at work til 10:30...I also have the backlash numbers for used gearsets.
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    I didn't think you were supposed to have any endplay in the carrier???? If there is measurable endplay in the carrier with no load on it, just imagine what will happen to it under a heavy torque load.........

    [/ QUOTE ]

    That's what I thought and also why I was asking for a preload value.

    Fred, pm me if you have time. I just want to make sure this gets done right the first time. It's no panic, the truck isn't being driven anytime real soon...but it does need to get done.

    Thanks!

    rene
     
  14. Beast388

    Beast388 1/2 ton status

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    Just in case anyone searches and finds this thread, here is what my Chiltons states about the carrier set-up.

    1. Place the bearing cups over the side bearings on the differential assembly and place the unit into the carrier in the axle housing.

    2. Install the bearing caps making sure the marks are lined up and intall the bolts. Tighten the bearing reatiner bolts.

    3. Loosen the right side nut and tighten the left side nut until the ring gear comes in contact with the pinion gear. Do not force the gears together. This brings the gears to zero lash.

    4. Back off the left side adjusting nut about two slots and install the lock fingers into the nut,

    5. In this order tighten the right side adjusting nut firmly to force the case assembly into tight contact with the left side adjusting nut and then loosen the right side nut until it is free from the bearing.

    6. Again retighten the right side adjusting nut until it comes in contact with the bearing. Tighten the right adjusting nut about two slots if it is an old bearing or three slots if it is a new bearing.

    7. Install the lock retainers into the slots and torque the bearing cap bolts to 100 ft.-lbs. This procedure now insures that the bearings are preloaded properly. If more adjustments are made, make sure the preload stays the same. To do this, one adjusting must be loosened the same amount the other is tightened.

    8. Install a dial indicator on the housing and measure the amount of backlash between the ring and pinion gear. The backlash should measure between 0.003 and 0.012 of an inch with the best figure between 0.005 to 0.008 of an inch.

    9. If the backlash is more than 0.012 of an inch, loosen the right side adjusting nut one slot and tighten the left side one slot. If the backlash is less than 0.003 of an inch, loosen the left side nut one slot and tighten the right side one slot. These adjustments should bring the backlash measurements into the acceptable range.

    /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif

    So it appears that there should be zero endplay on the carrier and it should have a certain amount of preload.
    /forums/images/graemlins/waytogo.gif /forums/images/graemlins/waytogo.gif
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Is it a good idea to tighten the backlash on used gears? From what I understood, running used gears with tighter backlash wasn't exactly a good idea.
     
  16. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    Is it a good idea to tighten the backlash on used gears? From what I understood, running used gears with tighter backlash wasn't exactly a good idea.

    [/ QUOTE ]

    Well, the Chiltons doesn't mention a different backlash amount for used gears. But, it does give different preload adjustments for new and used bearings. That may tell you something. I can say that I tightened up the backlash on my used gears from 0.012 to 0.008 so that it was in the "best" range. So far, so good. /forums/images/graemlins/waytogo.gif
     
  17. afroman006

    afroman006 1/2 ton status

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    I am going to do the gears on my 14 bolt soon so I have a few questions to add. They are stupid, please forgive me. How do you check backlash? I have the magnet mounted dial indicator but what do I stick the pointy end on /forums/images/graemlins/doah.gif /forums/images/graemlins/histerical.gif. I understand how do to the carrier preload now but still dont know about the other 3 measurements, carrier backlash, pinion preload and pinion backlash. I read the randy's pamphlet but it was a little over my head. I need a total newbie's guide to setting up gears, anyone know where I can find one? Thx
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    [ QUOTE ]
    Is it a good idea to tighten the backlash on used gears? From what I understood, running used gears with tighter backlash wasn't exactly a good idea.

    [/ QUOTE ]

    Well, the Chiltons doesn't mention a different backlash amount for used gears. But, it does give different preload adjustments for new and used bearings. That may tell you something. I can say that I tightened up the backlash on my used gears from 0.012 to 0.008 so that it was in the "best" range. So far, so good. /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    That's not exactly what I meant.

    I meant that if the gears have been run for 150,000 miles at .012" and now you put the carrier back in and adjust it to .006" or so, is that ok for the gears? Don't they wear in a pattern at their setting, and won't running them at a different area of the gear cause problems on a well-used set of gears?

    Tbis is only a question as I've never re-set a ring and pinion set. They go back in only the way they came out for me. /forums/images/graemlins/eek.gif /forums/images/graemlins/thumb.gif
     
  19. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    Tbis is only a question as I've never re-set a ring and pinion set. They go back in only the way they came out for me.

    [/ QUOTE ]

    Add new carrier bearings and you'll have to reset backlash and pre-load...which is exactly what we're doing. With the new bearings pressed on I couldn't get either adjuster to line up where it was before. Leaving the right hand adjuster at the marks left us with about .018" backlash...and the left side was so far out to lunch it was stupid.

    Fred actually pm'd me that exact procedure from his factory GM manual for 1974. I've printed it out and will be following it to the letter. /forums/images/graemlins/thumb.gif

    Rene
     
  20. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    I am going to do the gears on my 14 bolt soon so I have a few questions to add. They are stupid, please forgive me. How do you check backlash? I have the magnet mounted dial indicator but what do I stick the pointy end on /forums/images/graemlins/doah.gif /forums/images/graemlins/histerical.gif. I understand how do to the carrier preload now but still dont know about the other 3 measurements, carrier backlash, pinion preload and pinion backlash. I read the randy's pamphlet but it was a little over my head. I need a total newbie's guide to setting up gears, anyone know where I can find one? Thx

    [/ QUOTE ]

    Backlash: set the dial gauge pointer so the tip lightly touches the face of one tooth out near the edge. There should be a little pressure on the dial guage needle. The carrier will turn ever so slightly back and forth without turning the pinion gear. It doesn't take much pressure to rock it back and forth...

    Rock it as far one way as it goes and set the dial guage to zero, now rock it back the other way as far as it goes (before moving the pinion) and read the guage.

    Hopefully someone that's set one up will chime in with some more details for you.

    Rene
     

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