Tight bearings / New grease fitting

dave1

New member
Jul 23, 1998
460
0
0
I replaced my left front bearings last night. I had a very hard time=20
separating the bearing/hub assembly from the steering knuckle. The bearings=
=20
where pressed very tightly into the knuckle. I tried the slide hammer=20
approach as shown in the service manual but there is no way a slide hammer=
=20
would even budge them. I ended up using a wheel puller to press them out of=
=20
the knuckle. When I installed the new bearings, they where very tight going=
=20
in too. So tight in fact that when I pressed the new bearings in there=20
where a few tiny shavings, along the edge of the bearing race, where the=20
metal was shaved off of the surface of the inside bore of the steering=20
knuckle. I certainly did not like seeing that. I carefully cleaned out the=
=20
shavings before installing the seal. I am curious to know if anyone else=20
has had this problem. This is the first time I have done the bearings=20
myself so I am not sure what I should expect regarding fit.

When I had the assembly apart I stared at it for a while, trying to figure=
=20
out how to solve this "repack the bearings every 25K miles" problem. I can=
=20
certainly see why its a problem. There is very little room in the bearing=20
assembly for grease. The inner races are pressed tight together on the hub.=
=20
The outer races are separated by a precision spacer (used to set the=20
clearance). The seals are very close to the bearings. There is very little=
=20
room for grease.

What I came up with is as follows. I drilled a 3/32" grease passage in the=
=20
steering knuckle (between the tie-rod end and the upper ball joint)=20
positioned so that the grease will enter the area between the two outer=20
bearing races. I enlarged and tapped the outside end of the passage (1/4-28=
=20
x 3/8" deep) and installed a Zerk (grease) fitting. I drilled a 3/32" hole=
=20
in the spacer that separates the outer bearing races. I ground a flat area,=
=20
about .075" deep, around the hole in the spacer. The flat area is so the=20
two holes (the one in the knuckle and the one in the spacer) do not need to=
=20
be lined up perfectly. The flat space will allow the grease to flow, even=20
if the holes are offset a bit. When I pressed the bearings back into the=20
steering knuckle I was careful to position the spacer so that the hole in=20
the spacer will line up with the grease passage hole in the steering=
knuckle.

With this arrangement I should be able to inject fresh grease between the=20
bearings. The new grease will pass through the new grease passage, through=
=20
the hole in the spacer ring, through the roller cage, around the rollers=20
and seep out the seals. The new seals look like they are soft enough that=20
the old grease will easily seep out when new grease is added.

I am planning on giving it a few shots of Mobile-1 grease each time I=20
change the oil and lube the chassis. I guess only time will tell if this is=
=20
a good enough fix to keep the bearings lubricated properly. Changing the=20
bearings has been enough of a pain that I am willing to be the guinea pig=20
for what I hope is a long-term fix.

While I was making the modification I took some pics. If someone would like=
=20
to post them on their web site, let me know and I will pass them on when=20
get them developed.

By the way, Tom's bearing puller is a fine piece of work. It works great=20
and has been a real life saver. All that is missing from his tool set is a=
=20
good way to press the bearings out of the knuckle. After trying the slide=20
hammer approach for a while I gave up and had to improvise....

Also... For those of you who have bad things to say when you are trying to=
=20
get those three bolts back into the dust cover (between the rotor and the=20
steering knuckle) here is what I came up with. After cussing and suffering=
=20
while trying to get the first bolt inserted, I figured out a very useful=20
trick. Take a drum brake adjusting tool and a round magnet (the kind they=20
sell in bulk at the hardware store). Place the magnet on the brake=20
adjusting tool and the head of the bolt on the magnet. The magnet holds the=
=20
bolt so it is easy to use the tool to position the bolt in the hole and=20
then turn it with a screwdriver from the rear (assuming you have a=20
screwdriver slot cut in the threaded end of the bolt) while putting=20
pressure on the head of the bolt with the brake adjusting tool.

