I am rebuilding a front disc brake axle from a parted out 1980 40 to put on my 82 45LPB. All new parts, bearings, races, seals, etc.
I have been following the disassembly and reassembly of a 40 axle on the 40Channel:
At the 21 minute mark of the video, after checking preload and finding it too loose, he removes a shim from the bottom of the knuckle and the preload tightens up within spec which he says should be between "3-6 kg."
On my axle, after reassembly using the old shims that were in place, the preload was very loose, almost zero, so following the video I removed the only shim that was on the bottom of the knuckle, and as in the video the preload tightened up, just under 6 kg using a luggage scale. I measured in kg because that was the reference in the video.
I then finished assembling that side of the axle and the preload is 6 kg but feels "tight." Having never done this before I dont know if that is how it should feel. I then read through many threads here on Mud which say that the bottom shims should not be used to set preload, only to center the knuckle and all preload adjustments should be done through the top shims under the steering arm.
The threads on Mud also mention that preload before final assembly should be "around 5 lbs" but I have also seen references to "between 4 and 11 pounds" which I believe is much lower than the "3-6 kg" in the 40Channel video.
Couple of questions: at this point, should I put the bottom shim back on the knuckle? Can I adjust preload by removing shims from the top without disassembling the whole knuckle again or do I have to disassemble everything again? What should the preload be in pounds?
I do not have the factory centering tool and did not attempt to center the knuckle, I intended to use the shims that were in place before the rebuild but the preload was too low (under 1 kg on the scale). I did not measure preload before I disassembled the axle, but I saw several threads suggest that you should simply put the axle back together with the shims that were in place before disassembly. I did that but the preload was almost zero so I dont think that is an option.
Any help offered is greatly appreciated.
I have been following the disassembly and reassembly of a 40 axle on the 40Channel:
At the 21 minute mark of the video, after checking preload and finding it too loose, he removes a shim from the bottom of the knuckle and the preload tightens up within spec which he says should be between "3-6 kg."
On my axle, after reassembly using the old shims that were in place, the preload was very loose, almost zero, so following the video I removed the only shim that was on the bottom of the knuckle, and as in the video the preload tightened up, just under 6 kg using a luggage scale. I measured in kg because that was the reference in the video.
I then finished assembling that side of the axle and the preload is 6 kg but feels "tight." Having never done this before I dont know if that is how it should feel. I then read through many threads here on Mud which say that the bottom shims should not be used to set preload, only to center the knuckle and all preload adjustments should be done through the top shims under the steering arm.
The threads on Mud also mention that preload before final assembly should be "around 5 lbs" but I have also seen references to "between 4 and 11 pounds" which I believe is much lower than the "3-6 kg" in the 40Channel video.
Couple of questions: at this point, should I put the bottom shim back on the knuckle? Can I adjust preload by removing shims from the top without disassembling the whole knuckle again or do I have to disassemble everything again? What should the preload be in pounds?
I do not have the factory centering tool and did not attempt to center the knuckle, I intended to use the shims that were in place before the rebuild but the preload was too low (under 1 kg on the scale). I did not measure preload before I disassembled the axle, but I saw several threads suggest that you should simply put the axle back together with the shims that were in place before disassembly. I did that but the preload was almost zero so I dont think that is an option.
Any help offered is greatly appreciated.
