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Re: [GMCnet] rear axle - bearing clearance [message #260372] Thu, 28 August 2014 16:55 Go to next message
Tom Whitton   United States
Messages: 235
Registered: February 2004
Location: Paducah, KY
Karma: 0
Senior Member
The left rear rear drum would not go for me so I called my friend Bob Stone, who is certainly a better mechanic than me. He came to my garage and had the same problem. We found the problem to be the bearing and axle clearance or lack thereof. The bearing ID using calipers is 1.614. The axle OD measures 1.628. According to this measurement, the axle is .014 larger than the bearing ID. I don't own micrometers but plan to borrow some to get accurate measurements. Regardless of accuracy, the axle is obviously too large for the bearing. Don't ask me how mechanics that I have hired to work on the brakes got the hub installed. I would say with great difficulty. It was a total bi--- to remove the hub!

Can anyone tell me what an acceptable tolerance axle-bearing should be? From what I found searching the internet, the axle should not be more than .002 smaller than the bearing ID. My axle is larger than the bearing. I don't know if .002 is a universal tolerance or if the tolerance should be different with a GMC motorhome. When I learn what the axle size should be I can remove the axle and take it to a machine shop to be accurately turned to the correct size. If anyone has better ideas, I will appreciate hearing them.

One last thing, I tried to put the left center hub on the rear rear and it would not go on either. It looks to me like the axle on my coach is very definitely oversize. Why I can not answer.

Looking forward to your answers,

Tom Whitton
Paducah, KY
26 foot updated GMC
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Re: [GMCnet] rear axle - bearing clearance [message #260375 is a reply to message #260372] Thu, 28 August 2014 18:11 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Tom,

I just went out and measured my used spare spindle and 2 spare bearings.
By my cheap digital calipers, they're all right at 1.621"+-0.00005

Our calipers could easily differ by that 0.007.

Who made the bearings? If not Timken, I'd find some.

​HTH,​

Ken H.

On Thu, Aug 28, 2014 at 5:55 PM, Tom Whitton
wrote:

> The left rear rear drum would not go for me so I called my friend Bob
> Stone, who is certainly a better mechanic than me. He came to my garage
> and had the same problem. We found the problem to be the bearing and axle
> clearance or lack thereof. The bearing ID using calipers is 1.614. The
> axle OD measures 1.628. According to this measurement, the axle is .014
> larger than the bearing ID. I don't own micrometers but plan to borrow
> some to get accurate measurements. Regardless of accuracy, the axle is
> obviously too large for the bearing. Don't ask me how mechanics that I
> have hired to work on the brakes got the hub installed. I would say with
> great difficulty. It was a total bi--- to remove the hub!
>
> Can anyone tell me what an acceptable tolerance axle-bearing should be?
> From what I found searching the internet, the axle should not be more than
> .002 smaller than the bearing ID. My axle is larger than the bearing. I
> don't know if .002 is a universal tolerance or if the tolerance should be
> different with a GMC motorhome. When I learn what the axle size should
> be I can remove the axle and take it to a machine shop to be accurately
> turned to the correct size. If anyone has better ideas, I will
> appreciate hearing them.
>
> One last thing, I tried to put the left center hub on the rear rear and
> it would not go on either. It looks to me like the axle on my coach is
> very definitely oversize. Why I can not answer.
>
> Looking forward to your answers,
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] rear axle - bearing clearance [message #260388 is a reply to message #260375] Thu, 28 August 2014 19:39 Go to previous messageGo to next message
Harry is currently offline  Harry   Canada
Messages: 1888
Registered: October 2007
Location: Victoria, BC CANADA
Karma: 3
Senior Member
I have heated bearings with a quartz floodlight to gain a thou or two.
If you do, make sure it's on all the way before it cools.
Re: [GMCnet] rear axle - bearing clearance [message #260390 is a reply to message #260372] Thu, 28 August 2014 19:54 Go to previous messageGo to next message
Tom Whitton   United States
Messages: 235
Registered: February 2004
Location: Paducah, KY
Karma: 0
Senior Member
Ken,

Thanks for the measurement. I'll put the information to good use tomorrow and will report what I find when I have something. I'm borrowing micrometers as a first step. My bearings are Bower but the hub on the same side would not go over the axle either. That adds to the mystery. I'm also going to go to the bearing store to measure new bearings.

