🚀 go-pugleaf

In article <2427@sunybcs.UUCP> ugzannin@sunybcs.UUCP (Adrian Zannin) writes:
>
>      1)  Approx. how much would it cost me to have a complete bearing 
>          replacement in the transmission of my 1980 Toyota Corolla SR-5
>          liftback w/5-speed?  I was quoted approx. $300 for the job.  Any
>          suggestions out there?  Is this a little steep?
>
That sounds like a heck of a deal to me.  A few years ago, a friend of mine had
a Datsun 310 that needed a few gears and bearings replaced and the bill was
$600, and that was after we pulled the trani out ourselves!  We called a bunch
of different places, so that seemed to be the going rate.  If the deal is
legit, I'd grab it.
>
>      2)  The bearings in the rear end have started to hum.  How much damage
>          can I expect if I wait a few months to replace them?
> 
If you're luckey, nothing will happen.  If you're really unlucky, the wheels
will lock up, causing lots of damage even if you don't wreck the car.  If
you've got the money, do it, assuming you know what the problem is.


						Mark F. Flynn
						Department of Physics
						Washington University
						St. Louis, MO  63130
						ihnp4!wuphys!mff

------------------------------------------------------------------------------

"There is no dark side of the moon, really.
 Matter of fact, it's all dark."

				P. Floyd

>       1)  Approx. how much would it cost me to have a complete bearing 
>           replacement in the transmission of my 1980 Toyota Corolla SR-5
>           liftback w/5-speed?  I was quoted approx. $300 for the job.  Any
>           suggestions out there?  Is this a little steep?

Looks about right for what amounts to a full rebuild on a manual trans.
The previous comparison to a Datsun 310 really isn't a good one, since
the 310 is a FWD vehicle, if my memory serves me correctly.  Work on FWD
transaxles always seems to cost more.
 
>       2)  The bearings in the rear end have started to hum.  How much damage
>           can I expect if I wait a few months to replace them?

Depends on which bearings are making the noise.  If they're your rear wheel
bearings, probably none.  If the noise is coming from a differential bearing,
(or you're not sure which) you should look into getting it fixed ASAP or
risk replacing the entire unit.  (Replacing the entire unit with one from a
wrecking yard *may* be cheaper anyway - you might want to check into that if
a differential repair is indicated.)

Wheel bearings usually just keep getting noisier until they get so loud
that you have to replace them just to keep your sanity.  I favor milking all 
the mileage out of the original equipment bearings as possible, since they
frequently last longer *after* they start to make noise than the replacements
will after you install them.  Wheel bearings get *real* noisy before they
will freeze up, and the replacement bearings I've gotten have often been of
rather poor quality.

> >       2)  The bearings in the rear end have started to hum.  How much damage
> >           can I expect if I wait a few months to replace them?
> 
...
> Wheel bearings usually just keep getting noisier until they get so loud
> that you have to replace them just to keep your sanity.  I favor milking all 
> the mileage out of the original equipment bearings as possible, since they
> frequently last longer *after* they start to make noise than the replacements
> will after you install them.  Wheel bearings get *real* noisy before they
> will freeze up, and the replacement bearings I've gotten have often been of
> rather poor quality.

One thing to watch out for is *front* bearings.  (I know the original
was about rear bearings, but this is important).  My sister had a small
Ford that had the front bearings go dry (grease 'evaporated').  The
result was a noisy front bearing.  This first manifested itself in Los
Angeles.  As home was north of San Francisco, she decided to just
drive it home before getting the bearing fixed.  After several hours
on the freeway noise was worse and the performance was off.
She stopped at the request of a friendly Highway Patrolman ...  The
wheel then fell off.  A *VERY* overheated bearing had softened the spindle
it rides on enough for it to break.  It was a dull red at the time...

One wonders what would have happened if she had not been pulled over
for a smoking wheel.

Even if you do decide to push the bearings; grease 'em.  Often and well.

