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Ford 9 inch pre load question.

Discussion in 'The Hokey Ass Message Board' started by drifters cc, Jul 15, 2012.

  1. drifters cc
    Joined: Feb 16, 2010
    Posts: 178

    drifters cc
    Member

    I just changed out a leaking pinion seal on a ford 9 inch. I center punched two reference marks before I moving anything, one on the pinion shaft and one on the nut so i could reset the pre load. So every thing went smooth untill the very end. The marks are aligned but the rear turns kinda jerky (usta turn very smooth). Am I possably one full turn away or one too far in? It's hard to tell if I'm properly preloaded.
    The impact gun did not come to a dead stop or any thing like that. The yoke looked to be in position so I stoped/looked at the marks and then brought them into alignment.
    Is there any risk at atempting another revolution?
    Any one else have this issue?

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  2. Do you have the pinion assembly out of the 3rd member? If not, pull the 5 bolts out and check the drag with the assembly in a vise.

    If it's jerky with the pinion assembly out of the housing, it sounds like you're way too tight...
     
  3. railroad
    Joined: Feb 3, 2010
    Posts: 242

    railroad
    Member

    You may need to go past your marks. Think of it like tightening your front wheel bearings. With the ring gear in the way it is hard to feel the preload. Make sure you do not have any in and out play, like pulling the yoke out and pushing in. If you can turn the assembly with the yoke it should be smooth. If you cannot sleep good, pull the pinion mount.
     
  4. fogs58
    Joined: Jan 14, 2011
    Posts: 135

    fogs58
    Member
    from ooo

    I agree with exwestracer. Once a crush sleeve has been " crushed" for pre-load it dosent always take alot to go past it with a good impact. I've done it myself before.
     

  5. Couple of points here.

    You must remember that the bearing pre-load spec is for new bearings. If i understand what you have done correctly then you have retained the old bearings and simply fitted the new seal. You don't set up old bearing in the same way as new ones. The pre-load spec is to allow the bearings to "reak-in" and they do loosen up.

    Using an impact gun is really a no-no on a job like this. Should be tightened by hand. Keep winding until the endfloat is taken up and then watch to restore the nut to the alignment mark. I would say you have overtightend the pinion nut.

    Crush sleeves . What do they do ? They provide resistance to the pinion nut. In blunt terms they stop the nut from falling off. In doing this it enable the nut to remain exactly where you want it because the position of the nut is what give rise to the pre-load on the bearings not the sleeve.

    Problem; once used the crush sleeve is used generally it is a throw away item and should be replaced. By reusing it you can fall into the trap of overtightening the pinion bearing because the sleeve is not offering the resistance it should. This is likely to lead to bearing failure.

    In your case I would back off the pinion nut and start again . Tighten to remove endfloat and see where your alignment mark is . Once you have taken the free play out of it ensure the pinion is rotated after every incremental tightening. Keep going until you find your mark. Hopefully you can get back to where you were before you replaced the seal.

    Ideally, with the 9 inch as you can set up the pinion pre-load on the bench. It is advisable to take the pinion out and get a feel for the pre-load before you dismantle it. That way in a pinch you might get away with not replacing the crush sleeve. In a pinch I have seen shims behind crush sleeves to pack them up to keep the nut tight. Good luck!
     
  6. I used to check the pinion turning torque before disassembly and then set it 10 inch pounds heavier when put back together. Use Lock-Tite on the pinion nut threads when retightening.Use a beam inch pound torque wrench not the click type.
     
  7. 57Custom300
    Joined: Aug 21, 2009
    Posts: 1,388

    57Custom300
    Member
    from Arizona

    I agree with the others that it's too tight. Kind of hard to get it right if you havent done a few. On a side note with dealership labor revenues declining, they have hired an army of kids to work in the "fast lane" to find problems. Pinion seals are one of the targets. I used to watch these kids gleefully taking the impact to them without a clue to what they were doing. Glad I'm not there anymore.
     
  8. milner3268
    Joined: Oct 1, 2010
    Posts: 283

    milner3268
    Member
    from buffalo NY

    Yep sounds like your in to far or a little to tight on the PRE crushed sleeve . Id take the nut back off put some locktight on it and reassemble it and if it goes back where it was [too tight ]slightly back it off till it spins free, should be fine
     
  9. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,306

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Both parts are important.....the crush sleeve isn't just 'to hold the nut on'.

    The crush sleeve is in fact a 'variable length spacer'. The bearing pre-load result from the spacing of the inner races of the front and rear pinion bearings. At some dimension, they are close enough together to "load" (or space) the bearing rollers the desired amount.

    That could be done with a fixed length spacer and shims. The beauty of the crush sleeve is it's compressibility to a desired length while still retaining enough 'resistance' to shortening further that bearing load, once set, doesn't change other than as a result of bearing wear.

    The nut plays a role in this by first applying pressure enough to compress the sleeve to the desired length and then maintaining it's dimension to keep all the parts in the 'sandwich' together as intended. That is as much due to the fact it is a lock nut as it is the torque against the crush sleeve.

