Knuckle Gotchas

nate chase

New member
Apr 26, 1999
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Welp, been waiting a month but looks like I didn't get a puller from Tom's
first batch. Now my uncles drivers side bearing went bad yesterday (when I
was with him no less... geez starting to think GMC and me don't go together
well). Anyways, Is there a write up on pulling the knuckles somewhere like
the one I did on the steering box? I looked at Gene's site and Arch's stuff
shows them mounted... then poof unmounted. I can read the manual but thought
if there were some gotchas the manual doesn't talk about it would be nice to
know. We need to get these knuckles to someone that has a puller locally and
can't keep waiting for Tom's puller.

Nate '75GB (now with two broken coaches) Omaha
 
>
> Is there a write up on pulling the knuckles somewhere like
> the one I did on the steering box?

Nate,

I posted the procedure for disassembling and reassembling the hubs and
knuckles using a Ken Thoma tool set on my site.

Patrick
- --
Patrick Flowers
Mailto:patrick

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
>, 7 Sep 1999 16:09:31 -0500
>From: "Nate Chase"
.......snip......
>if there were some gotchas the manual doesn't talk about it would be nice to
>know.
.......snip......

Nate, I just got done putting the whole shebang back together here, so
everything is still fresh in my mind (what's left of it, anyways, LOL)

* Break 1 1/2" axle nut and lug nuts loose before jacking the coach up &
removing wheel & tire.

* Block rear wheel before jacking front corner up

* Support the coach at where the front frame is bolted to the side frame
rail.

* Use upended bucket or a milk crate for setting the caliper on once you
get it off.