Dave
Ann Arbor, MI.
73 Sequoia (26'/455/EFI/HEI/160=B0)
 
I am interested in posting the pictures and notes --or pointing to them if
someone else puts them up. =20

Have you read Heinz stuff on this topic ??

http://www.bytedesigns.com/gmc/rambling.htm

How does yours compare to his, in zerk position, etc.

gene

>I replaced my left front bearings last night. I had a very hard time=20
>separating the bearing/hub assembly from the steering knuckle. The bearings=
=20
>where pressed very tightly into the knuckle. I tried the slide hammer=20
>approach as shown in the service manual but there is no way a slide hammer=
=20
>would even budge them. I ended up using a wheel puller to press them out of=
=20
>the knuckle. When I installed the new bearings, they where very tight going=
=20
>in too. So tight in fact that when I pressed the new bearings in there=20
>where a few tiny shavings, along the edge of the bearing race, where the=20
>metal was shaved off of the surface of the inside bore of the steering=20
>knuckle. I certainly did not like seeing that. I carefully cleaned out the=
=20
>shavings before installing the seal. I am curious to know if anyone else=20
>has had this problem. This is the first time I have done the bearings=20
>myself so I am not sure what I should expect regarding fit.
>
>When I had the assembly apart I stared at it for a while, trying to figure=
=20
>out how to solve this "repack the bearings every 25K miles" problem. I can=
=20
>certainly see why its a problem. There is very little room in the bearing=
=20
>assembly for grease. The inner races are pressed tight together on the hub.=
=20
>The outer races are separated by a precision spacer (used to set the=20
>clearance). The seals are very close to the bearings. There is very little=
=20
>room for grease.
>
>What I came up with is as follows. I drilled a 3/32" grease passage in the=
=20
>steering knuckle (between the tie-rod end and the upper ball joint)=20
>positioned so that the grease will enter the area between the two outer=20
>bearing races. I enlarged and tapped the outside end of the passage (1/4-28=
=20
>x 3/8" deep) and installed a Zerk (grease) fitting. I drilled a 3/32" hole=
=20
>in the spacer that separates the outer bearing races. I ground a flat area,=
=20
>about .075" deep, around the hole in the spacer. The flat area is so the=20
>two holes (the one in the knuckle and the one in the spacer) do not need to=
=20
>be lined up perfectly. The flat space will allow the grease to flow, even=
=20
>if the holes are offset a bit. When I pressed the bearings back into the=20
>steering knuckle I was careful to position the spacer so that the hole in=
=20
>the spacer will line up with the grease passage hole in the steering=
knuckle.
>
>With this arrangement I should be able to inject fresh grease between the=
=20
>bearings. The new grease will pass through the new grease passage, through=
=20
>the hole in the spacer ring, through the roller cage, around the rollers=20
>and seep out the seals. The new seals look like they are soft enough that=
=20
>the old grease will easily seep out when new grease is added.
>
>I am planning on giving it a few shots of Mobile-1 grease each time I=20
>change the oil and lube the chassis. I guess only time will tell if this is=
=20
>a good enough fix to keep the bearings lubricated properly. Changing the=
=20
>bearings has been enough of a pain that I am willing to be the guinea pig=
=20
>for what I hope is a long-term fix.
>
>While I was making the modification I took some pics. If someone would like=
=20
>to post them on their web site, let me know and I will pass them on when=20
>get them developed.
>
>By the way, Tom's bearing puller is a fine piece of work. It works great=20
>and has been a real life saver. All that is missing from his tool set is a=
=20
>good way to press the bearings out of the knuckle. After trying the slide=
=20
>hammer approach for a while I gave up and had to improvise....
>
>Also... For those of you who have bad things to say when you are trying to=
=20
>get those three bolts back into the dust cover (between the rotor and the=
=20
>steering knuckle) here is what I came up with. After cussing and suffering=
=20
>while trying to get the first bolt inserted, I figured out a very useful=20
>trick. Take a drum brake adjusting tool and a round magnet (the kind they=
=20
>sell in bulk at the hardware store). Place the magnet on the brake=20
>adjusting tool and the head of the bolt on the magnet. The magnet holds the=
=20
>bolt so it is easy to use the tool to position the bolt in the hole and=20
>then turn it with a screwdriver from the rear (assuming you have a=20
>screwdriver slot cut in the threaded end of the bolt) while putting=20
>pressure on the head of the bolt with the brake adjusting tool.
>
>
>Dave
>Ann Arbor, MI.
>73 Sequoia (26'/455/EFI/HEI/160=B0)
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
>I am interested in posting the pictures and notes --or pointing to them if
>someone else puts them up.
>
>Have you read Heinz stuff on this topic ??
>http://www.bytedesigns.com/gmc/rambling.htm
>How does yours compare to his, in zerk position, etc.

No, I had not read his page. But I did put my grease fitting in the same=20
location. He says that he doesn't know what they did inside when they added=
=20
the grease fitting. I would be curious to know why he replaced his bearings=
=20
a couple times after the grease fitting was added. Was it preventative=20
maintenance or because of a failure of some type. One comment that he did=20
make was that he was told not to use much pressure when adding grease. For=
=20
this to work I expect that I will have to add enough grease so that the old=
=20
grease will be expelled around the seals. The idea is to replace the old=20
grease with new, not just add more.

