1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Unsteady at freeway speeds after birfield rebuild

Discussion in '80-Series Tech' started by Lankan, Oct 11, 2017.

  1. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    I had my birfields rebuilt last weekend with all OEM knuckle and wheel bearings. Before the replacement the truck was very controllable at highway speeds (anything over 50mph).

    It was very apparent that afterwards (on my drive home from picking it up), that it was very "twitchy" on the highway, requiring me to correct side to side movement constantly.

    Even though I knew my alignment was good, I got it re-checked yesterday, as the mechanic that did the rebuild said that one of my knuckle bearings fell apart when he removed it (so I thought maybe my previous alignment prior to this rebuild was thrown off by the new bearings. Alignment came back perfect... I will post the results below.

    Any idea what could be causing this? I have been on a 3.5" Slinky lift with Slee castor plates for almost a year without a problem. Only work done over the weekend was the knuckle rebuild. Would anyone know what the culprit could be?
     
  2. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    The alignment print-out...

    20171010_225457.jpg
     
  3. Rifleman

    Rifleman

    Messages:
    1,002
    Likes Received:
    527
    Joined:
    Feb 4, 2015
    Have them go back and check that the steering arms are seated all the way flush on the knuckle housing. Along with that, recheck the torque on the nuts (71 Foot Pounds) that hold the steering arms to the knuckles. Next check the per load on the wheel bearings "Tools are us" says to use 30 foot pounds of preload torque on them, if i remember right.
     
    BILT4ME likes this.
  4. shocktower

    shocktower

    Messages:
    902
    Likes Received:
    612
    Joined:
    May 20, 2009
    Location:
    Canby Oregon
    So let me get this right, you paid a guy to fix it, and it is now all over the place, I would have turned right around and took it back, and asked WTF dude this is not good
     
    beno likes this.
  5. shocktower

    shocktower

    Messages:
    902
    Likes Received:
    612
    Joined:
    May 20, 2009
    Location:
    Canby Oregon
    Really go back and recheck work he just paid for BS, you pay a pro you don't recheck his work SMFH. Learn how to do it yourself then you don't have to check on the other guy :meh::meh::meh::meh::meh::meh::meh:
     
    Qball and sea bass like this.
  6. nukegoat

    nukegoat

    Messages:
    2,250
    Likes Received:
    1,748
    Joined:
    Apr 11, 2013
    Location:
    San Jose, CA
    I really hope your sai isnt 20 degrees
     
  7. Rifleman

    Rifleman

    Messages:
    1,002
    Likes Received:
    527
    Joined:
    Feb 4, 2015
    Don't flame me, the OP ask for ideas of what could be the possible causes of his problems. If he decides to repair it himself even after he's already paid for the job, or take it back to the shop is up to him. All i can say, if i found that those nuts or wheel bearings were left lose. I'm not so sure I'd want that shop turning anymore wrench's on my truck, even if they do make things right. YMMV
     
    NLXTACY, Malleus and Qball like this.
  8. Qball

    Qball

    Messages:
    3,409
    Likes Received:
    2,024
    Joined:
    Jul 26, 2012
    Location:
    SoCal

    I have paid people to work on my LC and other cars, there are few times that they failed miserably I either fixed it myself or took it to somewhere else. I agree, they they really jacked it up the first time then they will most likely to do it again.
     
  9. gummycarbs

    gummycarbs

    Messages:
    272
    Likes Received:
    173
    Joined:
    Apr 14, 2016
    Location:
    Oregon
    Having a second shop inspect it gives you a record of what was done wrong. Gives Judge Judy a solid reference point.
     
    shocktower likes this.
  10. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    My mechanic is a lead technicians at a local cruiser shop, and I personally know him. To make some $$ on the side, he works on quite a few cruisers at his house as he has a lift and all the tools needed to do a job more efficiently. I was in a rush and this would have been my first time, so that's why I had him do it. In hindsight, wish I did it myself... oh well.

    I had taken him all the parts, including 85-90 diff oil, however, he ended up filling it with 85-140 Castrol gear oil, as he had a drum/dispense nozzle with him. Could in any way the thicker oil be an issue??
     
  11. Rifleman

    Rifleman

    Messages:
    1,002
    Likes Received:
    527
    Joined:
    Feb 4, 2015
    Quick answer, NO.
     
  12. midfat

    midfat

    Messages:
    635
    Likes Received:
    949
    Joined:
    Mar 25, 2013
    Location:
    Santa Monica, CA
    My results for comparison...
    [​IMG]
     
  13. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    I spoke to the mechanic just now, and he verified that he tightened the inner 52mm locknut to 44 ft/lbs and the outer locking one to 65 ft/lbs. I have also been reading up on this more and found the following link:

    Front axle rebuild torque specs

    Post #4 of this discussion basically says the following:

    1) Tighten inner lock nut to 43 ft/lbs. Rotate hub each way a few times
    2) Loosen inner lock nut.
    3) Retighten inner lock nut 2.9-5 ft/lbs.
    4) Measure revolving weight using a hub bolt.
    5) Lock adjusting nut with lock washer.
    6) Tighten outer 52mm lock nut 58-72 fl/lbs.