* Careful with removing those old rusty cotter keys - soak liberally in
penetrant & good luck (I still had to break off the lower ball joint
key and drill it out, not fun)
~~~~~~~~~~~

* Remove caliper and place it on upended bucket behind the control arms
near the frame. The threads for the caliper guide pins (3/8 socket head)
are on the inside knuckle "ears" should you care to shoot penetrant there.
I ended up heating the thread area with a propane torch even with penetrant
and big vise grips in order to remove mine)

* Back off axle nut so just a few threads are engaged.

* Remove tie rod joint & lower ball joint with appropriate tool. I used a
puller with a 2 1/2" throat and a 1 1/2" opening. Rotate tie rod end up
out of the way. Do not lose the lower ball joint seal, which will fall off.

* Back off upper ball joint castellated nut but *do not remove* yet.

* Break the joint loose via crowbar pressure between the upper control arm
and knuckle while striking the knuckle at the ball joint seat area with a
big hammer.

* Knuckle will drop down to loosened castellated nut.

* Remove the nut and brake hose support bracket.

* Remove axle nut and the knuckle & hub assy is out

The rest of the procedure is shown on the web, as you've noted. Once
you've removed the cover plate between the hub and knuckle (3 bolts) you
can pop the knuckle off using a couple of crowbars if it doesn't want to
come off.

You may want to get some new 3/8-16 x 3/4" grade 5 bolts for the above
cover as the heads are usually buggered up from wrench slippage. Hacksaw
screwdriver slots on the ends as shown on the web. Also new caliper guide
pins ($3.59 ea @ Autozone) may be required.

Now would be a good time to replace the CV boot if it shows any signs of
deterioration. Ask yourself if you want to go through all this again to
replace it (I replaced mine). The boot kit will come with grease and bands
for around $10. I used Mobil One grease instead.

** Remember to make sure the outer (towards the rotor) grease seal is
seated after dropping the knuckle onto the new bearing set **

Re-assembly is straightforward although having an extra pair of hands sure
helps *a lot* in lining up the stub axle and lower ball joint without
nicking the inner bearing seal. Once lower ball joint nut is started
enough to hold, shove the assy onto the stub axle far enough to start the
axle nut & take a break. Wash rotor with brake cleaner.

***Bend the upper ball joint cotter key ends so that they will remain above
the end of the joint, precluding any possible contact with the CV boot.***

The 3/16 x 1 1/2" axle nut cotter key requires a bit of finagling to
install. File a radius on the ends and curve it gently until you get it
well started. Then you can pry it in the rest of the way using a large
screwdriver.

That's all I can think off - HTH


As always, best regards.

~ Ritch & Betty Hwang ~ Clarkston, MI ~ mailto:rhwang
Visit our home page ~ http://www.concentric.net/~rhwang/
~ =^..^= Trinket ~ the shy Persian kitty ~
~ 76 GMC Birchaven ~ FMCA F249339 ~ RVClub 00930 ~ ICQ# 6408591~
(B}>
 
Ritch,
Having said all that, would you do it again? Or would you consider
having it done, while you watch, sipping on a cool beverage?
Of course you're retired and have some extra time on your hands ?
Richard Waters '76 PB, Troy, MI

* Break 1 1/2" axle nut and lug nuts loose before jacking the coach up &

> removing wheel & tire.
>
> * Block rear wheel before jacking front corner up
>
> * Support the coach at where the front frame is bolted to the side frame
> rail.
>
> * Use upended bucket or a milk crate for setting the caliper on once you
> get it off.
>
> * Careful with removing those old rusty cotter keys - soak liberally in
> penetrant & good luck (I still had to break off the lower ball joint
> key and drill it out, not fun)
> ~~~~~~~~~~~
>
> * Remove caliper and place it on upended bucket behind the control arms
> near the frame. The threads for the caliper guide pins (3/8 socket head)
> are on the inside knuckle "ears" should you care to shoot penetrant there.
> I ended up heating the thread area with a propane torch even with penetrant
> and big vise grips in order to remove mine)
>
> * Back off axle nut so just a few threads are engaged.
>
> * Remove tie rod joint & lower ball joint with appropriate tool. I used a
> puller with a 2 1/2" throat and a 1 1/2" opening. Rotate tie rod end up
> out of the way. Do not lose the lower ball joint seal, which will fall off.
>
> * Back off upper ball joint castellated nut but *do not remove* yet.
>
> * Break the joint loose via crowbar pressure between the upper control arm
> and knuckle while striking the knuckle at the ball joint seat area with a
> big hammer.
>
> * Knuckle will drop down to loosened castellated nut.
>
> * Remove the nut and brake hose support bracket.
>
> * Remove axle nut and the knuckle & hub assy is out
>
> The rest of the procedure is shown on the web, as you've noted. Once
> you've removed the cover plate between the hub and knuckle (3 bolts) you
> can pop the knuckle off using a couple of crowbars if it doesn't want to
> come off.
>
> You may want to get some new 3/8-16 x 3/4" grade 5 bolts for the above
> cover as the heads are usually buggered up from wrench slippage. Hacksaw
> screwdriver slots on the ends as shown on the web. Also new caliper guide
> pins ($3.59 ea @ Autozone) may be required.
>
> Now would be a good time to replace the CV boot if it shows any signs of
> deterioration. Ask yourself if you want to go through all this again to
> replace it (I replaced mine). The boot kit will come with grease and bands
> for around $10. I used Mobil One grease instead.
>
> ** Remember to make sure the outer (towards the rotor) grease seal is
> seated after dropping the knuckle onto the new bearing set **
>
> Re-assembly is straightforward although having an extra pair of hands sure
> helps *a lot* in lining up the stub axle and lower ball joint without
> nicking the inner bearing seal. Once lower ball joint nut is started
