Home » Public Forums » GMCnet » [GMCnet] GMC alignment kit and instructions now complete
| [GMCnet] GMC alignment kit and instructions now complete [message #141209] |
Sat, 27 August 2011 11:37  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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Hi all,
The GMC alignment kit is now complete and will be tested by a number of users at the upcoming unofficial southern Oregon non-rally (SOOR) in a couple of weeks. I published the 30 page illustrated guide on my web site (http://jerrywork.com) today. Go to the GMC Motorcoach page and click on "- Everything you need to know about aligning your GMC to run straight and true". The file posted is release version 0.5 beta. Once I get feedback from these SOOR users, and any comments/corrections you care to email to me, I will produce a final release 1.0. The file is in .pdf format. I left it about 8mb in size for best image quality and will likely reduce the file size for the official release version.
The guide is in several sections:
The first talks about why it is hard for most commercial alignment shops to properly align our GMC motorcoaches.
The second talks about the different components an owner needs to do their own alignment measurement and my objectives for this kit.
The third section is a detailed nine step process that takes about 30 minutes by which any GMC owner can do an accurate measurement of front and rear ride height, front camber, caster, toe and centering of the steering box, plus rear camber and frame parallelism on all four bogie wheels.
The forth section gives detailed instructions on how to build or acquire all the components for an alignment measurement kit like this one.
My hope is that through the largess of this forum group you will help each GMC club acquire this important safety kit and make it available to all GMC club members. You can use my guide to build a kit and donate to your GMC club, or help them acquire a kit from me if you prefer. I don't care how the clubs get the kit, I just want to make sure each club has a kit available. Our GMCs were noted for their fine and easy drive style when new, but many current owners experience a far less comfortable or safe driving coach. From what I have learned, I believe improper alignment of the front and rear may be the basic reason these coaches handle far less well than most. And, improper procedure by commercial alignment shops may well be the root cause issue.
The .pdf file you download contains copyrighted, restricted use material. You are free to use the information for any non-commercial purpose yourself, and may post the file or links to the file (wait for release 1.0) on any GMC club, vendor or member website, but you cannot use the materials for any commercial purpose without my expressed written consent to do so. Thanks. I look forward to your feedback.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
541-592-5360
Founder of the Southern Oregon Guild
www.southernoregonguild.org
Member of the Siskiyou Guild
www.siskiyouguild.org
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] GMC alignment kit and instructions now complete [message #141254 is a reply to message #141209] |
Sat, 27 August 2011 17:05  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Jerry,
Your alignment kit and procedure reflects a TREMENDOUS amount of attention to detail, a quality that in today's world is sadly
lacking!
As we say Downunder, Good on Yah, Mate!
Regards,
Rob M.
-----Original Message-----
From: Work Jerry
Hi all,
The GMC alignment kit is now complete and will be tested by a number of users at the upcoming unofficial southern Oregon non-rally
(SOOR) in a couple of weeks.
Jerry
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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] GMC alignment kit and instructions now complete [message #141259 is a reply to message #141209] |
Sat, 27 August 2011 17:27 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
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Senior Member |
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i have a question about centering the steering box. from other sources it is necessary to align the flat on the box shaft with a surface on the box casting. someone else said you could do as you have said i.e. turn lock to lock and split the difference to find center. i have not tried your method yet so i'm just asking.
BTY very nice presentation.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] GMC alignment kit and instructions now complete [message #141287 is a reply to message #141282] |
Sat, 27 August 2011 21:20 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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So, is yours the only RHD GMC Motorhome, or are there others?
Dolph
On Aug 27, 2011, at 9:17 PM, Rob Mueller wrote:
> Fred,
>
> Reference MM X-7525 / Page 9-38 Steering / Paragraph - Pitman Arm Shaft Over-Center Sector Adjustment / Step 2.
>
> Turn the stub shaft from stop to stop, counting the total number of turns. Divide this number by two. Starting at either stop, turn
> the stub shaft 1/2 the total number of turns. This is the "center" of the gear. The flat on the stub shaft is normally up and
> parallel with the side cover when the gear is "on center" (figure 64) and the block tooth on the pitman shaft is in line with the
> over-center preload adjuster (figure 65).
>
> The way this is written leads me to believe that counting the turns and turning half the number to find center is the CORRECT way to
> find center. The use of the word "normally" in the sentence above leads me to believe that the flat might not be aligned but the
> steering box would still be centered.
>
> Even though I've read this procedure many times and adjusted my steering box with Tom Hampton the statement; "the block tooth on the
> pitman shaft is in line with the over-center preload adjuster (figure 65)" is an indication that he steering box is "on center"
> hadn't registered in my grey matter until now.
