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Technical 9" Ford Back Truss

Discussion in 'Traditional Hot Rods' started by FNG, Mar 12, 2021.

  1. FNG
    Joined: Jan 22, 2006
    Posts: 422

    FNG
    Member
    from New Jersey
    1. HAMB Relays

    Has anyone installed a truss or brace on the back of their 9" Ford axle? From what I have read on the good old innerweb its recommended if your planning on 500hp or better to prevent the axle from twisting. I've watched the videos and they claim the rear can flext up to an 1/8" or more when welding. So I was wondering if anyone has any experience in welding one of these in. I was thinking about taking it in to place before removing the entire axle or maybe I should just remove it and secure it to the welding table and have at it.
    Your thoughts are always appreciated
    Thanks for looking
     
  2. lippy
    Joined: Sep 27, 2006
    Posts: 6,091

    lippy
    Member
    from Ks

    Is this a flathead ford in front of this axle?
     
    Happydaze and Texas Webb like this.
  3. :D
     
  4. Marty Vanin
    Joined: Feb 22, 2017
    Posts: 69

    Marty Vanin
    Member

    A lot of guys with more than 500HP racing without a braced
    housing.
     
    egads likes this.

  5. You should actually straighten the housing before starting. Then leave the straightening jig in place when you weld it or it can warp it back untrue and you will never get it straight. I am running a 9" behind a 750+ HP OT drag car and it is not braced
     
    FNG, egads and loudbang like this.
  6. Not all Ford 9" housings are the same, it depends on which housing you have, the installation, and intended use to determine whether or not a brace is needed.
     
    seb fontana, Hnstray and loudbang like this.
  7. lostone
    Joined: Oct 13, 2013
    Posts: 1,997

    lostone
    Member
    from kansas

    Yeah i've done a couple. Built my own braces out of thin wall rec tube.

    Made a pattern of the rear end contour and the length I wanted it to be. Drew it out on the floor, split my rec tube in the middle and a pie cut there, then close up the pie cut until the back side of the rec tube matched the angle of my pattern.

    Once I have it matched to the pattern I weld it solid and grind and smooth the weld out. Then I lay the pattern on top and draw out the axle contour, turn it over and do the same on the other side of the tube.

    Cut it out top and bottom and there you go. All ready to weld on.
     
    loudbang likes this.
  8. cktasto
    Joined: May 31, 2009
    Posts: 312

    cktasto
    Member

    Looking to do same with mine. Some different approaches shown you tube videos, some are good examples of what not to do


    Sent from my iPhone using H.A.M.B.
     
    FNG and seb fontana like this.
  9. Just do it and you won't have to think about it again, the new fabricated housings are braced on the inside so you don't need an outside brace, just food for thought.

    20210312_232044.jpg
     
    Tman, FNG, 1940Willys and 3 others like this.
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 50,884

    squirrel
    Member

    I was staring at my cracked 57 9" housing, and wondering how to weld a brace on it, without distorting the housing all to hell from the heat/cooling of the long welds along the tubes. After a while I figured it out...the truss gets it's strength from the strap that goes from the center, to the ends. The "web" part does not do much at all. So...I left off the web, and just added the strap. Very little welding to attach the truss. It seems to work. Somewhere in the 600-700 hp range, the car's been in the 9s.

    rear brace.jpg
     
    Last edited: Mar 12, 2021
    silent rick, Tman, fauj and 6 others like this.
  11. What size line do you have going through that metal fuel filter Jim ?
     
  12. squirrel
    Joined: Sep 23, 2004
    Posts: 50,884

    squirrel
    Member

    it's a 1/2" filter, Wix 33299, with 1/2" metal tube running to the front of the car, and -8 AN fittings and hose in several places.
     
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  13. Thanks, I didn't realize they made one that size, I need a pre filter to my regular filter on the J since it's been sitting for the last few years.
     
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  14. squirrel
    Joined: Sep 23, 2004
    Posts: 50,884

    squirrel
    Member

    fits 30 year old GM motorhomes.
     
    Tman likes this.
  15. I just ordered a couple off amazon, I'm going to stick a borescope in the tank to see what it's like, hopefully no crazy rust build up, if not bad then I'll run a couple tanks of fuel through them before going straight to the Mallory filter under there. Thanks for the part #
     
