Home » Public Forums » GMCnet » Matched bearing set question (how are they "matched")
| Matched bearing set question [message #87512] |
Sun, 06 June 2010 10:57  |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Ken H posted this comment on the current bearing question:
"IMHO, you've been very lucky that those bearings have not failed; they were
very ineptly installed according to all I've read, heard, and experienced
over the past 12 years. To have mixed the components of different bearing
sets in that manner is unconscionable.
No doubt in my mind whatsoever that I'd install new Timken A23 sets, making
sure the spacers were engraved "0.0095". Any other choice is, IMHO, "penny
wise and pound foolish"."
I have always thought that bearings came in sets, and the sets were somehow "matched" at the factory when made. However recently I was replacing the wheel bearings on my Utility Trailer and when I went to get them at NAPA, they asked if I wanted both the cones and the cups. I replied I wanted a full matched set and they looked up the numbers and came out with cones in one box and cups in another. No "set" anymore. Mix and match.
Is this common now? What, if anything, is done to make a "matched set" that we used to get? Has manufacturing changed so the it is not necessary to "match" any more? Or am I just seeing the general lack of quality in many parts where inexpensive beats precision? Anyone know?
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Matched bearing set question [message #87551 is a reply to message #87515] |
Sun, 06 June 2010 16:32  |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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| Quote: |
...I'd install new Timken A23 sets, making sure the spacers were engraved "0.0095". Any other choice is, IMHO, "penny wise and pound foolish".".....
....I was replacing the wheel bearings on my Utility Trailer .... came out with cones in one box and cups in another.
Timken still makes the set.....ask for it by name Timken Bearing Set 23.I perfer to order it from one of our GMC suppliers.
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Looks like we are talking 'apples & oranges'. Some are referring to front wheel bearings on a GMC. Others are referring to wheel bearings on a utility trailer.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: [GMCnet] Matched bearing set question [message #87560 is a reply to message #87557] |
Sun, 06 June 2010 18:44 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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| Harry wrote on Sun, 06 June 2010 19:27 |
I had a noisy axle bearing on my '94 Caprice wagon. I thought I could buy a new bearing. No such luck. The bearing does not have an inner race. The ball bearings run right on the axle. When the case hardening wears out, you buy a new axle and bearing.
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Sir: you can get an axle saver bearing assembly. It moves the bearings to a new surface. The seal is made in the assembly.
Auto Zone #TRP1559TV $29.99
C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] Matched bearing set question [message #87563 is a reply to message #87551] |
Sun, 06 June 2010 18:55 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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You're right, John, but it's more like Oranges and Tangerines.
In case anyone doesn't already understand:
The common tapered roller bearings (Oranges) used in the front hubs of most
older vehicles, in the rear hubs of the GMC, on trailer axle hubs, and many
other applications are made up of inner and outer bearing sets, each of
which includes and inner and outer race. Those bearing sets are mounted so
that tightening the hub retaining nut "squeezes" the tapered bearings toward
each other, thereby setting the clearance for each roller bearing set.
Typically, the procedure for installing and adjusting such bearings is to
tighten them to a moderate torque value while turning the hub. That
ensures that the bearings are properly seated, eliminating excess grease
between the rollers and the races. The nut is then backed off and
re-tightened finger tight, just to re-seat the clearance to near zero.
Finally, the castellated nut is backed off just enough to allow a cotter
pin to be inserted to lock the nut. That procedure, or the recommended
equivalent, is intended to establish a slight amount of axial clearance.
That is, the hub will move in and out a certain distance. In fact, some
adjustment procedures require the use of a dial indicator to measure that
movement.
The GMC's front wheel bearings are tapered roller bearings very similar to
the Oranges discussed above, but they're enough difference to qualify as
Tangerines instead: The GMC bearings CANNOT be adjusted by turning the hub
nut. I don't know how much "play" can be tolerated in a front wheel drive
vehicle's wheel bearings, but it must be very little, because GMC chose to
keep it very tight -- on the order of only 0.0095" (0.10" is not uncommon,
or is at least tolerable, for some Oranges).
In order to ensure correct adjustment of the bearings, GMC chose to
establish the clearance by placing a spacer between the outer races and to
clamp those races tightly together (140 to 280 ft-lb on the spindle nut!).