    The most conservative procedure calls for replacement of both the sleeve and the nut when the assembly has been loosened and/or partly disassembled, as when replacing the seal.

    It is possible, obviously, to reuse the parts, but great care need be taken to regain, but not exceed, the correct preload when setting up used parts. I totally agee with your comments regarding the inadvisability of using a impact wrench for setting prelaod.

    Ray
     
    Last edited: Jul 16, 2012
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 50,927

    squirrel
    Member

    A new crush sleeve costs four bucks....

    Thanks for the explanation Ray.
     
  11. Hnstray,
    Re-read what you have written. There is nothing there that describes anything other than what I stated above. That is, the crush sleeve does nothing other than provide considerable resistance against the nut thus preventing it from coming undone and falling off.

    The fact is you can run the pinion bearings without the crush sleeve and still achieve the same preload. That is purely a function of how far you wind the nut on. Of course you need some otherway to hold the nut in place to stop it coming loose. Try it and you will see what I mean.
     
  12. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,306

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I think I'll stick with using the components installed as engineered.

    I 'edited' my post to delete your quote........hope that works better for you.


    Ray
     
    Last edited: Jul 16, 2012
  13. I see your point, but the explanation is very misleading. The crush sleeve is there to stop the bearings moving back and forth. The bearings have a certain amount of "give", and without the sleeve there is no way to keep tension on the assembly (hence the "preload"). Sure, it provides resistance against the nut (but it's a lock nut anyway), but that is not its primary purpose.
     
  14. Sorry , but this is just plainly wrong.

    The two bearings are tapered roller bearings. The inner race is a interference fit on the pinion shaft. The inner race at the front bears against the rollers which in turn bear against the outer race which is firmly pressed into the pinion retainer housing.

    The load then bears through the housing and against the other outer race. The load then bears against the rollers and then the inner race of the bearing that bears against the back of the pinion gear. The sleeve plays no roll in that at all.

    Essentially the same as a front wheel bearing . You tighten the nut to take up the play. If you keep going you will load up the bearing or "pre-load" it. This is no different.

    I recall my trade school instructors explaining what it does very clearly when I learned how to overhaul diffs. He quite emphatically stated that the sleeve basically stops the nut from coming off.

    The only other thing it will assist with is because the inner races are in tension against the nut then this will assist in preventing the inner races from rotating on the pinion shaft itself. The pinion bearing pre-load is purely a function of how far you turn the pinion nut as in the wheel bearing example above.
     
  15. drifters cc
    Joined: Feb 16, 2010
    Posts: 178

    drifters cc
    Member

    Guys, thanks for all the helpfull insight so far.
    Will not have a chance to make it out to the garage tonight or tommarow.
    Maybe I'll open up the front support Wednesday.
    Didnt really expect to have trouble just pulled the yoke and seal /replaced the seal and yoke. But when I began to draw the yoke in I could feel that drag or jerky ness as the pinion would slightly move. The more I tightened better it rotated. I just didnt want to go too far and have to pull the whole mess apart. If I go too far how will I know?
    As for "end play" there was none for the last quarter inch or so as I was drawing it in.
    The rear is on jack stands and (maybe this was a mistake ?) I let it tip forward slightly when the yoke was off to drain. Could the shim/slinger/crush sleeve/or bearings have become mis aligned and then forced back together?
     
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 50,927

    squirrel
    Member

    My guess of what happened: Before you tightened it enough to remove all the end play between the bearings, the pinion was not held in the proper position, so the ring and pinion were not meshing properly and it would not turn smoothly. But when you took up all the play, it felt "right".

    I wouldn't mess with this with the pinion in the car, I'd pull the 5 bolts and remove the pinion and retainer assembly, and work on it on the bench.
     
  17. cosears
    Joined: Apr 30, 2011
    Posts: 17

    cosears
    Member

    Really good explanations and details. What you did by marking the pieces was correct, where you made the mistake was not counting each turn of the nut when taking it off and replacing the nut with the same amount of turns. Works every time. You could then check with torque wrench but once you crush any further you are screwed.
     
  18. All I can say is try it without one... The nut coming off will be the least of your problems. Guess we'll have to agree to disagree.
     
  19. Technically, in a odd way, freduece is correct.
    Although, as exwestracer stated "try it without one". Disaster will strike you in the rear (literally) in a short amount of time.

    Soooo... You are both correct.
     
  20. NV rodr
    Joined: Jul 23, 2006
    Posts: 155

    NV rodr
    Member
    from Reno, NV

    For me a new nut and crush sleeve are so cheap that its just not worth taking a chance on a comeback that doesn't pay enough to do it twice. Just my opinion.
     
  21. 302aod
    Joined: Dec 19, 2011
    Posts: 275

    302aod
    Member
    from Pelham,Tn.

    Never checked a used one, but with new parts the preload is 15 inch pounds of drag, with a beam type torque wrench.
     
  22. KeithDyer
    Joined: Mar 26, 2007
    Posts: 193

    KeithDyer
    Member

    So am I the only one who keeps Ratech spacer and shim kits in the toolbox??

    Have torn down some drag race third members with the crush sleeve not where I left it!!!

    Take care, K
     

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