Rear bearings, '70 bus.

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ruckman101
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Rear bearings, '70 bus.

Post by ruckman101 » Tue Jul 01, 2014 11:53 pm

So I noticed on our last run on the new engine down to Eugene, Corvallis, Tangent, Willamette valley farmlands, that I had a bearing thrum/hum noise most disconcerting that hasn't diminished since.

My initial response was to inspect the front end. But after tearing down and repacking, nothing really scary there, ancient bearings, a dent in the cage of one outer bearing, but nothing drastic looking. And the noise was still there.

Next suspect, CVs. But then, listening to it riding home from the Lab last Monday, I had an epiphany. Rear wheel bearings, the ones I replaced (no confidence in my abilities) in an effort to address diminishing rear hub tolerances expressed by drums scraping against brake backing plates.

While cleaning and repacking the front wheel bearings, brake shoes looked due. So Sunday I worked the front wheels with new brake shoes and gentle love.

Monday I began the brake job on the rear wheels. Sure enough, the suspect wheel axle nut about spun off by hand after removing the cotter pin. The driver's side wasn't.

Gee, maybe if I just brought the assembly up to torque spec, my bearing thrum/hum noise would be abated. But no, I couldn't let it go and broke it open anyway, without even testing the simple solution. The backing plate would not come off. Finally gave up and got the axle stub and bearings out. Those C-clips are a bear.

Today, reassembled. Eh, I cleaned 'em up and put 'em back in, with new seals. But was willing to reuse the old ones because they came out pretty easy with the seal puller tool. Kinda like the front bearings. Nothing damning. Must have been the loose torque on the wheel/drum. Doh!

Oh, yes, have some photos. Because this tolerance drum scraping brake backing plate issue has been chased and chased. Beyond the stock elements, is an extra "spacer" (big ass flat washer) between the drum and the stock outer spacer. The torque spec tends to compress the spacer components that are of course made of unobtainium now. No replacements available. Haven't got into the other wheel yet. I'd actually forgotten the spacer was there. I even have spanking low mileage drums with splining that's still not being hammered away into slop, and no loss of spec from compression.

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I specced the pads, and they were down 2 mm at the worst from the 8 mm of the new ones. Three years on. But not pretty.

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New brakes good.

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Here's my extra great big washer spacer. It concaved a bit, and yep, compressed, notice the ridge in the center.

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Here's the inner flat surface of the outside spacer that mates with the inner race of the outer bearing assembly. Looked pretty flat, but you can see the lip on the inside in the photo that says, yep, compressed and thinner than it used to be. The beveled edge was against my extra spacer washer, and looked just fine. My extra spacer seemed to mate with the beveled side, so pretty sure this was the face against the inner race of the outer bearing.

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And here's the face of inner race of the outer bearing. The other side rests against the inner spacer and looked better. The damage looks much worse in the photos, but still far from pristine just exactly perfect.

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Here's the outer race of the outer bearing which I left in place and did not remove. Discolored, but no real rut discernible by fingernail. You had to want to feel it, maybe, just barely, sorta.

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And one of the edges of the inner spacer. The other side was just as bad. Stock. I don't recall doing anything three years ago when I put the new bearings in. But notice the hammered in edge with the sharp lip. Thus the issue.

Of course the bearing surfaces of my axle stub were again, less than shiny and new. Here's where the outer bearing rides.

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And the surface where the inner bearing of the axle stub lives.

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So yep, cleaned, re-greased, put it back together. Used new grease seals, had new bearings, but didn't go there. Tomorrow, the axle back on and the brakes on both rear wheels because it's getting hot and the campers need a ride down to the reservoir for their afternoon swim. After today, they're miffed. They wanted it Monday.

I did take the harsh edges off the ridges of the extra spacer and inner spacer with a small file, but didn't flatten them. The brake backing plate did not want to be removed from the bottom dowel. Two days of PB Blaster and repeated efforts from the back with hammer and punch, thought I might be making progress, but it might have only been the deformation dimple in the backing plate the punch seemed to be doing. Didn't really need to take it off anyway. Came off three years ago, though.

Please call me on anything in case my assessment is flirting with disaster and things are direr than I suspect, and thank you for your patience.


neal
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asiab3
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Re: Rear bearings, '70 bus.

Post by asiab3 » Wed Jul 02, 2014 8:15 am

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This is blatant rotation between parts that are supposed to be held together and rotating together. I wish I could tell you why it happened. Possibly due to the lack of torque on the nut, but even then it's supposed to be part of the 100% rotating assembly.

Can you measure the axial dimension with a micrometer? I have a spare set of all 4 early bus spacers that I am willing to part with for what I paid for them if you would like/need them. I'll measure them next weekend. No use though if yours are equal or better, and the problem should be cured before throwing parts at it...

Robbie
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1969 bus, "Buddy."
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Wed Jul 02, 2014 10:10 am

Measuring, Doh! All back together at the moment. The initial bearing replacement was with the thought the bearing races had compressed and were contributing to the scraping. Only did one side, because it had little impact at addressing the issue. So far the additional spacer has been the ticket, but the softer metal compresses rather quickly in comparison, so constantly re-torqueing the axle nut. I would be thrilled with better spacers, but at this point can only speculate on the state of degradation of mine. Should know today after getting the brakes done if I still have a thrum/hum noise, and suspect I'd be interested in spare spacers regardless.

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Re: Rear bearings, '70 bus.

