just rebuilt my rear axle

96BroncoMan

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Joined
Sep 7, 2005
Location
Charlotte/Raliegh
I just rebuilt my rear axle, and now i have a few questions. When i rebuilt it, it was within all the specs, then, i bolted it all up and its HARD to turn the pinion, way tighter thah the specs said b4 it was all bolted up. could it be due to the wieght of the ARB?? i had to slightly spread the diff with a homebuilt spreader, then put in an extra .007 shim on each side, to make sure when the spreader was removed i had the proper carrier perload, since i dont have a method to measure that. i thought that alot of ppl who do work like this in their home garage dont have a carrier preload checker. i dunno, i just wanted to know to make sure i didnt have to redo anything before i went ahead with the install under the truck. thanks.
 
do you have access to an in-lb torque wrench? that is how most people would check to see the preload? or possibly i am not understanding exactly which parameter you are talking about>?
 
the pinion bearing preload was supposed to be between 16 and 29in-lbs, and it measured 23in-lbs before i put the everything together for the final time. Now, the preload is WAY high, i can barely turn it by grabbing it with my hands, its clearly higher, but only after the case spreader was moved. and i was wondering if it could be caused by the pressure on the carrier now that the spreader was removed, like when i added the .007 shim on each side, its too tight with the spreader removed...just curious if its okay or not.
 
The preload will be tighter with the carrier installed, because the carrier also has preload which adds to the required rotating force of the assembly. Also the seal adds a little bit of resistance(technically the pinon preload should be measured without the seal)

There is really no way to measure the carrier preload, the pros don't measure it, its more of a feel thing

Also i never use a case spreader, but i would prolly setup the pinion preload without the spreader installed.
 
Barely

Do you really mean barely? Pretty tight isn't necessarily bad. Like both hands trying to open a pickle jar hard?
 
yeah, its alot like trying to open a pickle jar to get the pinon to spin. i guess my question is, could i have put too many shims in the carrier and now it has too much pressure to allow it to spin as easily as it should?? im wondering if the use of the spreader allowed me to put too many shims in, and its squeezing the carrier too much now.
 
When did you discover this? Something I have learned through the years is to check rotating assemblies constantly as you put them together, so that you notice a problem when you put the problem there, not once it's all put together.

Could be insufficient shims for the pinion, or too many shims for the carrier bearings. Seals shouldn't add a noticeable amount of effort. Another good practice is to put oil on bearings and seals before installing.
 
total preload can be measured by rotating pinion with carrier installed, it sounds like it is to tight take out some carrier shims. you want the carrier to be tighter than if your checking backlash you should not be able to push it easily back and forth w/ your finger but should have to grab ring gear and move it back and forth easy. if your having trouble moving ring gear w/ hand its to tight. Also if you can't pry the carrier out with out using spreader its probably to tight. with 2 pry bars you should be able to pop it out. Whats your backlash all bolted up. your pinion should be easy to turn back and forth a smidge and then get a little stiffer as ring gear engages.
 
96BroncoMan said:
yeah, its alot like trying to open a pickle jar to get the pinon to spin. i guess my question is, could i have put too many shims in the carrier and now it has too much pressure to allow it to spin as easily as it should?? im wondering if the use of the spreader allowed me to put too many shims in, and its squeezing the carrier too much now.
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You could have too much preload on the carrier bearings from your spreader. I have never used a spreader either. Put a wrench on one of your ring gear bolts and just move it enough back and forth to touch the pinion. You could probably tell if it is very hard to turn or not. Do the same thing with the pinion. Hold the yoke with your hand an turn it back and forth against the ring gear. I know you won't have but .008-.010 of play, but it might give you an idea. I would suggest pulling the carrier back out, taking the spreader off, and checking preload again. You don't need a spreader to put your case back in. Start with the factory shim first, to get a starting point for preload. Most of the time it is really close. You will need a good deadblow hammer or a big piece of brass and a sledge.
 
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