Bearing failues and loose dive axle nuts

P

patrick flowers

New member
Sep 19, 1997
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>
> Can anyone shed some light on why a drive axle nut would loosen?
> (Patrick, didn't you once mention your coach had a loose nut when you
> checked it?) Sleep's going to hard to find until I hear some response
> to this puzzle.

Phil,

Yes I did find this(along with other nightmarish surprises) when I
rebuilt my front end. The only plausible explanation(other than
incompetence) I've come up with is the possibility that some trash was
allowed behind the axle and after the coach was run a few miles, this
was ground up and allowed the play. This is a documented problem with
ball joints. In my case though, it wouldn't surprise me that the
bearings were improperly installed(some room left between the bearings
and then they pulled together under load).

One thing I plan to do after driving the coach a couple hundred miles is
retorque the axle nuts to be sure.

Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Lanier, wow! what a tale of woe! I'm going to have a hard time sleeping
now worrying about my GMC's front wheels flying off without warning.

I once found that big nut with the cotter key on the wheel end of one of
the drive axles only finger tight. I tighten it to the shop manual
specs but have never figured out why it was loose it the first place.
It has not come loose again but I'm still leary of it.

I'm wondering, Lanier, if a loose drive axle nut could have caused the
wheels coming off your coach. When you finally came to a stop and found
the wheel, was the axle still attached?

Can anyone shed some light on why a drive axle nut would loosen?
(Patrick, didn't you once mention your coach had a loose nut when you
checked it?) Sleep's going to hard to find until I hear some response
to this puzzle.

Sleepless in Signal Mt.
Phil Stewart
'76 Transmode
 
Phil not to worry about your drive axel nut. If it is secured with a cotter
pin there is no way for it to work loose. Someone left the nut in that
condition.

Phil if you install the correct bearings you can stop worrying about this
problem.

>Lanier, wow! what a tale of woe! I'm going to have a hard time sleeping
>now worrying about my GMC's front wheels flying off without warning.
>
>I once found that big nut with the cotter key on the wheel end of one of
>the drive axles only finger tight. I tighten it to the shop manual
>specs but have never figured out why it was loose it the first place.
>It has not come loose again but I'm still leary of it.
>
>I'm wondering, Lanier, if a loose drive axle nut could have caused the
>wheels coming off your coach. When you finally came to a stop and found
>the wheel, was the axle still attached?
>
>Can anyone shed some light on why a drive axle nut would loosen?
>(Patrick, didn't you once mention your coach had a loose nut when you
>checked it?) Sleep's going to hard to find until I hear some response
>to this puzzle.
>
>Sleepless in Signal Mt.
>Phil Stewart
>'76 Transmode
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
>
> Phil not to worry about your drive axel nut. If it is secured with a
> cotter pin there is no way for it to work loose. Someone left the
> nut in that condition.

Well, the cotter pin prevents the nut from turning, but it doesn't
maintain torque. If the bearings are properly installed, the 140lbft
plus of torque should hold everything nicely. The axle nut basically
"pinches" the bearing inner races between the shoulder on the hub and
the shoulder on the stub axle. I can see where, if someone hammered the
bearings on or used a press, they could leave some play between the
races, mistakenly thinking either that everything is pulled up tight or
that torquing the stub axle will tighted it up. After using the Thoma
tools, I think using an impact wrench to pull everything together is a
great idea. It nearly eliminates the possibility of leaving any play
between the bearing races. However, I still think the cost of a 25 cent
cotter pin is cheap insurance to check the torque on that nut
occasionally.

My $.02,
Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Patrick what do you mean by the statement " I think using an impact wrench
to pull everything together is a
>great idea" How do you do it?

>>
>> Phil not to worry about your drive axel nut. If it is secured with a
>> cotter pin there is no way for it to work loose. Someone left the
>> nut in that condition.
>
>Well, the cotter pin prevents the nut from turning, but it doesn't
>maintain torque. If the bearings are properly installed, the 140lbft
>plus of torque should hold everything nicely. The axle nut basically
>"pinches" the bearing inner races between the shoulder on the hub and
>the shoulder on the stub axle. I can see where, if someone hammered the
>bearings on or used a press, they could leave some play between the
>races, mistakenly thinking either that everything is pulled up tight or
>that torquing the stub axle will tighted it up. After using the Thoma
>tools, I think using an impact wrench to pull everything together is a
>great idea. It nearly eliminates the possibility of leaving any play
>between the bearing races. However, I still think the cost of a 25 cent
>cotter pin is cheap insurance to check the torque on that nut
>occasionally.
>
>My $.02,
>Patrick
>--
>Patrick Flowers
>Mailto:patri63
>
>The GMC Motorhome Page
>http://www.gmcmotorhome.com
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
>
> Patrick what do you mean by the statement " I think using an impact
> wrench to pull everything together is a >great idea" How do you do
> it?

Tom, check out the "Tech" page on my web site. Ken's tools are designed
to use an impact wrench to provide the motivation for disassembly and
assembly. It looks kind of scary in the video, but it works great.
I've got a cheap Craftsman compressor that shuts off at 120psi and a
worn out B&D 1/2 in. impact wrench(I like it cause it's hard to break
anything with it) and it worked just fine.

Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
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