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Wheel Bearing Replacement - Snowflakes
- Thread starter 30064
- Start date
30064
Mike V. #30064
I'll be sure to let you know how the wiggle test comes out and how the bike feels. Have to travel out of town and won't return until this weekend. Then the front wheel is next...yikes. What a crazy wheel this 78 snowflake is.
Here's a better picture of the syringe, I've been hanging on to this thing since the girls were babys. Came in quite handy
Here's a better picture of the syringe, I've been hanging on to this thing since the girls were babys. Came in quite handy
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darryl cainey
Sir Darby
5 gal pail!
Just a note;
Instead of clamping the wheel in a workmate I put mine on top of a plastic 5 gallon pail, that way the forces are evenly distributed around the wheel.
The pail won't mark the wheel and you are not puting side load on the rim.
Very nice pictures!
Just a note;
Instead of clamping the wheel in a workmate I put mine on top of a plastic 5 gallon pail, that way the forces are evenly distributed around the wheel.
The pail won't mark the wheel and you are not puting side load on the rim.
Very nice pictures!
30064
Mike V. #30064
Darryl,
Good point. I can assure you; knowing what I know now - my procedure would have changed in a few areas. First; I would have the tire and tube unmounted from the wheel knowing the heat that is transferred, and I would have repositioned the wheel as you noted. I was VERY careful during the insertion. Scary procedure. But the Workmate was an excellent tool for inspection, study and preparation. I'm so glad I got past this part of the procedure.
By the way, I welcome all comments and tips, this is not a job for the faint of heart in my opinion but the experience and knowledge gained was priceless. I was sure to take my time and not rush through anything. I now have a firm understanding of this component.
Good point. I can assure you; knowing what I know now - my procedure would have changed in a few areas. First; I would have the tire and tube unmounted from the wheel knowing the heat that is transferred, and I would have repositioned the wheel as you noted. I was VERY careful during the insertion. Scary procedure. But the Workmate was an excellent tool for inspection, study and preparation. I'm so glad I got past this part of the procedure.
By the way, I welcome all comments and tips, this is not a job for the faint of heart in my opinion but the experience and knowledge gained was priceless. I was sure to take my time and not rush through anything. I now have a firm understanding of this component.
crazydrummerdude
advrider.com
Here's another run-through of the procedure; http://www.advrider.com/forums/showthread.php?t=388220
He's a member here under a different, but similar name..
He's a member here under a different, but similar name..
Congratulations! Let me add a side note then.
At the factory, on the assembly line for wheels - the bearing assembly went as follows. I witnessed this on an English language tape of the process.
The wheel was held at an angle in a device so that the technician had unobstructed access to the bearing well in the center of the hub. A heating element was removed from the bearing well and at the same time the technician removed a lid from an adjacent styrofoam cooler (two twelve packs and Ice size). The cooler was filled with perhaps 50 completed bearing stacks each tensioned, greased and on its own assembly axel. The container was lined with dry ice and one could see the vapor as the lid was removed. The technician took out one set, oriented the axel and simply pushed it along with the chilled bearing stack into the bearing well in the hub - by hand - till it bottomed6 seconds? The final process removed the assembly axel and put a bearing cap with seal and shim in place with the five screws. That was it.
At the factory, on the assembly line for wheels - the bearing assembly went as follows. I witnessed this on an English language tape of the process.
The wheel was held at an angle in a device so that the technician had unobstructed access to the bearing well in the center of the hub. A heating element was removed from the bearing well and at the same time the technician removed a lid from an adjacent styrofoam cooler (two twelve packs and Ice size). The cooler was filled with perhaps 50 completed bearing stacks each tensioned, greased and on its own assembly axel. The container was lined with dry ice and one could see the vapor as the lid was removed. The technician took out one set, oriented the axel and simply pushed it along with the chilled bearing stack into the bearing well in the hub - by hand - till it bottomed6 seconds? The final process removed the assembly axel and put a bearing cap with seal and shim in place with the five screws. That was it.
30064
Mike V. #30064
Damn, you make it sound so easy. Heat is the key - I know that now. I'm told +210??. Next time I'll take the bare wheel to the local pizza kitchen.
You are correct, I'm told by the gurus the bearing stack should slide right in...with adequate heat. Have plenty of tanks on hand and be prepared to move the flame slowly for at least 10 to 20 minutes on both sides simultaneously.
That's great information to know you experienced the factory installation first hand. Thanks!
You are correct, I'm told by the gurus the bearing stack should slide right in...with adequate heat. Have plenty of tanks on hand and be prepared to move the flame slowly for at least 10 to 20 minutes on both sides simultaneously.
That's great information to know you experienced the factory installation first hand. Thanks!
I found the numbers for the frictional moment...
