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| [GMCnet] a-arm adjuster cam, initial settings? [message #130562] |
Fri, 17 June 2011 10:21  |
KB
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Registered: September 2009
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So, if you've pulled the upper a-arm, replaced bushings, etc,
where do you initially set the upper a-arm adjustment cams?
I was thinking two likely possibilities:
a) with maximum caster (ie, ball joint as far to the rear as possible).
b) in the middle of the adjustment slots, kind of a "neutral" seeming position.
In either case, they have to be adjusted more to set camber so maybe it
doesn't matter. And it's going right to an alignment shop once it's
back together anyway.
What do experienced people do with this first setting of the cams?
thanks,
Karen
1973 23'
1975 26'
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1975 26'
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130573 is a reply to message #130562] |
Fri, 17 June 2011 11:03  |
Wayne
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Registered: August 2004
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I installed the offset bushing in the rear only of the upper arm. As you can't get enough caster, I set initial MAX caster and then set camber to "0" and toe in to "0". I probably would not do it the same if I had of used offset in front also.
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130583 is a reply to message #130562] |
Fri, 17 June 2011 11:50 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Since you're apparently only going a few miles, it doesn't really
matter much. But, I'd use an ordinary carpenter's level (since I was
practically born with one and I assume you don't have a Caster/Camber
gauge) to set the camber to 0* with as much caster as you eyeball
shows on the eccentrics.
If anything's critical for the short trip, it's the toe-in -- set that
to near 0" with a tape measure between the front & rear of the tires.
JMHO,
Ken H.
On Fri, Jun 17, 2011 at 11:21 AM, KB <kab7@sonic.net> wrote:
> So, if you've pulled the upper a-arm, replaced bushings, etc,
> where do you initially set the upper a-arm adjustment cams?
...
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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] a-arm adjuster cam, initial settings? [message #130641 is a reply to message #130562] |
Fri, 17 June 2011 18:35 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
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Karen,
Set the eccentric with the bolt as far from the frame as possible. On the
passenger side the bolt would be at 3:00 and on the drivers side it would be
at 9:00.
That's what John Sharpe and I did when we I installed Dave Lenzi's offset
upper control arms in Double Trouble. I had to drive about 20 miles to the
Beasley's truck alignment and that was no problems. When I got to the truck
alignment shop and the tech started the alignment I had 6 degrees of caster.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of KB
Sent: Saturday, June 18, 2011 1:22 AM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] a-arm adjuster cam, initial settings?
So, if you've pulled the upper a-arm, replaced bushings, etc,
where do you initially set the upper a-arm adjustment cams?
I was thinking two likely possibilities:
a) with maximum caster (ie, ball joint as far to the rear as possible).
b) in the middle of the adjustment slots, kind of a "neutral" seeming
position.
In either case, they have to be adjusted more to set camber so maybe it
doesn't matter. And it's going right to an alignment shop once it's
back together anyway.
What do experienced people do with this first setting of the cams?
thanks,
Karen
1973 23'
1975 26'
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130647 is a reply to message #130562] |
Fri, 17 June 2011 19:17 |
C Boyd
Messages: 2629
Registered: April 2006
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| KB wrote on Fri, 17 June 2011 11:21 |
So, if you've pulled the upper a-arm, replaced bushings, etc,
where do you initially set the upper a-arm adjustment cams?
I was thinking two likely possibilities:
a) with maximum caster (ie, ball joint as far to the rear as possible).
b) in the middle of the adjustment slots, kind of a "neutral" seeming position.
In either case, they have to be adjusted more to set camber so maybe it
doesn't matter. And it's going right to an alignment shop once it's
back together anyway.
What do experienced people do with this first setting of the cams?
thanks,
Karen
1973 23'
1975 26'
|
From my experience with initial settings with upper rear offset bushing.. I set the rear bolt as far in as the A arm will go. I then try to set the front bolt on the ground on wet garbage bags to where the wheel is vertical with a level, it usually is right at 1/2 way. I Set toe at 0 last. When taken to alignment shop the camber has been within 1-2* sometimes closer. The caster has always been more on the drivers side?? Usually 2 1/2 on Pass side and 3 1/2 on drivers side.
C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130681 is a reply to message #130562] |
Fri, 17 June 2011 23:52 |
KB
Messages: 1262
Registered: September 2009
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Actually, this gets me thinking (always dangerous!): Do these beasts even need to
go to an alignment shop? Camber and toe look fairly straightforward to measure and set.
Especially if you're going for 0 on both -- there are no angles to compute.
