Straightening a rear end housing
(→Heating and bending) |
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==Building a straightening table== | ==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 | + | 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.]] | [[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 | + | 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. | 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. | ||
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[[Image:Making_inserts_in_lathe.jpg|frame|none|Making the inserts in a lathe.]] | [[Image:Making_inserts_in_lathe.jpg|frame|none|Making the inserts in a lathe.]] | ||
| − | Another insert was made with the same 1.504" ID | + | 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 | + | 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.]] | [[Image:Straight_bar_in_inserts.jpg|frame|none|The straight bar, in the inserts.]] | ||
==Measuring== | ==Measuring== | ||
| − | The housing end insert slides over the bar | + | 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.]] | [[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 | + | 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.]] | [[Image:Finding_housing_bend.jpg|frame|none|A ruler is used to see where the tube is bent.]] | ||
==Heating and bending== | ==Heating and bending== | ||
| − | Next, rig a chain at the point of bend | + | Next, rig a chain at the point of bend and put a 12-ton bottle jack under the end of the axle. To prevent bending the center casing, attach the rear cover. You can try to bend the axle tube at this point, without heat. If you want to bend the tube in this way, push the tube approximately 5 times the amount you want it bent. In other words, if your alignment is off by .030" , you need to push the end of the tube about .150" or more to overcome springback. If your axle housing end is off by more than .100" from the alignment jig, you will probably need some heat. |
[[Image:Bottle_jack_and_chain.jpg|frame|none|A bottle jack and chain are used for bending.]] | [[Image:Bottle_jack_and_chain.jpg|frame|none|A bottle jack and chain are used for bending.]] | ||
| − | If you find that you need to heat the axle tube, jack up the housing into perfect alignment with the housing end insert | + | If you find that you need to heat the axle tube, jack up the housing into perfect alignment with the housing end insert and heat a band all the way around the tube until it's red-hot. Let the tube cool while it's still supported by the jack. |
[[Image:Heating_the_axle_tube.jpg|frame|none|Heat a band all the way around the tube.]] | [[Image:Heating_the_axle_tube.jpg|frame|none|Heat a band all the way around the tube.]] | ||
[[Image:Red_hot_band.jpg|frame|none|A red-hot band indicating proper and even heating of the tube.]] | [[Image:Red_hot_band.jpg|frame|none|A red-hot band indicating proper and even heating of the tube.]] | ||
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