-- 

E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

'If you can dream it, you can do it'  Walt Disney

This is the obligatory disclaimer of everything. (Including but
not limited to: typos, spelling, diction, logic, and nuclear war)

In article <2180@amdahl.UUCP> ems@amdahl.UUCP (ems) writes:
>> >       2)  The bearings in the rear end have started to hum.  How much damage
>> >           can I expect if I wait a few months to replace them?
>> 
>
>One thing to watch out for is *front* bearings.  (I know the original
>was about rear bearings, but this is important).  My sister had a small
>Ford that had the front bearings go dry (grease 'evaporated').  The
>result was a noisy front bearing.  This first manifested itself in Los
>Angeles.  As home was north of San Francisco, she decided to just
>drive it home before getting the bearing fixed.  After several hours
>on the freeway noise was worse and the performance was off.
>She stopped at the request of a friendly Highway Patrolman ...  The
>wheel then fell off.  A *VERY* overheated bearing had softened the spindle
>it rides on enough for it to break.  It was a dull red at the time...
>
Another issue with overheated front wheel bearings is that they become
VERY difficult to replace.  The inner bearing race can freze to the spindle
making what should be a rather simple repair into a real monster.
Why risk it, bearings are cheap compared to new spindles.
		Iligitimi non carborundum
			Hank Cohen

> ...
> > Wheel bearings usually just keep getting noisier until they get so loud
> > that you have to replace them just to keep your sanity.  I favor milking all 
> > the mileage out of the original equipment bearings as possible, since they
> > frequently last longer *after* they start to make noise than the replacements
> > will after you install them.  Wheel bearings get *real* noisy before they
> > will freeze up, and the replacement bearings I've gotten have often been of
> > rather poor quality.
> 
> One thing to watch out for is *front* bearings.  (I know the original
> was about rear bearings, but this is important).  My sister had a small
> Ford that had the front bearings go dry (grease 'evaporated').  The
> result was a noisy front bearing.  This first manifested itself in Los
> Angeles.  As home was north of San Francisco, she decided to just
> drive it home before getting the bearing fixed.  After several hours
> on the freeway noise was worse and the performance was off.
> She stopped at the request of a friendly Highway Patrolman ...  The
> wheel then fell off.  A *VERY* overheated bearing had softened the spindle
> it rides on enough for it to break.  It was a dull red at the time...

My mistake.  I should have been more precise in my answer.

My reply was meant to apply to the case of the common, ball-bearing,
permanently-lubricated variety of rear wheel bearing.  This is the type
in question in the case described, I believe.  Roller bearings (the type
usually used on front wheels) will sometimes have a roller break apart
if you wait too long to replace it.  The result of this is that the wheel
will look up, and the bearing may very well weld itself to both the spindle
and the hub.  I have had this happen to me once while driving down the
freeway, and I would personnally rather have a front tire blow out than
have a repeat performance of that!

If you know what bearings are making the noise, and their type, then you
can make a decision about whether or not you should wait to replace them.
If you're in doubt about what is giving the problem, or where it is, it's
better to get it checked into than to get a rather expensive, and possibly
dangerous, surprise.

> Hank Cohen writes:
> In article <2180@amdahl.UUCP> ems@amdahl.UUCP (ems) writes:
> >
> >One thing to watch out for is *front* bearings.  My sister had a small
> >Ford that had the front bearings go dry (grease 'evaporated').  The
> >result was a noisy front bearing.  ... she decided to just
> >drive it home before getting the bearing fixed.  After several hours
> >on the freeway noise was worse and the performance was off.  ... The
> >wheel then fell off.  A *VERY* overheated bearing had softened the spindle
> >it rides on enough for it to break.  It was a dull red at the time...
> >
> Another issue with overheated front wheel bearings is that they become
> VERY difficult to replace. 

OK, what is the difference between a bearing an a CV joint.  My
1981 Dodge Omni, (yup readers, the same one) has "worn front CV
joints".  On one of them (drivers side) the rubber bag that holds
the grease is ripped.  The grease can disappear.  I was quoted at
$270 ($240 labor, $30 parts) to repair this front wheel drive,
traverse engine car.  The mechanic said that it need not be done
soon.  The wheel would eventually fall off but I would get plenty
of warning before that.  I don't plan on keeping the car much
past Sep '86.  (Or maybe even sooner if the VW GTI gets the 16
valve engine in this country earlier than expected) Any
prognosis?

