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Straighten A Bent 9" Ford Rear End Housing:

Discussion in 'The Hokey Ass Message Board' started by Drive Em, Aug 30, 2009.

  1. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    Here is a small pictorial on how I straighten 9" Ford rear end housings. This method will work on any rear end housing. Nine out of ten housings that I work on will require straightening on at least one axle tube. A bent housing will cause uneven tire wear, ill handling and possible bearing failure. Most of them get tweaked or bent through use over thousands of miles and years of use. They can also get bent in accidents, or through serious welding on the housing. There are other methods used to straighten a housing, but I have used this method hundreds of times with excellent results.

    I use a heavy I-beam as the work surface because there will be several tons of force being applied to it. My fixture consists of a 20 ton Porta-Power, a heavy steel U-strap that bolts to the I-beam and a regular automotive jackstand that has been modified specially for straightening housings.

    I use a housing narrowing jig to determine where and how much the housing is bent. Aluminum mandrels take the place of the differential bearings in a dummy centersection housing:
    [​IMG]

    After the dummy centersection is bolted to the rear end housing, this 1 1/2" stainless steel bar slides through the axle tube and through the aluminum mandrels. This gives us an accurate centerline to determine which tube is bent:
    [​IMG]

    The end of the housing that will be straightened is supported with the Porta-Power. The red U-strap is attached to a fixture that is bolted to the I-beam. The U-strap has a removeable 1" diameter pin that allows it to be removed easily. The U-strap keeps the rear end housing from moving as pressure is being applied upward from the Porta-Power on the end of the axle tube.
    [​IMG]

    The other end of the housing is supported with the jackstand that has a piece of angle iron welded to it allowing the housing to rotate easily. The jackstand can also slide on the I-beam to accomodate different housing widths. The jackstand is used to provide a height equal to the height of the Porta-Power and support the housing, nothing more:
    [​IMG]

    Our test subject is a late 60's pickup truck housing that looks good with no visible damage, you would think that this housing is straight by looking at it:
    [​IMG]

    Here is the rear end housing on the straightening jig ready for action:
    [​IMG]


    There is an aluminum mandrel that slides on the end of the alignment bar and it registers snuggly in the housing bearing end. If the housing is straight, the mandrel will slide on the alignment bar and will slide right into the housing end. You can plainly see that this housing is bent at least 1/4" from square:
    [​IMG]

    Once it is determined which way the housing is bent, the housing is rotated 180 degrees from the bend and upward pressure is applied with the Porta-Power. The housing is situated with the U-strap as close to the center "pot" of the housing as possible for more leverage. The U-strap keeps the housing from moving up, but the end of the axle tube is free to bend in the opposite direction of the damage:
    [​IMG]

    The housing is tweaked until the mandrel will easily slide into the housing end. The housing can now be turned around to straighten the opposite tube if it needs it:
    [​IMG]
     
    Last edited: Dec 2, 2013
    j-jock likes this.
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 41,075

    squirrel
    Member

    Nice! do you ever run into rearends that have the ends on at an angle, so the flange is not perpendicular to the mandrel? If so what do you do to fix it?
     
  3. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    I haven't run into that yet, but the only way to fix it would be to cut the housing end off and weld it on straight.
     
  4. donut29
    Joined: Mar 6, 2006
    Posts: 1,518

    donut29
    Member
    from canton MI

    How much do you charge to straighten a housing
     
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  5. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    $75.00 for one side, $100.00 for both.
     
  6. Brickster
    Joined: Nov 23, 2003
    Posts: 1,131

    Brickster
    Member

    I assume that's if the housing is delivered empty?
     
  7. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,675

    296 V8
    BANNED
    from Nor~Cal

    Great post , thank you.
     
  8. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    Correct. I am not trying to drum up business either. I do this to every housing that I narrow, or work on, and I feel it is an important part of building a hot rod.
     
  9. Larry T
    Joined: Nov 24, 2004
    Posts: 8,240

    Larry T
    Member

    If a rearend is tweaked (say 1/4") on a rearend you're gonna narrow, do you straighten it first or take care of it when you weld up your housing ends?
    Larry T
     
  10. Woogeroo
    Joined: Dec 29, 2005
    Posts: 994

    Woogeroo
    Member
    from USA

    That was a dang good read... thank you for documenting it and sharing with the rest of the class.

    -W
     
  11. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    I straighten the housings before I narrow them because it is easier to straighten a long housing tube than a short one. After the housing tubes are cut, I will check them and straighten again before the housing ends are welded on.
     
  12. gotra66
    Joined: Apr 24, 2009
    Posts: 181

    gotra66
    Member

    That is a nice jig. I will file this one away for future reference. does that mandrel slide on the end of the steel rod? I am assuming it does to allow for different length axle tubes.
     
  13. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    Correct.
     
  14. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    Bump so it doesn't get lost.
     
  15. newfalconowner
    Joined: Jul 26, 2009
    Posts: 813

    newfalconowner
    Member
    from NS Canada

    thanx, where can you get the mandrels? or what size is needed if i got them machined here
     
  16. Awesome tech!
     
  17. yoyodyne
    Joined: Nov 26, 2008
    Posts: 866

    yoyodyne
    Member

    Very nice fixture - where do you acquire that U-strap? Where can I get one like that?
     
  18. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    I bought some fixtures that was used by an alignment shop to bend the I beam axles from the older trucks, and that U-strap was in with all the fixtures.
     
  19. dirtbag13
    Joined: Jun 16, 2008
    Posts: 2,540

    dirtbag13
    Member

    excellent tech !
     
  20. TagMan
    Joined: Dec 12, 2002
    Posts: 5,747

    TagMan
    ALLIANCE MEMBER

    Very cool - I just gotta make one of these!

    How do you inspect the 1-1/4" diameter steel bar, to make sure it's straight - just rotate it on a couple of v-blocks and check it with a dial indicator?
     
    seb fontana likes this.
  21. Paul
    Joined: Aug 29, 2002
    Posts: 14,116

    Paul
    Editor

    good stuff, thanks for posting!
     
  22. Drive Em
    Joined: Aug 25, 2006
    Posts: 1,748

    Drive Em
    Member

    Correct, it is very rigid and very straight.
     
  23. 65stepside
    Joined: May 26, 2009
    Posts: 128

    65stepside
    Member

    just postin so i can find this later
     
  24. Thanks for posting, great article!!
     
  25. It looks like you could use a rigging shackle to use a the "red strap" on the straightening jig. They look very similar and both are deisigned for heavy loading.
     
  26. dadseh
    Joined: May 13, 2001
    Posts: 528

    dadseh
    Member

    how about just using a big spring shackle U bolt for the strap??
     
  27. SniffnPaint
    Joined: May 22, 2008
    Posts: 434

    SniffnPaint
    Member

    Again, Great post!
     
  28. AHotRod
    Joined: Jul 27, 2001
    Posts: 10,186

    AHotRod
    Member

    Glad I came across this tonight, excellant TECH post, THANK YOU !
     
  29. Cabbage
    Joined: Apr 17, 2006
    Posts: 724

    Cabbage
    Member
    1. S.F.C.C.

    I just picked up 2 nines, thanks for making this easy to understand, great post
     

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