No more finger tight & back off a little -- now it's got to be JUST RIGHT.
For a long time, it was considered appropriate to clamp the bearing set into
a vice and measure the bearing clearance with a feeler gauge before
installing it into the hub and knuckle assembly. But that procedure did not
adequately allow for the possible build up of manufacturing tolerances in
the machining of the bearings, hub, and knuckle; it was still possible for
the bearings to wind up too loose or too tight. So GMC and Timken resorted
to tailoring each spacer to precisely establish the 0.0095" clearance which
is not the standard.
So, while the GMC's front wheel bearings are tapered rollers, they're as
different from common tapered rollers as tangerines are from oranges.
I don't know how widely distributed, and understood, the specifications are
for the A-23 bearing set, but I'm not going to waste my time, money, and
safety empirically determining whether Bower, SKF, Ding Bao Pong, nor anyone
else can make them better or cheaper than TImken. I'm sticking with the
Timken A-23 set.
HTH,
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
On Sun, Jun 6, 2010 at 5:32 PM, John Sharpe <johnasharpe@earthlink.net>wrote:
>
>
> Quote:
> > ...I'd install new Timken A23 sets, making sure the spacers were engraved
> "0.0095". Any other choice is, IMHO, "penny wise and pound foolish".".....
> >
> > ....I was replacing the wheel bearings on my Utility Trailer .... came
> out with cones in one box and cups in another.
> >
> > Timken still makes the set.....ask for it by name Timken Bearing Set 23.I
> perfer to order it from one of our GMC suppliers.
>
>
> Looks like we are talking 'apples & oranges'. Some are referring to front
> wheel bearings on a GMC. Others are referring to wheel bearings on a utility
> trailer.
> --
> John Sharpe
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Matched bearing set question [message #87565 is a reply to message #87551] |
Sun, 06 June 2010 19:00 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| John Sharpe wrote on Sun, 06 June 2010 14:32 |
Looks like we are talking 'apples & oranges'. Some are referring to front wheel bearings on a GMC. Others are referring to wheel bearings on a utility trailer.
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Yes, mine was a general question about the availability and need for "matched sets" in bearings these days. I was wondering if the quality and technology of bearings has changed so you can "mix and match" cones and cups. If I still had my GMC I would certainly look for timken bearing sets from people like the Jim's but what about the general situation? As I said, when I wanted a set of bearings for my utility trailer, they were two part numbers, one for the cones, one for the cups and came in different boxes. Is this the way things are going now?
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Matched bearing set question [message #87570 is a reply to message #87565] |
Sun, 06 June 2010 19:44 |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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Senior Member |
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Rob, I don't see a problem with purchasing bearings and cones for utility trailers and similar applications separately. As Ken noted you will be setting the clearance when you install them. Unlike installing the bearings in the front axle of a GMC.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: [GMCnet] Matched bearing set question [message #87574 is a reply to message #87565] |
Sun, 06 June 2010 19:51 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| idrob wrote on Sun, 06 June 2010 19:00 |
As I said, when I wanted a set of bearings for my utility trailer, they were two part numbers, one for the cones, one for the cups and came in different boxes. Is this the way things are going now?
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As long as I have been playing with cars all the tapered roller bearings I ran into, mostly front wheel bearings, came as separate items. It may not be a degrade in parts but the bearing QC may be so high as to make this possible. Ball bearings would come, assembled, with the inner and outer races. The GMC MH front bearings is the first instance I have seen (realize this is not an extensive experience) of a matched bearing set. This is part of the reason I started the other thread.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Matched bearing set question [message #87593 is a reply to message #87570] |
Sun, 06 June 2010 23:13 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Senior Member |
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| John Sharpe wrote on Sun, 06 June 2010 17:44 |
Rob, I don't see a problem with purchasing bearings and cones for utility trailers and similar applications separately. As Ken noted you will be setting the clearance when you install them. Unlike installing the bearings in the front axle of a GMC.
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Thank you all for helping me understand the difference between the GMC set and other kinds of bearings. As usual,the combined knowledge of this group is fantastic. I sure appreciate it.
Rob Allen
former owner of '76 x-PB
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