63-82 Rear Trailing Arm Rebuilding Part 2
Next look at your spindles. If you have threads like this replace the spindle. The spindles are axles so don't get confused by people's terminology. When you get the axle out look to see if the outer bearing is still pressed on. If so that's very good but if it moved or came off the axle is most likely undersize OR someone slip fit them- mistake GM did that in early 63 and the bearings spun, got very hot and snapped the axles. Those were drum brake cars and the wheel would just come off. Look to make sure the splines are not twisted, the good GM axles usually last with 400-450hp but enough abuse will break them.DO NOT go cheap and buy imports arms or axles, they are junk.
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Ok on to Bearings. I use only Timkens and CR/SKF seals. I could debate the fact other bearings are just as good or Timken are not made here anymore. You decide what you want. You can save $20 using imported bearings if you want. The Timkens I have are still stamped USA and I'll pay more for them.
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The book calls for .001-.008 endplay in the bearings. I set them to .0015 -.002 +/- .0003" That is correct 3 tenths. Others may tell you otherwise which is ok for them, remember this is how I do them.
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Here is the fixture I made to setup the endplay
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Now here is the deal on this job. IF you want the BEST job done use a surface grinder to dial in the endplay. If a guy tells you he can dial in .002 endplay with just the common shim kits - walk away. I have never had one shim I could use without grinding it to size. Also, you see those kits with the new spacers in them, total waste of your money. Unless the original spacer was burnt by an idiot with a torch they are still good and they do not fail in service. The thing with them is they are not parallel finished. I always parallel grind them before even setting them up in the fixture. It is not uncommon to find them out .005 or more. This can change the endplay you setup on the setup tool to the final press on install. The amount of damage on the spacer faces will determine just how much I have to clean up before I can reuse them. Sometimes the large diameter is beat up pretty bad and once cleaned up the spacer is no good because the inside angle where it is tapered will hit the shoulder on the setup tool or spindle. This is important, if you miss it you will never dial in the endplay and the reading you get will be false. Once on the spindle or setup tool there should be no gap under the spacer, if you can slip a 001 shim in there then it's all done and you will need a new one with the full counter bore end.
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OK with the spacers ground and in the fixture. I use a large shim to start. I have one that I use as a setup shim. I torque the tool to 100 ft/lbs and see how much endplay I have. Then grind a new shim to size and double check it. I only use light spindle oil on the bearings- no grease until you are done and ready to install the bearing in the press.
Use a micrometer over a dial caliper for this job. If your guy thinks a mic is a C clamp - walk away. Or even better as reported in a leading corvette magazine- "so and so has been rebuilding rear bearings for so long, he can feel the correct endplay"
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When the endplay is set I install the prepped and painted parts on the arm.
It is much easier to install the parking shoes with the spindle out of the way.
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Now before you install the spindle you have to remove the outer bearing. This should be done before you get to this point. Remove the bearing, clean the spindle, check the journals, replace the studs and I face the flange in a lathe as well.
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Now if the threads are rolled a little you may be able to save them. I have a thread forming tool, thread file, lathe, but you can use the "old school way" of using an old nut and some very fine lapping compound to clean them up. BE sure the threads are good and you use a new nut before you get to the bearings.
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Next look at your spindles. If you have threads like this replace the spindle. The spindles are axles so don't get confused by people's terminology. When you get the axle out look to see if the outer bearing is still pressed on. If so that's very good but if it moved or came off the axle is most likely undersize OR someone slip fit them- mistake GM did that in early 63 and the bearings spun, got very hot and snapped the axles. Those were drum brake cars and the wheel would just come off. Look to make sure the splines are not twisted, the good GM axles usually last with 400-450hp but enough abuse will break them.DO NOT go cheap and buy imports arms or axles, they are junk.
Ok on to Bearings. I use only Timkens and CR/SKF seals. I could debate the fact other bearings are just as good or Timken are not made here anymore. You decide what you want. You can save $20 using imported bearings if you want. The Timkens I have are still stamped USA and I'll pay more for them.
The book calls for .001-.008 endplay in the bearings. I set them to .0015 -.002 +/- .0003" That is correct 3 tenths. Others may tell you otherwise which is ok for them, remember this is how I do them.
Here is the fixture I made to setup the endplay
Now here is the deal on this job. IF you want the BEST job done use a surface grinder to dial in the endplay. If a guy tells you he can dial in .002 endplay with just the common shim kits - walk away. I have never had one shim I could use without grinding it to size. Also, you see those kits with the new spacers in them, total waste of your money. Unless the original spacer was burnt by an idiot with a torch they are still good and they do not fail in service. The thing with them is they are not parallel finished. I always parallel grind them before even setting them up in the fixture. It is not uncommon to find them out .005 or more. This can change the endplay you setup on the setup tool to the final press on install. The amount of damage on the spacer faces will determine just how much I have to clean up before I can reuse them. Sometimes the large diameter is beat up pretty bad and once cleaned up the spacer is no good because the inside angle where it is tapered will hit the shoulder on the setup tool or spindle. This is important, if you miss it you will never dial in the endplay and the reading you get will be false. Once on the spindle or setup tool there should be no gap under the spacer, if you can slip a 001 shim in there then it's all done and you will need a new one with the full counter bore end.
OK with the spacers ground and in the fixture. I use a large shim to start. I have one that I use as a setup shim. I torque the tool to 100 ft/lbs and see how much endplay I have. Then grind a new shim to size and double check it. I only use light spindle oil on the bearings- no grease until you are done and ready to install the bearing in the press.
Use a micrometer over a dial caliper for this job. If your guy thinks a mic is a C clamp - walk away. Or even better as reported in a leading corvette magazine- "so and so has been rebuilding rear bearings for so long, he can feel the correct endplay"
When the endplay is set I install the prepped and painted parts on the arm.
It is much easier to install the parking shoes with the spindle out of the way.
Now before you install the spindle you have to remove the outer bearing. This should be done before you get to this point. Remove the bearing, clean the spindle, check the journals, replace the studs and I face the flange in a lathe as well.
Now if the threads are rolled a little you may be able to save them. I have a thread forming tool, thread file, lathe, but you can use the "old school way" of using an old nut and some very fine lapping compound to clean them up. BE sure the threads are good and you use a new nut before you get to the bearings.
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