    If this is correct, my inner locknut is way too tight right? Could this have already caused premature failure/wear to my brand new wheel bearings?

    When I asked my mechanic about it, he swears he has worked on dozens of cruisers for over ten years, using 44 ft/lbs on the inner locknut, and that 5 ft/lbs isn’t even close to what the torque should be (he said a tighter bearing is better than a looser one, and that it could fail at such a low torque). I’m going back to his house this evening to have him drive it, and I’m also taking the soft copy of the FSM I have.

    Can you guys please verify the correct torque for the inner locknut, cause if it is anywhere near 5, I'm sure he will say he won't take responsibility for putting it together back like that. Thanks for all the help guys!
     
  14. mudgudgeon

    mudgudgeon

    Messages:
    1,770
    Likes Received:
    897
    Joined:
    Dec 17, 2007
    Location:
    Sydney, Australia
    Do some more reading.

    The FSM method is unreliable IM

    There's two schools of thought on this.
    1 - follow FSM ( with standard tires, you might be fine)
    2 - torque inner nut to 20-30ft/lb, and outer to 45ft/lb.

    45ft/lb on the inner is tighter than most would go, but I suspect it will be fine. Highly unlikely any damage was done.

    It's maybe a 20 min job per side to re-torque wheel bearings for me. Probably less for a pro
     
    BILT4ME likes this.
  15. BILT4ME

    BILT4ME

    Messages:
    3,740
    Media:
    3
    Albums:
    2
    Likes Received:
    3,007
    Joined:
    Nov 9, 2012
    Location:
    Olathe, KS, USA
    What @mudgudgeon stated is correct.

    If your SAI is what their machine says, then you probably have trunnions bearing issues and or your steering arms are not correctly set.

    Look at @nukegoat s numbers. Wat different.
     
  16. gummycarbs

    gummycarbs

    Messages:
    272
    Likes Received:
    173
    Joined:
    Apr 14, 2016
    Location:
    Oregon
    Oh, boy, you just opened a can of worms.

    My 94 FSM says that the lock nut should be torqued to 47 ft-lb, not the 58-72 you listed.
     
  17. BILT4ME

    BILT4ME

    Messages:
    3,740
    Media:
    3
    Albums:
    2
    Likes Received:
    3,007
    Joined:
    Nov 9, 2012
    Location:
    Olathe, KS, USA
    I also think there's a lb-in rating in there somewhere and not a lb-ft as stated.
     
  18. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    I'm not too worried about the torque of the outer locknut... it probably could be in the 50 ft-lb range. I would assume that the torque of the inner one (adjusting nut) is what matters, as it governs how tight the bearings are being held.
     
  19. ReformedJeeper

    ReformedJeeper

    Messages:
    393
    Media:
    5
    Albums:
    1
    Likes Received:
    150
    Joined:
    Nov 18, 2014
    Location:
    Anaheim, CA
    Your problem isn't due to wheel bearings, the symptoms don't make sense. You said it's twitchy, not vibrating or grrring. Your Steering Axis Inclination (SAI) is horrible. IMO this indicates that something is not seated properly on your steering arms or you have trunion bearing issues (did he change the trunion bearings? If not, any chance he mixed up which ones went on the left/right or upper/lower? Did he put in a new bearing without changing the race )

    Look for a gap between your steering arm and knuckle. As others have stated, check for loose knuckle bolts. Also, make sure your tie rod ends are properly seated in the steering arms.

    Your SAI is extremely jacked up, start looking for what causes that.

    My personal guess is the arms aren't seated all the way.
     
  20. Lankan

    Lankan

    Messages:
    125
    Likes Received:
    31
    Joined:
    Oct 2, 2014
    Location:
    Simi Valley, CA
    Yes, the trunion bearings were changed. I was unaware that they were side and placement (top/bottom) specific. I will check with the mechanic tomorrow morning about that and if he changed out the race.

    l re-visited my mechanic this evening and checked/did the following:

    1) No gaps between the steering arm and knuckle.
    2) Knuckle bolts were tight.
    3) Tie rod ends are properly seated in the steering arms.
    4) Loosened, and re-torqued the 52mm inner nut to 100 in/lbs (@8 ft/lbs). This did not have any positive/negative effect on the drive home.

    During the inspection, we did notice that one of my lower front trailing arms (passenger side) is bowed inwards. I think this was caused by a un-tightened trailing arm to chassis bolt (the rear one) on the drivers side. This was discovered this weekend during the knuckle rebuild, but it had been loose for a few months, which caused it to have slight movement during acceleration and braking. My theory is that this transferred excessive force onto the "fixed" front passenger side trailing arm, causing it to bend over time. In addition to all this, most if not all six front trailing arm bushings are cracked pretty badly.

    What I don't understand is, why all this came to light after the knuckle rebuild, and how in the world did the alignment place (firestone) say that there was nothing wrong!! I think I will start with getting a new control arm and installing new bushings on both arms (maybe even look for a used set with good bushings).