>
> I paged through the steering section to try and find a photo of the pitman arm removed from the steering box that showed if the
> pitman arm had a block tooth and if it did where it was located but could not find one.
>
> I then checked the Parts Book 78Z Page 16-2 Figure 16.002 Linkage - Steering (Includes Component Parts) Key 9 - Arm - Pitman but
> could not tell from the line drawing if it had a block tooth.
>
> I went to the PhotoSite and did a search "Pitman" tried to find some photos of the pitman arm by itself but nothing popped up.
>
> However, I did a find this series of photos by J. Harper:
>
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=10779
>
> It appears to me that the centerline of the pitman arm aligns with the block tooth on the steering box. Therefore if there is a
> matching block tooth machined into the Pitman arm at it's centerline it could used to confirm that the steering box was on center as
> per figure 65 of the MM as referenced above.
>
> Unfortunately in the picture below it appears that there is another block tooth eight teeth to the left of the one marked in red!
>
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=11149
>
> I cannot answer the following questions myself as The Blue Streak was converted to RHD using a 1959 Cadillac steering box.
>
> 1) Does anyone have an OEM Pitman arm that is not attached to a steering box to determine if it has a block tooth and if yes where
> it is located in the splined section?
>
> 2) Does anyone have an OEM Steering box to confirm that there is more than one block tooth on the pitman arm spline?
>
> Regards,
> Rob M.
>
>
> -----Original Message-----
> From: fred veenschoten
>
> i have a question about centering the steering box. from other sources it is necessary to align the flat on the box shaft with a
> surface on the box casting. someone else said you could do as you have said i.e. turn lock to lock and split the difference to find
> center. i have not tried your method yet so i'm just asking.
>
> BTY very nice presentation.
>
> Fred
>
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| Re: [GMCnet] GMC alignment kit and instructions now complete [message #141294 is a reply to message #141292] |
Sat, 27 August 2011 22:38 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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G'day,
John is correct, however, mine is the only one that was converted using a Caddy steering box. All the others I know of used the OEM
GMC steering box.
Regards,
Rob M.
-----Original Message-----
From: John Sharpe
Rob, Peter Bailey, Mark Bennett and others have coaches that have been converted to RHD.
--
John
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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] GMC alignment kit and instructions now complete [message #141338 is a reply to message #141209] |
Sun, 28 August 2011 10:44 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Quote: 2 since it does not seem to matter if caster is different on right or
left, and since the rotation plates are only to measure caster, we
should not need the plates if we just adjust for max.
I thought it totally matters that the caster was the same on both sides as that is what controls whether you will pull to one side.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] GMC alignment kit and instructions now complete [message #141395 is a reply to message #141332] |
Sun, 28 August 2011 17:58 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Gene,
1 - should read "since those of us that don't have a set of Dave Lenzi's offset upper control arms can only get 3 deg of Caster."
;-)
2 - "Somewhere" I read that caster should be set the same on both sides unfortunately for the life of me I can't remember where.
Also when I looked at the report I got on the alignment from the shop in Houston there were three groups: Left / Right / Cross.
Cross was the difference Left to Right.
All the spec's I've read on alignment give you a ± for each setting including caster.
Regards,
Rob M.
-----Original Message-----
From: gene Fisher
wow nice job, it is super to have someone working this problem for us
http://thedovetailjoint.squarespace.com/storage/GMC%20alignment.pdf
brings up my age old questions (now someone can test these)
1 since we can only get 3 deg. of Caster even if we use off-set,
inserts , why do we even bother to measure caster? Just adjust for
the max. (on standard systems or the 1 Ton VII)
2 since it does not seem to matter if caster is different on right or
left, and since the rotation plates are only to measure caster, we
should not need the plates if we just adjust for max.
just asking
gene
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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] GMC alignment kit and instructions now complete [message #141528 is a reply to message #141209] |
Mon, 29 August 2011 11:46 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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| glwgmc wrote on Sat, 27 August 2011 09:37 |
... The GMC alignment kit is now complete and will be tested by a number of users...
... Once I get feedback from these SOOR users, and any comments/corrections you care to email to me, I will produce a final release 1.0. ...
|
Jerry,
I have finally had a chance to look at it.... excellent work. (But you always do good work. So we shouldn't be surprised.)
But one typo jumped out and smacked me...
On the bottom of page 3: "At the rear we need to make sure all four bogie wheels are running parallel with the frame and that all have about one degree of negative caster when the coach is settled in at proper ride height."
Shouldn't that be "one degree of negative camber" ???
Just a typo that isn't really in the instruction part of the document. But it did smack me.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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