  16. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,056

    MeanGene427
    Member
    from Napa

    There are many race cars running an unbraced 9" housing, even seen some Galaxies running 10's, probably on the ragged edge. The later housings were beefed in that area from the factory ( I have a 31 spline 66 428 Bird setup in my 406 car, same width, but much beefier housing). A simple strap would be a lot better than nothing, but I can't agree that the webbing does nothing, and the folks who build fab housings seem to agree. There is always a degree of twisting force involved, both sides are not loaded the same, as shown by peg-legging etc. More power dictates more strength, and shorter housings are naturally more stiff. I have three 48' wide units, a 40 spline Strange, 40 spline Mark Williams, and a 35 spline Strange, and all have fully webbed bracing. I just remembered when I was a kid in Southern Tier NY, my gramps had an ag lime spreading outfit, and there was a lot of call to get on the fields during snowmelt, so he got three M35 deuce and a halfs. They worked very well, and were regularly loaded to 11 tons, quite a bit past the (conservative) 2-1/2 ton rating. So one day during his walk- around, my uncle noticed a puddle under the back axle of one, and discovered a crack in the housing. These trucks have the third members that drop in from the top, not the front. It was taken to a very talented old-time welder, with a good imagination. He made up a jig setup to check for square off the machined axle flanges on the hubs, and it was settled of course. Using three jacks, he worked it back square, then welded the crack, and then bent up a 4" wide strap of 1/2" plate that followed the housing, and started welding it in, a couple inches at a time, one side then the other, then stopped to square, and adjusting it with the three jacks- all underneath the truck, without removing the housing. Came out dead nuts, so he got the job to do all six rear housings
     
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  17. squirrel
    Joined: Sep 23, 2004
    Posts: 50,884

    squirrel
    Member

    Why make all that extra work for yourself?

    Keep in mind that this is the HAMB, and I don't recall seeing fully welded back braces on race cars in the 60s.
     
    Tman likes this.
  18. DDDenny
    Joined: Feb 6, 2015
    Posts: 16,059

    DDDenny
    Member
    from oregon

    Not easy to find nowadays but these don't need a back brace.
    20170326_094304.jpg 20161216_123917.jpg
     
    kidcampbell71 likes this.
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 50,884

    squirrel
    Member

    I really need an Olds rear end....
     
    Just Gary likes this.
  20. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,056

    MeanGene427
    Member
    from Napa

    Do as you like with yours- but if you are running pretty good power through that early 57 housing, that has already cracked, and you have only dealt with strength in one linear direction, sooner or later it will stress out again. If it was one of the later housings, the center area where the tubes meet the center are much beefier than the early ones where they stress. I have done several with the early 57-59 narrow housings without beefing them, but only small block cars with autos. Worrying about if it was done that way in the 60's is a non-factor for me when a potential safety issue is concerned- if the housing breaks, you will go for a ride
     
  21. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,056

    MeanGene427
    Member
    from Napa

    See how beefy that is near the pumpkin, compared to the 57 Ford housing? The later 9" housings are like that, much improved and stronger than the 57-64 9" housings. Nice looking setup, very clean
     
  22. DDDenny
    Joined: Feb 6, 2015
    Posts: 16,059

    DDDenny
    Member
    from oregon

    Not if it was a 57 F100 housing like mine.
    See post #18.
     
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  23. Budget36
    Joined: Nov 29, 2014
    Posts: 8,369

    Budget36
    ALLIANCE MEMBER

    Educate me, this keeps the axles from moving "forward"?

    I've seen AM 9 inch housings all triangulated up and such, has me curious, especially on @squirrel s strap?

    Not that I need it, just wondering:)
     
  24. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,056

    MeanGene427
    Member
    from Napa

    Never used an early pickup 9", do they have the car-type outer bearings? The later pickup stuff with the outer tapered rollers is beefy, but you need new ends
     
  25. DDDenny
    Joined: Feb 6, 2015
    Posts: 16,059

    DDDenny
    Member
    from oregon

    Not positive on the dimensions of F100 bearing ends compared to passenger car housing ends but yes, same style, I removed the original ends when housing was modified, it now has billet aftermarket ends.
    Not sure if you are aware but these housings are half ton only, 1957 only.
    I'm not clear as to the mfg process but these don't have weld-on axle tubes, they are also known to have the thickest material in the axle tube area which is why they were so popular with drag racers.
    Here is a shot of the housing from above.

    20170404_125649.jpg
     
    Last edited: Mar 13, 2021
  26. jaracer
    Joined: Oct 4, 2008
    Posts: 1,462

    jaracer
    Member

    When I got my 57 T-Bird, it had a brace that ran under the housing. It was a bent piece of round stock and it was held to the axle housing near the spring perches with a clamps much like a muffler clamp. It looked like it was a bought piece, not homemade. I took it off when I installed a rear sway bar setup that went in the same space. Tried to sell it at the swap meet. I even told a couple of lookers that it might have been on one of Foyt's stock cars. It's still in the back of the shop somewhere.
     
  27. DDDenny
    Joined: Feb 6, 2015
    Posts: 16,059

    DDDenny
    Member
    from oregon

    Scappoose is a long way from Houston, in fact Scappoose is a long way from anywhere!:p
     
  28. Budget36
    Joined: Nov 29, 2014
    Posts: 8,369

    Budget36
    ALLIANCE MEMBER

    You Scapoose so?
     
  29. Marty Strode
    Joined: Apr 28, 2011
    Posts: 6,700

    Marty Strode
    Member

    They take the same bearing as large passenger (wagon).
     
  30. sdluck
    Joined: Sep 19, 2006
    Posts: 2,879

    sdluck
    Member

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