Caster is harder, but if you're only adjusting the front cam and taking what
you get, you don't even have to worry about caster.
What am I missing (other than a lot of very expensive alignment equipment)?
thanks,
Karen
1973 23'
1975 26'
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1975 26'
San Jose, CA
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130701 is a reply to message #130681] |
Sat, 18 June 2011 06:11 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Nothing. Especially the "very expensive alignment equipment". I have
about $75 in mine, including the always-handy digital level:
http://www.gmcmhphotos.com/photos/showgallery.php?cat=5634
Those jigs make camber measurement trivially simple. And with the
addition of 60" beams clamped to the horizontal members, toe can be
measured accurately with a tape measure between them (the 60" beams
provide double accuracy vs measuring at the tire).
Even caster is not difficult to determine. The digital level can be
zero'd at one 20* turn angle and then read at the opposite 20*
position. That reading multiplied by 1.4 should give the caster.
And, as you suggested, since we're really only interested in getting
as much as possible, that value isn't really important -- what we
really want is to the get the caster close to the same on both sides.
Considering that most of our driving is usually on nearly-flat
highways, I'm not even very concerned about setting a road-crown bias.
I'm not, by any stretch of the imagination, a wheel alignment expert,
but Rob and I aligned my coach as well as it's ever been done.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Sat, Jun 18, 2011 at 12:52 AM, KB wrote:
> Actually, this gets me thinking (always dangerous!): Do these beasts even need to
> go to an alignment shop? Camber and toe look fairly straightforward to measure and set.
> Especially if you're going for 0 on both -- there are no angles to compute.
> Caster is harder, but if you're only adjusting the front cam and taking what
> you get, you don't even have to worry about caster.
>
> What am I missing (other than a lot of very expensive alignment equipment)?
>
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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] a-arm adjuster cam, initial settings? [message #130710 is a reply to message #130701] |
Sat, 18 June 2011 09:14 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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and
here is another set of "home" alignment directions
http://goo.gl/CKHwt
gene
Nothing. Especially the "very expensive alignment equipment". I have
> about $75 in mine, including the always-handy digital level:
>
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=5634
>
> Those jigs make camber measurement trivially simple. And with the
> addition of 60" beams clamped to the horizontal members, toe can be
> measured accurately with a tape measure between them (the 60" beams
> provide double accuracy vs measuring at the tire).
>
> Even caster is not difficult to determine. The digital level can be
> zero'd at one 20* turn angle and then read at the opposite 20*
> position. That reading multiplied by 1.4 should give the caster.
> And, as you suggested, since we're really only interested in getting
> as much as possible, that value isn't really important -- what we
> really want is to the get the caster close to the same on both sides.
> Considering that most of our driving is usually on nearly-flat
> highways, I'm not even very concerned about setting a road-crown bias.
>
> I'm not, by any stretch of the imagination, a wheel alignment expert,
> but Rob and I aligned my coach as well as it's ever been done.
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI+ & EBL
> www.gmcwipersetc.com
>
>
>
> On Sat, Jun 18, 2011 at 12:52 AM, KB wrote:
> > Actually, this gets me thinking (always dangerous!): Do these beasts
> even need to
> > go to an alignment shop? Camber and toe look fairly straightforward to
> measure and set.
> > Especially if you're going for 0 on both -- there are no angles to
> compute.
> > Caster is harder, but if you're only adjusting the front cam and taking
> what
> > you get, you don't even have to worry about caster.
> >
> > What am I missing (other than a lot of very expensive alignment
> equipment)?
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130711 is a reply to message #130701] |
Sat, 18 June 2011 09:21 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Ken,
That makes two of us!
However, considering that we could see the wheel on the drivers side leaning
SERIOUSLY out at the top (explained by the fact that the nuts on the
eccentrics on that side were not torqued properly) I'd say we did a LOT
better job than the last guy! ;-)
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Ken Henderson
I'm not, by any stretch of the imagination, a wheel alignment expert,
but Rob and I aligned my coach as well as it's ever been done.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130721 is a reply to message #130701] |
Sat, 18 June 2011 10:17 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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:
> Nothing. Especially the "very expensive alignment equipment". I have
> about $75 in mine, including the always-handy digital level:
>
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=5634
>
> Those jigs make camber measurement trivially simple. And with the
> addition of 60" beams clamped to the horizontal members, toe can be
> measured accurately with a tape measure between them (the 60" beams
> provide double accuracy vs measuring at the tire).