> enough to hold, shove the assy onto the stub axle far enough to start the
> axle nut & take a break. Wash rotor with brake cleaner.
>
> ***Bend the upper ball joint cotter key ends so that they will remain above
> the end of the joint, precluding any possible contact with the CV boot.***
>
> The 3/16 x 1 1/2" axle nut cotter key requires a bit of finagling to
> install. File a radius on the ends and curve it gently until you get it
> well started. Then you can pry it in the rest of the way using a large
> screwdriver.
>
> That's all I can think off - HTH
>
 
Forgot to mention I used silicon grease on cotter key and caliper pin
installs to ease future removal...

>, 7 Sep 1999 16:09:31 -0500
>From: "Nate Chase"
.......snip......
>if there were some gotchas the manual doesn't talk about it would be nice to
>know.
.......snip......
As always, best regards.

~ Ritch & Betty Hwang ~ Clarkston, MI ~ mailto:rhwang
Visit our home page ~ http://www.concentric.net/~rhwang/
~ =^..^= Trinket ~ the shy Persian kitty ~
~ 76 GMC Birchaven ~ FMCA F249339 ~ RVClub 00930 ~ ICQ# 6408591~
(B}>
 
Patrick,
Thanks a ton, guy!!!! I'll take a look see when I get home tonight.

Nate '75GB (Beautiful, clear 70 degree Fall Day in) Omaha


Nate,

I posted the procedure for disassembling and reassembling the hubs and
knuckles using a Ken Thoma tool set on my site.

Patrick
- - --
Patrick Flowers
Mailto:patrick

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Ritch,
Thanks a million, guy!!! Sure filled in those nasty blank spaces for me.
Hope Gene catches your write up for future reference as well.

Nate '75GB (Now better informed) Omaha


Date: Wed, 08 Sep 1999 00:07:54 -0400
From: Ritch Hwang
Subject: GMC: Knuckle Gotchas

>, 7 Sep 1999 16:09:31 -0500
>From: "Nate Chase"
.......snip......
>if there were some gotchas the manual doesn't talk about it would be nice
to
>know.
.......snip......

Nate, I just got done putting the whole shebang back together here, so
everything is still fresh in my mind (what's left of it, anyways, LOL)
 
Hi Richard,

I don't mind working on anything that allows me to buy more *tools* LOL.

But seriously it is a demanding project. Half of your time will be spent
cleaning stuff up while it's apart and the knuckle/bearing assy is no fun
to wrassle with, especially if you only weigh 130 lbs or so. I only hope
I'm physically able to do it again a few years from now. My viewpoint is
that if I do it myself, I *know* what's been done, and how it was done. I
can also address those small details that a hired mech may ignore. Also, I
now have a baseline in which *all* of the bearings were done by yours truly
using the best advice from the GMCnet, so I don't have to worry about them
for a while.

Cold beverages were imbibed on *frequent* breaks, especially in this hot &
humid Michigan summer, grin.

Re being retired: While being on fixed income is no fun, life is a *lot*
more relaxed. Whereas I used to get up and be out the door in 30 minutes,
a couple of hours are now consumed puttering around making breakfast,
checking email, playing with the cat, reading the paper & etc. *Bliss*.
And since Betty's retired we don't know what day it is unless we look at
the newspaper ;o)))

>Subject: Re: GMC: Knuckle Gotchas
>
>Ritch,
>Having said all that, would you do it again? Or would you consider
>having it done, while you watch, sipping on a cool beverage?
>Of course you're retired and have some extra time on your hands ?
>Richard Waters '76 PB, Troy, MI

As always, best regards.

~ Ritch & Betty Hwang ~ Clarkston, MI ~ mailto:rhwang
Visit our home page ~ http://www.concentric.net/~rhwang/
~ =^..^= Trinket ~ the shy Persian kitty ~
~ 76 GMC Birchaven ~ FMCA F249339 ~ RVClub 00930 ~ ICQ# 6408591~
(B}>
 
Arch,
My uncle's coach ('73 PD 23') sat for 6 years and needed A LOT of work.
Maintenance unknown. He got it started and has been working on it quite a
bit. Really starting to shape up. Been driving it locally alot (probably
1000 miles). Since neither he nor I had a puller for the wheel bearings I
ordered one from Tom about a month ago (also ordered the OTC927 today!). We
knew we'd need it just a matter of time. Looks like the time's up for his
drivers side front. Really making some nasty noise Sunday and it happened
FAST too. Probably 25 miles from no noise to a very loud thunk at every tire
rotation. New tires and we saw no bulges or broken cords. Told him to try
the wheel on the back to see if it moves the problem. Could be a CV joint
but I doubt it since my experience is they go slowly and usually only thunk
when you turn corners. Bet money on the bearing but we'll see...

Nate '75GB (Another crystal clear 75 degree day) Omaha
 
Nate did you get the OTC927 yet? Without it the bearing puller is not usable.

>Arch,
> My uncle's coach ('73 PD 23') sat for 6 years and needed A LOT of work.
>Maintenance unknown. He got it started and has been working on it quite a
>bit. Really starting to shape up. Been driving it locally alot (probably
>1000 miles). Since neither he nor I had a puller for the wheel bearings I
>ordered one from Tom about a month ago (also ordered the OTC927 today!). We
>knew we'd need it just a matter of time. Looks like the time's up for his
>drivers side front. Really making some nasty noise Sunday and it happened
>FAST too. Probably 25 miles from no noise to a very loud thunk at every tire
>rotation. New tires and we saw no bulges or broken cords. Told him to try
>the wheel on the back to see if it moves the problem. Could be a CV joint
>but I doubt it since my experience is they go slowly and usually only thunk
>when you turn corners. Bet money on the bearing but we'll see...
>
>Nate '75GB (Another crystal clear 75 degree day) Omaha
>
>
>
 
Tom,
I just ordered the OTC927 this AM. They said it should be here in a few
days (I hope). It'll be a race to see which half shows up first! Thanks for
the follow up, guy...

Nate '75GB (just waiting by the mailbox in) Omaha


>Nate '75GB (Another crystal clear 75 degree day) Omaha