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Straightening a rear end housing

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  • Straightening a rear end housing

    Some of the sheetmetal fabricated rearend housings I buy are tweaked when I get them. What is the correct way to bring them back to true. Heat and cooling , big press ?

    Both axles tubes are pulled towards the rear by about 1/8-1/4 inch at the ends of a 40" wide housing.

    I have access to different types of torches, etc...

    I'm assuming it was heat that pulled it out of true during construction, and I would need to apply heat to the other side to bring it back.

    Thanks for the replies and help.

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  • #2
    1320 fabricator,
    My advise would be to contact the manufacturer first they may have a production problem that needs addressing. Second I would heat it as little as possible to make it pliable and don't straightn it with brute force like a hammer. I would Jig it up and put chains from the ends attached to a beam and draw it out with a hydraulic jack, sloooooly pull it into true, but remember it will pull back some so you have to go a little past where you want it to end up.

    This is delicate work, be cautious and good luck.


    • #3
      I have seen some pretty butchered rear end jobs. It is not really that difficult to weld/repair/fab etc. In order to repair small differences like 1/4" or 1/8", I would put the main body in a vise, or clamped to a table. Level the main body in two directions. Then put your level on one of the legs. With an o/a torch, with a small flame, heat a small spot close to the main body and on the side you want the leg to move to. When the spot is cherry red quench it with a wet rag. When you quench it the metal will shrink causing the leg to move in that direction. Just try small spots, as it will move more than you think.


      • #4
        This is common on any rear end if it had any welding done on it. On all the rear ends I build, I straighten with a torch and dial indicators. Every time I weld on caliper brackets or shock mounts, I have to restraighten or for all the circle track stuff we do, we actually will camber the rear slightly also. When you heat the tube, it will go the opposite way and when it cools, it will come back further than when you started. I do this with bearings, hubs and rotors in place and tight.(no grease or seals) I take my readings off the rotor faces.

        Good luck.