Post by Amskeptic » Wed Jul 02, 2014 10:37 am

ruckman101 wrote:Measuring, Doh! All back together at the moment. The initial bearing replacement was with the thought the bearing races had compressed and were contributing to the scraping. Only did one side, because it had little impact at addressing the issue. So far the additional spacer has been the ticket, but the softer metal compresses rather quickly in comparison, so constantly re-torqueing the axle nut. I would be thrilled with better spacers, but at this point can only speculate on the state of degradation of mine. Should know today after getting the brakes done if I still have a thrum/hum noise, and suspect I'd be interested in spare spacers regardless.

neal
353 ft/lbs on the axle nut then advance ONLY TO THE NEXT cotter hole. There are two holes in the axle shaft. There is no distortion if these directions are followed. But you have distortion. I surmise that the loose axle nut might have inspired you in the past to torque that thing fiercely. I remember that b a washer, some hardware store in Maupin, I believe. We filed to fit.

Amazing how this engineering collapses when we disobey the specifications. Did your not-so-long-ago new bearings slide into the wheel bearing housing easily, or did you have to press them?
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Wed Jul 02, 2014 10:54 am

They did not "slide in easily" then or now. Pressed (?) out and in with a brass drift and gentle taps to coax. I don't think I have ever over-torqued the assembly. And I believe this is a second washer, similarly filed to fit as the first we applied in Maupin lo these many moons ago.

And I do have a returned scraping, but cause not determined. Not even noticed unless the window is down and you're tooling through streets lined with industrial warehouse type structures of concrete that echo it back to you. Otherwise, you don't hear any scraping.


neal
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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Wed Jul 02, 2014 8:29 pm

Well got everything buttoned back up, and took her on a short test drive hitting 50 mph and it seems better. Most likely just a loose axle nut. So it goes. But it still feels like I'm living on borrowed time.


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Re: Rear bearings, '70 bus.

Post by asiab3 » Thu Jul 03, 2014 3:41 pm

ruckman101 wrote:Most likely just a loose axle nut. So it goes. But it still feels like I'm living on borrowed time.


neal.
I don't think my axle nuts were ever torqued enough- I think if you set the bus down to do any initial torquing, you'll never quite line it up right. I think Colin was the one who reminded me to get it as close to final torque as you can before putting any weight on the assembly. I had a low pitched rumble for a week before I pulled the hubcap and found the nut loose, held on only by the cotter pin. The other side had a nut that was plenty tight, but there was still a mm of axial play. New bearings, races, and checking the thickness of the spacers let me cinch the nut down to well over 200 lb/ft before even letting the bus off jack stands. Now both sides are smooth when I get one wheel rotating off the ground in 2nd gear. Also, it's important to get the stub axle seated all the way- if your PO or mechanic seated it by eye instead of by ear then it oculd seat itself on the next turn and end up with play in the shaft. I'm guessing you did it right, but all these things could happen.

Robbie
1969 bus, "Buddy."
100k miles with me.
279k miles on Earth.

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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Thu Jul 03, 2014 8:28 pm

Always have put the bulk of the torque once off the jack stands. Seems tricky to get anything with the wheel off the ground. I certainly put the nut on and tightened before, but will definitely be revisiting after a few miles. No mileage as of yet.


neal
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Re: Rear bearings, '70 bus.

Post by hambone » Fri Jul 04, 2014 5:50 pm

Take a breath, relax, and breathe before you freak yourself out. Ask me how I know.
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Re: Rear bearings, '70 bus.

Post by Amskeptic » Sat Jul 05, 2014 6:48 pm

ruckman101 wrote:They did not "slide in easily" then or now. Pressed (?) out and in with a brass drift and gentle taps to coax.
Chloe was tap tap as the bearings came out and in because the wheel bearing housing had fresh surface outboard of the circlips. But when the bearings got to their home position, they were loose. I used LocTite to help. The reason I mention this, is if the bearings have any lateral movement in the wheel bearing housing, that can lead to chronic deterioration of rear axle nut torque and scraping along industrial alleys.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Mon Jul 07, 2014 10:28 pm

Oi, that didn't help the freak out potential Colin.
I didn't remove the race on the outer, or test it for looseness. The back one went in slowly until it was in the barrel and then slid in easy with taps only to one side. I think side slop is still minimal. We'll be re-checking the torque soon. I seem to have lost my torque wrench purchased expressly for the purpose of applying just exactly perfect specs and did my best to calculate weight in inches from the fulcrum. 200 lbs 21 inches out on the lever, the 21 inch mark between my feet. Problem side needed additional to find a cotter pin hole, side I haven't touched found it's mark right off.

There's nothing like the pressure of a four year old camper hot to hit the lake as it became suddenly summer to motivate you to get the job done.

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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Mon Jul 07, 2014 10:35 pm

Oh, I did take it on a better test drive and the thrum/hum noise is vastly abated. But will be checking the torque sooner rather than later.

neal
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asiab3
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Re: Rear bearings, '70 bus.

Post by asiab3 » Wed Jul 09, 2014 8:47 am

Good to hear. I just ran Colin's wheel bearing procedure on a company golf cart and everyone in the maintnence department thinks I'm a god. You'll feel good when your bus is quieter and torqued properly, I promise. :)
1969 bus, "Buddy."
100k miles with me.
279k miles on Earth.

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Re: Rear bearings, '70 bus.

Post by Amskeptic » Fri Jul 11, 2014 10:27 am

ruckman101 wrote: There's nothing like the pressure of a four year old camper hot to hit the lake as it became suddenly summer to motivate you to get the job done.

neal
Now that thar is a kwinteeshenshal shot of a properly living VW bus family.
=D>
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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ruckman101
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Re: Rear bearings, '70 bus.

Post by ruckman101 » Fri Jul 11, 2014 5:48 pm

Makes it all worthwhile. Second summer for the four-year-old, and he's already madly bus obsessed.


neal
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