Tom


Re: [GMCnet] rear axle - bearing clearance
To: gmclist
Message-ID:

Content-Type: text/plain; charset=UTF-8

Tom,

I just went out and measured my used spare spindle and 2 spare bearings.
By my cheap digital calipers, they're all right at 1.621"+-0.00005

Our calipers could easily differ by that 0.007.

Who made the bearings? If not Timken, I'd find some.

?HTH,?

Ken H.

On Thu, Aug 28, 2014 at 5:55 PM, Tom Whitton
wrote:

> The left rear rear drum would not go for me so I called my friend Bob
> Stone, who is certainly a better mechanic than me. He came to my garage
> and had the same problem. We found the problem to be the bearing and axle
> clearance or lack thereof. The bearing ID using calipers is 1.614. The
> axle OD measures 1.628. According to this measurement, the axle is .014
> larger than the bearing ID. I don't own micrometers but plan to borrow
> some to get accurate measurements. Regardless of accuracy, the axle is
> obviously too large for the bearing. Don't ask me how mechanics that I
> have hired to work on the brakes got the hub installed. I would say with
> great difficulty. It was a total bi--- to remove the hub!
>
> Can anyone tell me what an acceptable tolerance axle-bearing should be?
> From what I found searching the internet, the axle should not be more than
> .002 smaller than the bearing ID. My axle is larger than the bearing. I
> don't know if .002 is a universal tolerance or if the tolerance should be
> different with a GMC motorhome. When I learn what the axle size should
> be I can remove the axle and take it to a machine shop to be accurately
> turned to the correct size. If anyone has better ideas, I will
> appreciate hearing them.
>
> One last thing, I tried to put the left center hub on the rear rear and
> it would not go on either. It looks to me like the axle on my coach is
> very definitely oversize. Why I can not answer.
>
> Looking forward to your answers,
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Re: [GMCnet] rear axle - bearing clearance [message #260414 is a reply to message #260372] Fri, 29 August 2014 01:50 Go to previous message
Adrien G. is currently offline  Adrien G.   United States
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
Senior Member
Tom,

Has the spindle been replaced? With that much interference there is no way to ever get the hub on. The bearing would have to be red hot to expand enough to slide on, rendering the bearing useless.

My spindle at the inner bearing are 1.6238 to 1.6245 OD. The bearing ID 1.625 +.0002 -.0000.

Clearence of .002 inch between spindle and bearing is a sloppy fit, could allow the bearing to skate on the spindle. As the bearing heats up the pindle expands and (with the correct clearence) some or all of the cleareences are taken up, tightning up the bearing to the spindle.

If the spindle has to be resized, the shoulder radius must be blended in and polished. To eliminate stress breaks.





Tom Whitton wrote on Thu, 28 August 2014 16:55
The left rear rear drum would not go for me so I called my friend Bob Stone, who is certainly a better mechanic than me. He came to my garage and had the same problem. We found the problem to be the bearing and axle clearance or lack thereof. The bearing ID using calipers is 1.614. The axle OD measures 1.628. According to this measurement, the axle is .014 larger than the bearing ID. I don't own micrometers but plan to borrow some to get accurate measurements. Regardless of accuracy, the axle is obviously too large for the bearing. Don't ask me how mechanics that I have hired to work on the brakes got the hub installed. I would say with great difficulty. It was a total bi--- to remove the hub!

Can anyone tell me what an acceptable tolerance axle-bearing should be? From what I found searching the internet, the axle should not be more than .002 smaller than the bearing ID. My axle is larger than the bearing. I don't know if .002 is a universal tolerance or if the tolerance should be different with a GMC motorhome. When I learn what the axle size should be I can remove the axle and take it to a machine shop to be accurately turned to the correct size. If anyone has better ideas, I will appreciate hearing them.

One last thing, I tried to put the left center hub on the rear rear and it would not go on either. It looks to me like the axle on my coach is very definitely oversize. Why I can not answer.

Looking forward to your answers,

Tom Whitton
Paducah, KY
26 foot updated GMC
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