Suspension is also going soft.  Given the above, should I fix it?
What would an approximate cost be?

					"Devil in my car!"
					pZ
-- 
-- Flushed from the bathroom of your heart.

   Paul Czarnecki
   Uniworks, Inc.		decvax!{cca,wanginst!infinet}!emacs!pz
   20 William Street		emacs!pz@cca-unix.ARPA
   Wellesley, MA 02181		(617) 235-2600

> My mistake.  I should have been more precise in my answer.
> 
> My reply was meant to apply to the case of the common, ball-bearing,
> permanently-lubricated variety of rear wheel bearing.  This is the type
> in question in the case described, I believe.  Roller bearings (the type
> usually used on front wheels) will sometimes have a roller break apart
> if you wait too long to replace it.  The result of this is that the wheel
> will look up, and the bearing may very well weld itself to both the spindle
> and the hub.  I have had this happen to me once while driving down the
> freeway, and I would personnally [sic] rather have a front tire blow out than
> have a repeat performance of that!
> 
> If you know what bearings are making the noise, and their type, then you
> can make a decision about whether or not you should wait to replace them.
> If you're in doubt about what is giving the problem, or where it is, it's
> better to get it checked into than to get a rather expensive, and possibly
> dangerous, surprise.
> 
Correct me if I'm wrong, but I believe front bearings are typically taper
bearings, while rear bearings are roller bearings.  Whenever a bearing
starts to make noise, it is subject to catastrophic failure.  I have seen
a rear axle break due to the heat generated by a bad (noisy) rear bearing.

Whenever a bearing starts to make noise, get it fixed.  You are playing
Russian roulette if you don't.

Brian Jones  aka  {ihnp4,}!drutx!qwerty  @  AT&T-IS, Denver
-- 

Brian Jones  aka  {ihnp4,}!drutx!qwerty  @  AT&T-IS, Denver

> Correct me if I'm wrong, but I believe front bearings are typically taper
> bearings, while rear bearings are roller bearings.  Whenever a bearing
> starts to make noise, it is subject to catastrophic failure.  I have seen
> a rear axle break due to the heat generated by a bad (noisy) rear bearing.

:-) Well, you did ask me to correct you if you were wrong! :-)

While I can't swear that it's true in general, and it's certainly *not* true
for most FWD cars, most of the cars that I have dealt with use taper-fit roller
bearings on the front wheels and ball bearings on the rear.  The rear bearings
may be either sealed ('permanently lubricated') or lubricated by differential
lubricant.  The only places I have ever seen a non-tapered roller bearing
are in places like u-joints and steering gears.

My original point was that the ball bearings used in this application are
not very prone to catastrophic failure, while the taper-fit bearings used
on front wheels are much more so.  While there is always a finite chance
of the bearing failing outright, with rear wheel bearings it is usually quite
safe to run them until the noise becomes loud enough to become objectionable.
This may actually require a couple years of normal driving to occur.
Remember, though -- if in doubt, replace!

While I certainly don't want to start an endless stream of people reporting
what kind of bearings a certain car uses in a certain situation, I would
be curious to know if anyone can provide *general* information as to what
bearings are usually used for what purpose (automotive-wise), why they are
used and their failure characteristics.

> OK, what is the difference between a bearing an a CV joint.  My
> 1981 Dodge Omni, (yup readers, the same one) has "worn front CV
> joints".  On one of them (drivers side) the rubber bag that holds
> the grease is ripped.  The grease can disappear.  ...

