<VV> Rear wheel bearing greasing options / observations

[Tony Underwood]

At 10:47 hours 02/16/2005, J R Read_HML wrote:
>Tony... Unfortunately the tech guide says to drill utill you are through..


And this can get you into trouble if you're not very careful and maybe a 
little lucky.

Perhaps someone in a future printing might consider editing this 
article...?


For the sake of argument, the hole shouldn't be drilled all the way 
through.   This is just asking for trouble.   Stop after you "strike air", 
when you  see that the bit tip has just started poking through... go no 
farther.   Nothing is likely to have gotten inside the hub this way.   Then 
break out the punch and wallow the "thin spot" out.    Tapping the hole is 
twitchy, although I've used a greased up tap and managed to keep most of 
the debris on the tap and the remainder was blown out following the  bath 
in brake klene.   A bottoming tap might work even better.    *This*, if you 
install a grease fitting...

Now:   If you do this up with some thoughtfulness, a zerk fitting is NOT 
necessary unless you feel it *must* be there.    Getting grease into the 
bearing can be done with one of those cute nozzles on the end of the grease 
gun that allows you to squirt  grease into the bearing hub straight through 
the hole.    The hole can be plugged afterwards with your choice of fixes, 
from epoxy putty to a rubber cinch plug to whatever.

Think clean.   A can of brake-klene is cheap and it's not a crime to use 
the whole can on a hub.  And blow the stuff out with air, bigtime.  Then 
repeat.   repeat again.  The seals will expand to allow the stuff to exit 
the hub if they're in any sort of shape at all, and they usually haven't 
failed because they don't get *that* hot (or shouldn't) and they don't get 
worked very hard.

Matt N.  explained the "grease principle" pretty well, a while back:

It only takes a very small amount of grease on the rollers to actually do 
the job.

Most of the extra is wasted and just sits there outside the races or on the 
race cage or in the hub housing doing nothing.   If you squirt an "educated 
guess" amount of grease into the hole in the hub, "aimed" with the nozzle 
(works better if you have a "bent nozzle" to allow you to squirt it where 
it should go), and chase it with the air, it's gonna blow the grease 
through the bearings without clumping up in a wad inside the hub.    Less 
waste and the grease gets to where it needs to be.   Spinning the hub 
distributes grease around the races of the bearings etc and all is well.


Now, some of it is gonna weep out since a bit is gonna end up outside the 
bearing race and against the grease seals seeing as how if the air is gonna 
blow the grease into the bearing it's also gonna blow some past the bearing 
and against that seal.  The weep behind the backing plate is moot since it 
just oils up the back of the yoke but weeping grease out the front can get 
on the brakes.   You have to check a time or two for seepage coming out of 
the front hub seal around the axle stub and clean off as 
necessary.    Again, brake-klene and compressed air.   After one or two 
checks/cleanings (usually takes no more than a week's time of running) it 
should stop and not be a problem anymore.  If you're lucky there won't be 
*any* seepage to possibly foul the brake shoes.     If you cram the hub 
full of grease, expect it  to end up on the brakes.


Sure, the best way is to remove and dismantle the hubs and hand-clean and 
pack the bearings and reassemble etc.


Ask anyone who's done this if it's an easy job.    It's for that reason 
that the hole-in-the-hub trick got cooked up to begin with.    But it only 
works if you're careful and you have a good idea of what you're doing and 
how what you're doing does what it does...

...and, if the bearings aren't  already shot.   Greasing a bad bearing 
won't get you very far.


I do NOT recommend trying this if you have any doubts as to how to do 
it.   But if you know what's going on inside the hubs and you have the 
necessary stuff on hand and you are *not* doing it for a customer while 
working out of a commercial business (avoid liability issues), give it a 
shot, no pun.


This is the sort of thing that a serious do-it-yourself backyard mechanic 
might do; the sort of guy who would also change his own u-joints and do his 
own brake jobs and tune-ups etc.  but might stop short of dismantling the 
rear suspension of the car to remove the hubs and attempt to pull them 
apart.




Bob Coffin mentioned having to follow up behind another shop that did the 
hub trick, to correct problems incurred.   They (the other shop) shouldn't 
have done it.  You cannot really guarantee the hub trick for a customer if 
you're in a working shop environment doing it for a living.    But you CAN 
do it to your own car and get good results without problems IF you do it 
right...  since if it doesn't work out, there's gonna be nobody to blame 
afterwards but yourself and there's no irate customer to berate your 
business.   If the hub trick works out OK, you're ahead of the game.   If 
not...  that's when you go to the back-up Plan-B and pick up a pair of 
rebuilt hubs from a vendor.

...then you can attempt to pull the old hubs apart and see what fun it is 
to rebuild one.

They're expensive for a reason... ;)     So,  if they're almost 40 years 
old and your daily driver's rear bearings are still running smooth but 
you're starting to wonder, and IF you have the tools on hand (including a 
compressed air source) and a tub of premium grade synthetic hi-temp wheel 
bearing grease, feel free.



tony..