Help needed setting front wheel bearing preload

Discussion in '80-Series Tech' started by Kernal, Feb 21, 2010.

  1. Kernal

    Kernal

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    I've tried a couple different methods for setting my wheel bearing preload (new Koyo's)and keep coming up around 13-14 lbs. This last time I tightened the inner nut to 45 ft lbs, backed off, then tightened the inner nut to 10 ft lbs, then installed the lock washer and outer nut, and torqued that to 45 ft lbs. Spun the rotor a few times each direction and checked the turning force needed to move the rotor in each direction using a digital fish scale a few times and I've been getting 14lbs. I've read here that some people like to set new bearings a bit higher than spec; is that OK or just start over?
     
  2. Cruiserdrew

    Cruiserdrew SILVER Star

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    I think you are fine. Drive a few weeks and then go back and recheck them. I use the method you do after messing around with the factory instructions for years.

    Brand new bearings can loosen up a bit. Not sure why, but it's been a consistent finding.
     
  3. Kernal

    Kernal

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    I went back out and beat on the rotor a bit with a 2lb dead blow and turned it back and forth a lot and it feels like it loosened up a bit. Then I rechecked the turning force multiple times, but now I'm getting erratic numbers mostly 7-10 but still the occasional 13-14?? I'm wondering if maybe with the new bearings fully packed with Mobil 1 red grease makes them harder to turn? I packed these using a Lisle hand packer and it completely packed in the grease so tight I could hardly turn the bearings by hand.
     
  4. turbocruiser

    turbocruiser SILVER Star

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    From what you described you did fine. Some people torque tighter for new wheel bearings to basically allow for them loosening a little. Remember though that the torque specs switch from Ft-Lbs to Inch-Lbs throughout the FSM and you have to really read carefully. :cheers:
     
  5. Cruiserdrew

    Cruiserdrew SILVER Star

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    The friction of the seal against the hub always gives a whacky reading. Plus, the synthetic grease when cold also seems to give higher than expected readings. That's the beauty of the torque on the nut method. It does away with the grease viscosity and the drag of the seal in the preload setting. Much better in my opinion.
     
  6. Kernal

    Kernal

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    In the El Mariachi DVD they retightened the inner nut to ? 48inlbs (guessing hand tight), then the outer nut to ?47 ft lbs and were getting 7-9 IIRC, but they were using Valvoline Palladium and old bearings IIRC. I tried that method and still got 13-14. My main concern was getting them too tight and damaging them but it looks like as everyone has said I'm OK for now, drive it and recheck.
     
    Last edited: Feb 21, 2010
  7. turbocruiser

    turbocruiser SILVER Star

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    I think it is actually 43 inlbs and 45 ftlbs but that's from this really rusty memory of mine. I really think that you are alright; like you already mentioned they were using old bearings and you were using new bearings. I'm sure that they have revised it by now but there were several slight mistakes made in "v 1.0" of that video. :cheers:
     
  8. lacruiser

    lacruiser

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    i tried doing 10 lbs on the inner, 45 on the outer and also ended up too tight.

    finally, I tried around 4 ft/lb inner and 45 outer, that seemed to do it.

    Basically, just about hand-tight on the inner, plus a tad more.

    BTW, a gallon of water in a milk jug, hung off one of the lugs at 3:00 will get the same reading as a fish scale at about 9 lbs or so. Hook it around the lug (coathanger wire), then very gently release the weight. If it just starts to move, you've got about 9 lbs. starting torque.
     
  9. Tools R Us

    Tools R Us

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    X2, if both seals are new, the drag number will be higher, if thicker grease is used they will be higher than thinner grease, etc. Fish scales aren't the most accurate things, depending on the pull angle, amount of force applied, etc, the number will very. IMHO too many variables for consistency.

    The bearings need preload for long life, loose bearings have short life and cause wear to the spindle, washer, etc. The higher the load on the bearing, the higher the preload needs to be for long life.

    I have seen a couple that have misread the FSM and just torqued them to 43ft/lb, ran that way long term and the bearings looked great. The early mini (same type setup) FSM calls for 18ft/lb. For stock street driven 80's, I torque them to 15ft/lb. Mine is at 20ft/lb, is a DD, but has 37's and gets wheeled as often as possible. Had it apart recently due to a leaking axle seal and the bearing parts looked perfect.
     
  10. lacruiser

    lacruiser

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    Kevin, you're saying you torque the inner lock nut to 18 or 15 ft/lb, then the outer to 43 ft/lb and call it a day?
     
  11. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    IMOP it's almost a matter of feeling .. :flipoff2: yes .. ! feeling ..

    I usually tight inner between 15 -20 and outher to 50 more less .. in my books wheel berings ( much more if you are installing everithing new ) are prone to loose with use not more tight ..

    So I preefer let 'em more tight than loose ..
     

  12. Kernal

    Kernal

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    Tool R Us: Is the 15 or 20 ft lbs the torque setting of the inner or outer nut or the amount of force needed to turn the hub/rotor with the fish scale?
     
  13. Tools R Us

    Tools R Us

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    My procedure is: Assemble everything including the inner nut. Temporally install the wheel with a couple of nuts to use as a flywheel, make spinning the hub easier and improve "feel".