CV or constant velocity joints serve the same purpose in a front wheel
drive car that U-joints serve on a rear wheel drive car.  That is, they 
allow a flexible connection between the transaxle ( or transmission) and
the drive wheels.  On a fwd car there is a CV joint at each end of each
drive shaft.  One connects to the transaxle and the other to the wheel.
They are called constant velocity joints because they provide for the
linear transfer of angular velocity through the joint.  That is, if a shaft
on one side if the CV joint is run at a constant 3000 RPM a wheel connected
to the other side will run at a constant 3000 RPM regardless of the angle
of the joint.  If you run a constant 3000 RPM into a U-joint you will get an
output that only averages 3000 RPM but actually speeds up and slows down
during a single revolution (play with the U-joints in a socket-wrench set
and you will see what I mean).  This non-linear transfer of rotation
depends on the angle of the U-joint.  For a straight joint the effect is
zero.  And for the small angles encountered in rear wheel drive it
is negligable.  However, it cannot be neglected in the angles encountered
in a fwd car. The angles are greater because the drive shafts are so much
shorter and the wheels also have to turn to steer.  So fwd cars use CV
joints so that their drive trains don't self-destruct.

The CV joints have ball-bearings inside of them, but these are not the
front wheel bearings.  The front wheel bearings are the ball|roller|
taper bearings that allow the front wheels to spin smoothly inside
the wheel housing.  

If the CV joint protective boot is cracked then grease can get out and 
water can get in and it would not be suprising if the joint wore out
in short order.  So called "split-boot" kits can be obtained which allow
you to replace the boot without taking off the drive shaft -- the boot
is split and you glue it back together after wraping it around the shaft.
I have one of these on my Rabbit and it seems to be holding up.  It is 
possible that your CV joints just need to be repacked with grease; you
might want to ask your mechanic about this.


oneill@lll-crg.arpa

>CV or constant velocity joints serve the same purpose in a front wheel
>drive car that U-joints serve on a rear wheel drive car.  That is, they 
>allow a flexible connection between the transaxle ( or transmission) and
>the drive wheels.  On a fwd car there is a CV joint at each end of each
>drive shaft.  One connects to the transaxle and the other to the wheel.
>They are called constant velocity joints because they provide for the
>linear transfer of angular velocity through the joint.  That is, if a shaft
>on one side if the CV joint is run at a constant 3000 RPM a wheel connected
>to the other side will run at a constant 3000 RPM regardless of the angle
>of the joint.  If you run a constant 3000 RPM into a U-joint you will get an
>output that only averages 3000 RPM but actually speeds up and slows down
>during a single revolution (play with the U-joints in a socket-wrench set
>and you will see what I mean).  This non-linear transfer of rotation
>depends on the angle of the U-joint.  For a straight joint the effect is
>zero.  And for the small angles encountered in rear wheel drive it
>is negligable.  However, it cannot be neglected in the angles encountered
>in a fwd car. The angles are greater because the drive shafts are so much
>shorter and the wheels also have to turn to steer.  So fwd cars use CV
>joints so that their drive trains don't self-destruct.


      if this is true, then how can I have universal joints at each 
front wheel on my solid front axel jeep cj-7 4x4 and my independent
front suspension bronco II 4x4 ?

> 
> > OK, what is the difference between a bearing an a CV joint.  My
> > 1981 Dodge Omni, (yup readers, the same one) has "worn front CV
> > joints".  On one of them (drivers side) the rubber bag that holds
> > the grease is ripped.  The grease can disappear.  ...
> 
> If the CV joint protective boot is cracked then grease can get out and 
> water can get in and it would not be suprising if the joint wore out
> in short order.  So called "split-boot" kits can be obtained which allow
> you to replace the boot without taking off the drive shaft -- the boot
> is split and you glue it back together after wraping it around the shaft.
> I have one of these on my Rabbit and it seems to be holding up.  It is 
> possible that your CV joints just need to be repacked with grease; you
> might want to ask your mechanic about this.

At least on the car in question, the CV joints don't seem to be particularly 
touchy about contamination/loss of lubricant.  As long as the boot is repaired
and the lubricant replaced within a reasonable period of time, the CV joint
doesn't seem to suffer too badly.  Changing the boot is not one of my favorite
jobs, though. 

I am curious about the so-called "split boot" kits mentioned above.  Anything
that eliminates the need to remove the drive shaft from the car certainly
sounds attractive to me.  Has anyone else had experience with these kits,
and/or know if they are applicable to late-model Chrysler FWD cars?