Straighten A Bent 9" Ford Rear End Housing:

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:


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:


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.


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:


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:


Here is the rear end housing on the straightening jig ready for action:



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:


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:


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:

 

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?

 

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.

 

How much do you charge to straighten a housing

 

$75.00 for one side, $100.00 for both.

 

I assume that's if the housing is delivered empty?

 

Great post , thank you.

 

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.

 

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

 

Very cool.

 

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

-W

 

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.

 

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.

 

Correct.

 

Bump so it doesn't get lost.

 

thanx, where can you get the mandrels? or what size is needed if i got them machined here

 

Awesome tech!

 

Very nice fixture - where do you acquire that U-strap? Where can I get one like that?

 

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.

 

excellent tech !

 

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?

 

good stuff, thanks for posting!

 

Correct, it is very rigid and very straight.

 

just postin so i can find this later

 

Thanks for posting, great article!!

 

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.

 

how about just using a big spring shackle U bolt for the strap??

 

Again, Great post!

 

Glad I came across this tonight, excellant TECH post, THANK YOU !

 

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