Editing Straightening a rear end housing

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Here's how to make a fixture and rack for straightening a rear end housing.

==Building a straightening table==
The straightening fixture pictured below is an old gas cylinder cart, bought at a garage sale and the top cut off.  A 6" X 6"  I-beam was then welded to the  cart. You don't need a cart, any sturdy legs will do. This cart just happened to be handy and had nice wheels so we could wheel it around the shop.
[[Image:Axle_straightening_table.jpg|frame|none|A gas cylinder cart, converted for straightening rear end housings.]]

To prevent any mishaps involving slippage and gravity, common jackstands are cut up to wrap the leg of the I-beam. The bottoms were notched and a slice made at each corner to get the stands fitted  to the I beam.[[Image:Modified_jackstands.jpg|frame|none|Basic inexpensive jackstands are modified to wrap the I-beam for stability.]]

A straight bar is necessary. This hardened and chrome-plated bar is about five feet long, and 1.5" in diameter. It's available from McMaster-Carr for about $115.00. Alternatively, an old length of scrap steel shafting can be used. V-blocks and a dial indicator can be used to verify that a used bar is straight. Smooth, round and straight is best. You could use 1" round bar but the accuracy will suffer. One of the manufacturers that sells these alignment fixtures uses 1 11/16" bar. Bigger than 1 3/4" and the bar will be too big to handle.
[[Image:Hardened_bar.jpg|frame|none|A hardened and chrome plated steel bar.]]

==Making the inserts==
Then, make some inserts. These are about 2" long, as to provide some load bearing area to lessen wear caused by repeated use. For this application (10-bolt Chevrolet), the ID is 1.504", and the OD is 2.894". These same size inserts will work in an 8" and 9" ford center sections as well.
[[Image:Making_inserts_in_lathe.jpg|frame|none|Making the inserts in a lathe.]]

Another insert was made with the same 1.504" ID and dimensioned to slip-fit into the housing end. This same set of inserts and matching bar can be used as an alignment aid when narrowing rear end housings.

The inserts are then clamped in the bearing saddles and the bar slides through them. The fit should be nice -- the bar should slide through easily, but with no noticeable play.
[[Image:Straight_bar_in_inserts.jpg|frame|none|The straight bar, in the inserts.]]

Here is the inserts installed in a Ford 9" center section, the bar is slid through before the bearing caps are tightened, to make sure they are aligned in the bearing saddles.

[[Image:PICT0040.JPG|frame|none|9" Ford center section with inserts and bar.]]

Another way to determine if the housing is straight is to machine the inserts for the diff center with a small center hole, clamp these in and install centre in housing.Then usng a sheet of paper with a small hole held at the bearing end site through and line up with two holes that are in the center then run your finger around the tube end marking the paper. find the center of you mark and this will show you how far your diff is out by comparing the hole in the paper to the center.

==Measuring==
The housing end insert slides over the bar and indicates how much the end of the housing is bent out of alignment.
[[Image:Housing_end_insert_slid_over_bar.jpg|frame|none|The housing end insert is used to indicate the alignment of the housing.]]

Hold a ruler on the tube to see where it's bent. In this case, it's bent at the areas that were welded by the previous "builder".
[[Image:Finding_housing_bend.jpg|frame|none|A ruler is used to see where the tube is bent.]]