Wheel bearing adjustment ?

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hambone
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Wheel bearing adjustment ?

Post by hambone » Thu Sep 28, 2006 2:45 pm

Of course ol man Bentley says to use a dial indicator to correctly tighten down the nut and bearing plate, but what do all you recommend for the driveway mechanic? Is the Muir method of "tighten down then loosen 1/2 turn etc." acceptable?

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hambone
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Post by hambone » Sat Sep 30, 2006 3:55 pm

Here's what I found doin an internet search (interesting, look who's involved):
OK, I put on new front drums and new inner/outer bearings. Greased the hell out of the bearings and adjusted them. When I adjusted them, I turned the clampnut from loose to until tight, then backed off until I saw the washer move a bit. When I took it out onto the road tonight the front end seemed to vibrate and there was a dull hum from from both wheel ends. Even the left rim felt a bit warm when I got home. Did I adjust these correctly and if not, how do I do it? BTW- its a 70 Westy...
Tristan
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Amskeptic
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Posted: Wed Nov 26, 2003 9:38 pm Post subject:

Your adjustment procedure was within mostly acceptable practice, but for a little greater accuracy, you can torque the clamp nut to 10 ft pounds while rotating the wheel, this helps bed new races if you have installed them, and preloads the roller bearings, then, after you have backed-off the nut until the washer moves a bit, you clamp the nut and then make sure you can move the washer easily with a flat bladed screwdriver. I have had instances where the washer backed nicely with the clamp nut because it was *stuck* to the clamp nut with a grease glue effect, then the washer would not move worth a damn with the screwdriver test. The screwdriver "move the washer easily" test ensures about .0015-.002" tolerance. You can feel .003" by rocking the wheel.
Colin

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ratwell
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Posted: Thu Nov 27, 2003 12:06 pm Post subject:

This photo from the VW workshop manual depicts what Colin is trying to explain.

I've lost the link I had to the SKF site wrt bearing life. It basically said that bearing life is maximized when it is set from -0.001" to 0.001". Of course if the application specifies endplay rather than preload as is the case here then 0.001" is your goal.

According to SKF, when bearing endplay was greater than 0.001" and less than 0.005" as Bentley states, bearing life was quickly reduced to half on a graph with a decreasing slope. You can imagine how the tapered roller bearing can wear when improperly adjusted but you aren't going to see the wear patterns from such a short drive. After enough miles you'll see wear on the large end of the roller when it's too tight and on the small end when it's too loose. The race in the cup will blue from heat, or gall and the list goes on.
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splitty
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Posted: Thu Nov 27, 2003 1:05 pm Post subject:

Thanks to the both of you...one thing I noticed on the drivers side was that when I put the new grease seal in it wasn't quite flush...so the inner bearing wasn't able to go all the way back. As for the adjustment I had them way too loose....this time after I tightened the clamp nut I kept trying to pry the washer (as shown in the link pic- thanks Ratwell) until it moved just a hair, but not much at all. I took it out a bit later and it rides great, no hum and now I can go eat. Thanks again guys and Good Holiday To You!
Tristan
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1969 Crew Cab- almost done
1970 Westfalia- daily driver

vdubyah73
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Post by vdubyah73 » Sun Oct 01, 2006 7:11 am

I like to adjust with the wheel on and try to wiggle the wheel with hands on top and bottom of the wheel. I like a just perceptable wiggle in the wheel. Rather a little loose than a little tight though. Sucks to smoke a bearing on the side of the road. The outer race will weld itself to the spindle and have to be broken off.

Bill

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hambone
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Post by hambone » Tue Oct 03, 2006 8:06 am

It seemed like a touchy adjustment. The washer was very loose, then just a slight turn made it so it didn't move at all. I turned it just past the "wiggle" spot and everything seems ok. It's hard to tell with new grease becuase it's so sticky.

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hambone
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Post by hambone » Tue Oct 03, 2006 10:10 am

PS I also checked the wheel for exessive heat after a highway run, everything seems normal.

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Amskeptic
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Post by Amskeptic » Tue Oct 03, 2006 4:19 pm

I preload the bearings to slightly tight-ish while *rotating the wheel* then back off until I see the washer just begin to rotate backwards with the adjustment nut. Insert screwdriver between the washer and the hub and try to slide washer sideways by rotating the screwdriver as though you were loosening a screw. Keep in mind that the key in the washer is trapped by the slot in the spindle. If your screwdriver refuses to budge, you need to test for movement again 180* away or try 90* away from your initial test point. A nice slide is not quite easy and certainly not difficult to rotate screwdriver blade.

If you still can rock the wheel at 12 and 6 o'clock, temporarily snug the adjustment nut to maybe 5 ft/lbs while rotating the wheel. If the wheel can still rock at 12/6 o'clock, put your adjustment nut back to the sort-of-easy washer slide position. You need new bearings.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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hambone
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Post by hambone » Wed Oct 04, 2006 8:24 am

Hey, what keeps the grease in at the outer bearing area? Is it just the lock washer?

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Amskeptic
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Post by Amskeptic » Thu Jan 11, 2007 12:42 pm

hambone wrote:Hey, what keeps the grease in at the outer bearing area? Is it just the lock washer?
The outer bearing is fed by grease from the inside of the wheel hub. I do dab a little plug of grease around the lockwasher, but keep the dust cap pretty clean.
Colin

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