[DeTomaso] Wheel bearing issues
Dick Koch
arkoch at earthlink.net
Wed Oct 3 21:49:39 EDT 2007
Fred, I have no reason to doubt your statement that the amount of work
and time it takes to properly set the bearings on a Corvette is an
arduous process.
In my original post, the side item I mentioned was relating the merits
of the techniques Timken discussed in their reference material. I
wasn't speaking specifically about the Pantera but in general on how
Timken recommended tapered roller bearings be installed.
As far as my Pantera, for the front wheel bearings I use the simplistic
and inexact method most mechanics I have seen use - tighten the bearing
until the wheel is hard to turn and back off half a turn or until it
rotates freely. There is no end play in this simplistic and inexact
method to set the bearing.
I checked the front wheel bearings this past winter when I had the car
down and found them in great shape. This isn't a great testimonial
since I only had 8,000 miles on the car since I rebuilt the front and
rear suspension. Since it is easy to inspect and service the front
bearings, I don't go through any exacting process to insure the bearings
are installed perfectly.
It is a different story for the rear axle assembly. Given the
difficulty and time consuming task of inspecting and servicing the
tapered roller bearings in my modified rear axle assembly, I went to
great lengths to insure that I used the method that insured the most
durable and lasting installation. Following Timken's advice, I used
their measured preloaded technique of applying 0.001 to 0.003 of an inch
preload.
By the way, in the design I used for the tapered roller bearing
conversion, a press is not required to install the bearings.
With the new rear axle design, I do an external check on the rear axle
assemblies each month. I check for wobble and noise, inspect the
inboard seal for leakage as well as any indication that the outboard
seal is leaking. So far so good.
Well enough of that. I'm sure this thread is now becoming as boring to
folks as many of the others on this forum tend to be after a subject is
beat to death.
By the way, what projects are you working on now? It would be
interesting to see some more pictures of and dialog on some of your
latest creations.
Dick Koch - Atlanta
F&D Terry wrote:
> Your post was easily understood. I think the procedure for setting
> proper end play on Corvette axles is about as involved as doing preload
> on a Pantera. Both require a press, dial indicator and a handful of
> shims, or in the case of a spacing sleeve a lathe sure helps in trimming
> the sleeve to a proper length. Having done both, they each require about
> the same time and care to insure a proper outcome.
>
> Fred T.
>
> Dick Koch wrote:
>
>
>> Fred, what a garble de goop message. Sorry about that.
>>
>> It should have read as follows:
>>
>> Fred, you are right when you talk about acceptable. Both preload and
>> end play techniques work.
>>
>> Timken told me it is a matter of skill and mostly the time available
>> that should guide folks in determining which technique to use.
>>
>> In my prior discussions with the Timken techs when I was designing my
>> axle conversion, they said they don't push the preload technique for
>> general use for the reason I gave. The end play technique provides
>> "acceptable " results. The preload technique is preferred but not for
>> general use.
>>
>> Dick Koch - Atlanta
>>
>> Dick Koch wrote:
>>
>>
>>
>>> F&D Terry wrote:
>>>
>>>
>>>
>>>> Dick,
>>>>
>>>> There seems to be two acceptable schools of thought concerning
>>>> preload. The Corvette shop manuals for '63 forward specify a .001" to
>>>> .007" free play to be within acceptable limits for the taper bearing
>>>> rear uprights.
>>>>
>>>>
>>>> >From a '63 shop manual, "The tapered roller spindle bearings should
>>>>
>>>>> have
>>>>>
>>>>>
>>>>>
>>>> end play of .001"-.007". Check end play and, when necessary, adjust
>>>> as follows." I have owned many of these cars and have never had
>>>> problems.
>>>>
>>>> Fred T.
>>>>
>>>> Dick Koch wrote:
>>>>
>>>>
>>>>
>>>>
>>>>> This interesting (to some) topic comes up every now and then. For
>>>>> those with an interest in going through the "whats, hows, and whys"
>>>>> of bearings, visit the Timken automotive tech site at:
>>>>>
>>>>> <http://www.timken.com/products/bearings/techtips.asp>
>>>>>
>>>>> All the issues discussed on this thread (bearings, seals, lubricant,
>>>>> etc.) are covered.
>>>>>
>>>>> For a primer on bearings, Tech Tips "Volume 1" gives a quick
>>>>> overview of bearing topics.
>>>>>
>>>>> For additional information, click on the "here" link at the bottom
>>>>> of the page for additional automotive tech tips.
>>>>>
>>>>> As a side item, it is interesting to note that the technique of
>>>>> "preloading" a tapered roller bearing, as referenced by Timken, is
>>>>> preferable to the "end play" adjustment technique (see "Issue 3,
>>>>> Tech Tips Volume 6).
>>>>> "..... (a) slight preload can be beneficial to the success of long
>>>>> wheel end life. Slight preload can improve bearing, seal and tire
>>>>> life, but only if the entire process is in control. "In control"
>>>>> means that you actually know the bearing setting process will result
>>>>> in a consistent bearing setting range."
>>>>>
>>>>> However, that topic on preloading specifically speaks to the
>>>>> pitfalls of incorrectly preloading a bearing.
>>>>> "The benefits of a light and controlled preload bearing setting are
>>>>> negated if bearing preload force is excessive. Excessive preload can
>>>>> cause high
>>>>> operating temperatures, reduced lubricant life, reduced seal life,
>>>>> and premature bearing damage. Bearing lock-up and/or wheel end
>>>>> separation may occur if the preload force is excessive."
>>>>>
>>>>> Since it takes a skilled tech, spending the time necessary to set a
>>>>> correct preload, Timken recommends in the automotive tech section to
>>>>> use the "end play" bearing adjustment procedure used by the majority
>>>>> of mechanics. As per Timken, "This method requires the least skill
>>>>> and has proven to be the overall best technique for general field
>>>>> installation and maintenance."
>>>>>
>>>>> Dick Koch - Atlanta
>>>>>
>>>>> MikeLDrew at aol.com wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> In a message dated 10/2/07 20 42 44, pantera at pobox.com writes:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> What seems to have gone wrong with mikes car is a lack of lube. I
>>>>>>> dont see
>>>>>>> ANY!
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> Yeah, me neither. Trust me, it was there at one point, not too
>>>>>> long ago. What you couldn't see in the close-up photos was that
>>>>>> there was grease residue all over the surface of the hub. The
>>>>>> grease seemed to transform to oil as the heat built up, and then
>>>>>> all leaked out, apparently?
>>>>>>
>>>>>> I got both spindles off today (passenger side seems fine), and will
>>>>>> shortly dismantle them both. I aim to see if the passenger side
>>>>>> is adequately lubricated or not.
>>>>>>
>>>>>> Lessons have been learned, no doubt!
>>>>>>
>>>>>> Mike
>>>>>>
>>>>>>
>>>>>> **************************************
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