The frictional moment of the wheel bearings is 15 – 30 Newton centimeters (Ncm) or 2.655 inch pounds (pound force inches) measured with torque wrench that is equipped with a follow-up needle. The axle nut torque for determining the original bearing pre-load is 32.5 – 34.7 foot pounds. That is also the torque recommended for the front and rear axel nuts in situ. I set the bearings up dry and check the pre-load with an inch pound wrench and also by feel using my thumbs to move the center tube. Use a surface plate and garnet paper to take the "wedding ring" shim down a bit if you need to and they are available in several sizes if you dont have the .05 shims. When I’m happy with the pre-load I then pack and assemble the bearing stack and put the assembly in the freezer until the wheel is ready. This follows what I saw in the tape and what I was taught.
There were several different procedures put forward here none of which match the original factory installation exactly. My take on the assembly is that the time to heat the hub is the determining factor. I put the bearing stack in the freezer for an hour or so prior to installing. When the center of the wheel hub gets to a point where you can watch spit bubble when you wipe a little on the installation side of the casting the axle and bearing stack will slide right in literally with a soft plunk. I use an 850 w heat gun. Before that I used two propane torches one held on either side moving constantly. Quick way to set yourself on fire...heat gun better.
The frictional moment of the wheel bearings is 15 – 30 Newton centimeters (Ncm) or 2.655 inch pounds (pound force inches) measured with torque wrench that is equipped with a follow-up needle. The axle nut torque for determining the original bearing pre-load is 32.5 – 34.7 foot pounds. That is also the torque recommended for the front and rear axel nuts in situ. I set the bearings up dry and check the pre-load with an inch pound wrench and also by feel using my thumbs to move the center tube. Use a surface plate and garnet paper to take the "wedding ring" shim down a bit if you need to and they are available in several sizes if you dont have the .05 shims. When I’m happy with the pre-load I then pack and assemble the bearing stack and put the assembly in the freezer until the wheel is ready. This follows what I saw in the tape and what I was taught.
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30064
Mike V. #30064
Sorry I've been away with the completion of the rear snowflake bearing project, I had to travel to Bakersfield for some family health matters while the project here in San Diego had to wait.
The bearings are installed (dry) in the rear hub and I have been doing a lot of experimentation with pre-load and spacer tool fitment. First of all, I wasn't comfortable with the spacer tool I received; the ends were not cut perpendicular and the inside diameter was much greater than the axle diameter of 17mm which didn't allow the spacer to center itself. And with the ends cut unequal the spacer was applying unequal pressure during torque on the inside bearing race and in my opinion giving me incorrect feedback during the pre-load procedure. Some may consider this anal but it was my opinion for such an important application towards safety and function...I wanted to be sure and be thorough for accuracy...needed or not. The amount of education I received in return was valuable. And made a significant difference in the pre-load determination.
I had the spacer tool ends turned at my machinist friend shop and he also fitted some simple pvc interior inserts so that the spacer tool now slid accuartely on the axle and it's outer faces applied well distributed pressure to the inside race of the bearing cage. Here's some photos of the final product...
The bearings are installed (dry) in the rear hub and I have been doing a lot of experimentation with pre-load and spacer tool fitment. First of all, I wasn't comfortable with the spacer tool I received; the ends were not cut perpendicular and the inside diameter was much greater than the axle diameter of 17mm which didn't allow the spacer to center itself. And with the ends cut unequal the spacer was applying unequal pressure during torque on the inside bearing race and in my opinion giving me incorrect feedback during the pre-load procedure. Some may consider this anal but it was my opinion for such an important application towards safety and function...I wanted to be sure and be thorough for accuracy...needed or not. The amount of education I received in return was valuable. And made a significant difference in the pre-load determination.
I had the spacer tool ends turned at my machinist friend shop and he also fitted some simple pvc interior inserts so that the spacer tool now slid accuartely on the axle and it's outer faces applied well distributed pressure to the inside race of the bearing cage. Here's some photos of the final product...
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30064
Mike V. #30064
At this point I was able to determine pre-load very consistently and accurately. At 30 & 35 Ft-lbs I found a very smooth axle rotation with no axial lash by grabbing the outside ends of the axle and wiggling back and forth. Very pleased with the results, like glass with no slop.
The final test will be the "wiggle test" when the wheel is actually installed in the bike.
The final test will be the "wiggle test" when the wheel is actually installed in the bike.
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30064
Mike V. #30064
After I determined pre-load it was time to pack bearings. The syringe trick for the right side bearing works very well and to be honest, may be the way I pack and service bearings in the future instead of the old-school glob-in-palm. This picture shows the grease that was forced out of the cage after tension to the bearing stack after greasing the bearing with syringe.
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30064
Mike V. #30064
And the left side bearing retainer cap with new seal. As mentioned earlier there's two different thoughts on the top-hat position. I believe either one is fine and will work, I chose the brim to be inside.
Notice the obvious wear-grooves of the 3-wiper grease seal on the top-hat. I should (and will) replace this top-hat spacer.
Notice the obvious wear-grooves of the 3-wiper grease seal on the top-hat. I should (and will) replace this top-hat spacer.
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30064
Mike V. #30064
That's it for the rear guys. Now can someone help me figure out these weird 1978 snowflake fronts? No 4-pin collar on this wheel. Do I pry the seals out? Any help on the bearing stack removal is appreciated. I sure hope all of this is helpful to someone.
Here's the right side (front).
Here's the right side (front).