>
> Even caster is not difficult to determine. The digital level can be
> zero'd at one 20* turn angle and then read at the opposite 20*
> position. That reading multiplied by 1.4 should give the caster.
> And, as you suggested, since we're really only interested in getting
> as much as possible, that value isn't really important -- what we
> really want is to the get the caster close to the same on both sides.
> Considering that most of our driving is usually on nearly-flat
> highways, I'm not even very concerned about setting a road-crown bias.
>
> I'm not, by any stretch of the imagination, a wheel alignment expert,
> but Rob and I aligned my coach as well as it's ever been done.
>
> Ken H.
>
and to get them all on one page
http://www.gmcmidwestclassics.org/Web%20pages/align.htm
gene
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI+ & EBL
> www.gmcwipersetc.com
>
>
>
> On Sat, Jun 18, 2011 at 12:52 AM, KB wrote:
> > Actually, this gets me thinking (always dangerous!): Do these beasts
> even need to
> > go to an alignment shop? Camber and toe look fairly straightforward to
> measure and set.
> > Especially if you're going for 0 on both -- there are no angles to
> compute.
> > Caster is harder, but if you're only adjusting the front cam and taking
> what
> > you get, you don't even have to worry about caster.
> >
> > What am I missing (other than a lot of very expensive alignment
> equipment)?
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130759 is a reply to message #130681] |
Sat, 18 June 2011 14:27 |
KB
Messages: 1262
Registered: September 2009
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Ooooh, this this is so cool! I've had such bad experiences with mechanics
that now I do all the (simpler) work in self defense.
Even just doing this 1-ton install, I've found and corrected really sloppy
mistakes that some "pro" did before me. And I know pros did it because I have
receipts from the previous owners!
thanks!
Karen
1973 23'
1975 26'
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1975 26'
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130762 is a reply to message #130760] |
Sat, 18 June 2011 15:27 |
James Hupy
Messages: 6806
Registered: May 2010
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Karen, not much except for an initial setting. You really should have the
coach at ride height on all four corners, and with properly inflated tires
resting on swivel pads of some kind before any "exact" measurements are
undertaken. Close only counts when you are playing with horseshoes or hand
grenades, and wheel alignment is kind of an exacting undertaking. There are
real alignment experts in the GMC community, many of which are glad to share
tips with you.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sat, Jun 18, 2011 at 12:33 PM, KB <kab7@sonic.net> wrote:
> Is there any benefit to initially checking toe from the rotor faces while
> the beast is
> still jacked up with the wheels off? Or should I not bother until the
> wheels
> are on the ground? I figure camber will change a lot when it hits the
> ground,
> but not sure about toe.
>
> thanks,
> Karen
> 1973 23'
> 1975 26'
>
>
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #130774 is a reply to message #130760] |
Sat, 18 June 2011 17:45 |
KB
Messages: 1262
Registered: September 2009
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> be sure you use the unloader to set the height.
>
> remember one of your pork-chops may be stripped, since the PO had an extra
> nut on it. --- indicates someone stripped the threads trying to level the
> coach.
Thanks Gene. I cleaned and inspected the bolts and nuts and they looked ok, but
replaced them just to be sure (spare coaches are good to have). I think
this may have been an alignment shop issue since I've seen that other vehicle
specifications call for using loctite, etc.
While I can see (and even tested) that it's possible to do a-arm bushing replacement
without the unloader tool, I have come to the conclusion that you really need it for the
1-ton install. I've had to load and unload the porkchops numerous times while dealing
with issues. Also, when replacing major components, it's likely the old ride height settings
won't be correct anyway so you'll at least need the tool to fix that.
Ideally, someone selling a 1-ton kit should have an unloader tool loaner program.
Ie, return the old a-arms and the unloader (in good condition) to get your deposit back.
thanks,
Karen
1973 23'
1975 26'
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1975 26'
San Jose, CA
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| Re: [GMCnet] a-arm adjuster cam, initial settings? [message #131445 is a reply to message #130774] |
Wed, 22 June 2011 11:04 |
KB
Messages: 1262
Registered: September 2009
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Here's a sort of philosophical question (well, maybe):
If you're trying to do front-end work on a coach and you don't have a perfectly
level place to work, would you:
a) park the coach and block the rear suspension (assuming you'd checked ride height in a level place previously)
or
b) park the coach, level it using the rear suspension, and then block the rear suspension at that height.
I realize final measurements should be checked in a level paved place, but we don't
all have the luxury of such a place to do the work.
thanks,
Karen
1973 23'
1975 26'
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1975 26'
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