Dave
Ann Arbor, MI.
73 Sequoia (26'/455/EFI/HEI/160=B0)
 
I think even on the wallace Hubs (also on my page) which also had a zerk
there, they recommended not forcing the grease past the seals. The
implication is that the seals would leak after that....

gene

>>I am interested in posting the pictures and notes --or pointing to them if
>>someone else puts them up.
>>
>>Have you read Heinz stuff on this topic ??
>>http://www.bytedesigns.com/gmc/rambling.htm
>>How does yours compare to his, in zerk position, etc.
>
>No, I had not read his page. But I did put my grease fitting in the same=20
>location. He says that he doesn't know what they did inside when they added=
=20
>the grease fitting. I would be curious to know why he replaced his bearings=
=20
>a couple times after the grease fitting was added. Was it preventative=20
>maintenance or because of a failure of some type. One comment that he did=
=20
>make was that he was told not to use much pressure when adding grease. For=
=20
>this to work I expect that I will have to add enough grease so that the old=
=20
>grease will be expelled around the seals. The idea is to replace the old=20
>grease with new, not just add more.
>
>
>Dave
>Ann Arbor, MI.
>73 Sequoia (26'/455/EFI/HEI/160=B0)
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Also the very real possibility of pushing out the inner bearing seal, which
is not a very tight fit in the knuckle due to its large diameter. If not
detected, the resulting contamination and loss of grease would bring on
bearing failure almost immediately.

Patrick

>
> At one time, Wallace made a triple bearing hub which had a
> grease fitting. Someone asked Ken Thoma why you couldn't
> just put a fitting on the standard hub as you have done.
> Ken felt that you would be just pushing clean grease onto
> older grease and not properly cleaning the bearings. He
> also stated that overfilling with grease would increase
> the heat on the bearings and potentially cause bearing
> failure quicker. Apparently too much grease is as big a
> problem as too little.
 
I also sat in on Ken Tomas bearing seminar, he hit on the three bearing =
and Zerk fitting controversy.
Here are my feelings.

>When I had the assembly apart I stared at it for a while, trying to figu=
re=20
>out how to solve this "repack the bearings every 25K miles" problem. I c=
an=20
>certainly see why its a problem. There is very little room in the bearin=
g=20
>assembly for grease. The inner races are pressed tight together on the h=
ub.=20
>The outer races are separated by a precision spacer (used to set the=20
>clearance). The seals are very close to the bearings. There is very litt=
le=20
>room for grease.=20
>=20
>What I came up with is as follows. I drilled a 3/32" grease passage in t=
he=20
>steering knuckle (between the tie-rod end and the upper ball joint)=20
>positioned so that the grease will enter the area between the two outer=20
>bearing races. I enlarged and tapped the outside end of the passage (1/4=
- -28=20
>x 3/8" deep) and installed a Zerk (grease) fitting. I drilled a 3/32" ho=
le=20
>in the spacer that separates the outer bearing races. I ground a flat ar=
ea,=20
>about .075" deep, around the hole in the spacer. The flat area is so the=
=20
>two holes (the one in the knuckle and the one in the spacer) do not need=
to=20
>be lined up perfectly. The flat space will allow the grease to flow, eve=
n=20
>if the holes are offset a bit. When I pressed the bearings back into the=
=20
>steering knuckle I was careful to position the spacer so that the hole i=
n=20
>the spacer will line up with the grease passage hole in the steering knu=
ckle.=20
>=20
>With this arrangement I should be able to inject fresh grease between th=
e=20
>bearings. The new grease will pass through the new grease passage, throu=
gh=20
>the hole in the spacer ring, through the roller cage, around the rollers=
=20
>and seep out the seals. The new seals look like they are soft enough tha=
t=20
>the old grease will easily seep out when new grease is added.=20

This is exactly what Walter Wallace had in mind when he added the Zerk fi=
tting to his Bearing sets.
He showed me how to grease the front wheel-bearings every 20K miles.
Jack up the wheel to unload the bearing, loosen the spindle nut and pump =
in several (2) strokes of (what he used at his time was) Mystic grease. I=
t's not like having the old grease spin around in an enclosed brake-drum.=
If you don't get carried away, there should be no damage to the grease s=
eal.
Whipe off the old grease, re-tourque the spindle nut and you'r done.

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