    Tighten the inner nut to hand tight, spin the wheel, loosen, snug the nut tight while spinning the wheel, loosen to hand tight, this settles the tapered bearings in place. Torque the inner nut to the torque decided on, install the star lock washer and outer nut, torque the outer nut to 43ft/lb and bend the tabs.
     
  14. Kernal

    Kernal

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    I'm confused. I'm getting wide variations on the measurements from the fish scale ranging from 7 to 19, sometimes lower than than 7 with maybe an average of 12. The wide variation bothers me, at times it feels tighter than it was 10 seconds earlier?? Only thing I can feel is that one side feels tighter than the other using just the rotor (wheel not attached), but as I have no experience I have no idea how it's supposed to feel. As discussed above it seems that some of this might be due to the completely packed bearings and the new hub and bearing seals?? Maybe just call it good and recheck later. Problem is this weekend I'm leaving on a straight 1200 mile trip and may not have the time to recheck the preload.

    Edit: started over and followed the FSM exactly, getting 9-12 with the occasional 14-16 I think may be due to increased stiction from the new seals and fresh Mobil 1 grease.
     
    Last edited: Feb 22, 2010
  15. lacruiser

    lacruiser

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    I'll mention this because I've seen it done:

    don't forget when you're bending the tabs on the lock washer, they bend in BOTH directions. One tab is bent over the inner nut, and another one is bent over the outer nut. this way, the two nuts and the lock washer become one locked unit.

    I've seen more than one where the tab was only bent over one of the two. Things get a bit loose if you only do one.

    :grinpimp:
     
  16. Kernal

    Kernal

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    lacruiser; I made that mistake on the first star I did, but I bent two tabs onto the inner nut figuring I'd be doubly safe, then looked at it a second and said, oh krap, realized the mistake and fixed it by bending one tab out. I also redid the bearing preload from the start one more time, the critical factor seems to be the "hand tight" part which can induce a large viable into the equation. This last time I did it again by the FSM and used princess hands tight instead of my usual man hands tight. Now I'm getting an average of about 12 on one side and 11.5 on the other, but still with the occasional high reading. I'm now thinking this procedure boils down to experience from coming back and rechecking the bearings later, seeing if they are loose, remembering what you did and what you got before, etc, and adjusting your technique accordingly. Sound about right? I'm also wondering if there is a better scale to use instead of a digital fish scale??

    Anyone know if it is mandatory to recheck the preload on new bearings after so many miles; I probably won't have time to do it again myself for at least 5000 miles.
     
  17. lacruiser

    lacruiser

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    Well, after reading Andy and Kevin's approach, I'm inclined to just ditch the FSM procedure and tighten things up a bit.

    I drove myself crazy the first time I tried to do this according to the FSM. Every time I'd get the setting perfect by just tightening the inner nut and check with the fish scale, it would all go to hell once I torqued the outer nut. Drove me nuts!

    I finally (through much trial and error) came to the solution I posted earlier. inner set at around 4-5 ft lbs and then torque the outer to around 45 ft lbs. that seemed to end up with the FSM spec with the fish scale.

    However, as mentioned before, I noticed the bearings tended to loosen up after awhile. I actually had one come so loose that it started to spin on the spindle. Good thing I pulled everything apart for new rotors otherwise I wouldn't have noticed this. And good thing it had just started, apparently, because there was no spindle damage.

    so I'm inclined now to do what was posted above, tighten by hand, rock it back and forth, loosen, snug it up, rinse and repeat, then tighten inner to 18 ft/lbs, install washer, tighten the outer to 45 ft/lbs, lock everything down, and drive it.
     
  18. Cruiserdrew

    Cruiserdrew SILVER Star

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    Just for the record Dana, I stay with the 10 foot/pounds on the inner nut. 43 on the outer nut and bend the tabs. I really had not considered going higher, but it sounds like that's OK too. I have had no appreciable problem with this approach.

    I did have a wheelbearing failure long ago with the FSM approach. Don't know if related or not.

    [​IMG]



    Here's the thread: http://forum.ih8mud.com/80-series-tech/38087-unexpected-wheelbearing-failure-2.html
     
  19. Kernal

    Kernal

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    Cruiserdrew: I tried that method and kept getting mostly high readings, when I went back and did it the FSM method (the last time got the inner nut hand tight not gorilla tight) I got many readings in the 11-12 range with an occasional high reading up to 14-16 but also some as low as 7. Seems like as long as the end result is within the ballpark it should be OK?? I'll do the 6-12 o'clock check after about 100 miles to see if they have loosened up.
     
  20. lacruiser

    lacruiser

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    Kernal, I'd follow the advice given about making the inner nut a bit tighter, and don't worry too much about what the fish scale says. Believe me, they will loosen up. You don't want them to get too loose and start turning on you.

    I had, years ago, the bearings on my fronts so loose they rotated and scored the spindles, so I had to put on new spindles. I had checked them using the 12-6 shake method, they didn't show bad at all by that method. I think, after that experience, they'd damn near have to be falling out for them to be detected that way.

    I'm going to be re-packing and re-adjusting everything in a couple weeks, and that's what I'm going to be doing, the "12/45 ft lb and then just drive it" method.
     

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