| [GMCnet] Hndling vs ride height [message #182990] |
Mon, 03 September 2012 10:20  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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Hi Jay,
Go to my web site, http://jerrywork.com and on the GMC page you can download a presentation on alignment I did at GMCWS at Casa de Fruita. That will give you a detailed answer to your questions. The short answer as to why your ride height is now low is that any time the coach is jacked up it takes quite a bit of driving (five or more mimes often) for the suspension to settle in to where it will normally be going down the road. As the front end drops you loose caster (which effects the tendency to wander) as well as camber (pull to one side) and toe (scrubbing of the tires going down the road). Lowering the rear reestablished caster but altered the drive line angle and the anti-dive geometry built into the front end. Get the ride height set correctly at front and rear using the factory frame notches and drive the coach several miles. Check again to make sure it stays there. Your alignment likely will be spot on. Jim H. and Jim K. both have one of my alignment kits so
Jim H. can check to make sure it is correct.
My suggestion to everyone who has front end work done by others is to drive your coach ten or so miles and take it back for them to recheck front ride height before you leave for good. It takes more than one bite at the apple to get it right most of the time.
Jerry
Jerry Work
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
541-592-5360
-----------------------
Message: 16
Date: Mon, 03 Sep 2012 09:13:44 -0500
From: Jay Rabe <jayrabe@hotmail.com>
Subject: [GMCnet] Handling vs. ride height
To: gmclist@temp.gmcnet.org
Message-ID: <2caca.5044bb17@gmc.mybirdfeeder.net>
Content-Type: text/plain; charset="ISO-8859-15"
Hi,
Recently got a complete front end and steering rebuild and quad bags installed by Kanomota & Co. Very happy with the work and communication links and response in aftermath, but here's the problem. Handling on trip home to Oregon was very poor, worse than before. JimK suggested I check the ride height, and indeed it is way off - front about 7/8" too low, though rears are about right. When I lowered the rears and ran in manual, handling miraculously improved, confirming JK's diagnosis.
Not practical for me to take it back to CA for JimK to fix it, so the plan for long term solution is for Jim Hupy to take a look at it around the end of September when he's done with Canada and another trip to CA, and in his exceptional and legendary customer service, JimK will make everything right if there was a problem in his install, but meanwhile I'm just looking for some answers.
1) How could front end be so low after a rebuild? Offset bushings were installed, alignment came in good with 4 deg caster.
2) What is it about the geometry of the front-back suspension that so destroys handling if the rear is too high in relation to the front?
Thanks for my continuing education,
:)
Jay Rabe
76 PB
Portland, OR
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] Hndling vs ride height [message #182991 is a reply to message #182990] |
Mon, 03 September 2012 10:35  |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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Jerry:
I'm right in the middle of my alignment now.
Changing one thing changes others.
"Multiple bites at the apple".
Tweaking.
Turning the knobs.
Change it. Drive it. Adjust.
I could not believe how much of a difference a 30 minute mostly highway jaunt made with the coach.
Back at it. I'm out of adjustment room on the drivers side pork chop right now. I'm happy I have a torsion bar unloader. You can't do it without one.
Kudos on the alignment rig, Jerry. Your included suspension lesson is terrific.
Dolph Santorine
On Sep 3, 2012, at 11:20 AM, Work Jerry wrote:
> Hi Jay,
>
> Go to my web site, http://jerrywork.com and on the GMC page you can download a presentation on alignment I did at GMCWS at Casa de Fruita. That will give you a detailed answer to your questions. The short answer as to why your ride height is now low is that any time the coach is jacked up it takes quite a bit of driving (five or more mimes often) for the suspension to settle in to where it will normally be going down the road. As the front end drops you loose caster (which effects the tendency to wander) as well as camber (pull to one side) and toe (scrubbing of the tires going down the road). Lowering the rear reestablished caster but altered the drive line angle and the anti-dive geometry built into the front end. Get the ride height set correctly at front and rear using the factory frame notches and drive the coach several miles. Check again to make sure it stays there. Your alignment likely will be spot on. Jim H. and Jim K. both have one of my alignment kits s
o
> Jim H. can check to make sure it is correct.
>
> My suggestion to everyone who has front end work done by others is to drive your coach ten or so miles and take it back for them to recheck front ride height before you leave for good. It takes more than one bite at the apple to get it right most of the time.
>
> Jerry
> Jerry Work
> Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
> glwork@mac.com
> http://jerrywork.com
> 541-592-5360
> -----------------------
> Message: 16
> Date: Mon, 03 Sep 2012 09:13:44 -0500
> From: Jay Rabe <jayrabe@hotmail.com>
> Subject: [GMCnet] Handling vs. ride height
> To: gmclist@temp.gmcnet.org
> Message-ID: <2caca.5044bb17@gmc.mybirdfeeder.net>
> Content-Type: text/plain; charset="ISO-8859-15"
>
>
>
> Hi,
>
> Recently got a complete front end and steering rebuild and quad bags installed by Kanomota & Co. Very happy with the work and communication links and response in aftermath, but here's the problem. Handling on trip home to Oregon was very poor, worse than before. JimK suggested I check the ride height, and indeed it is way off - front about 7/8" too low, though rears are about right. When I lowered the rears and ran in manual, handling miraculously improved, confirming JK's diagnosis.
>
> Not practical for me to take it back to CA for JimK to fix it, so the plan for long term solution is for Jim Hupy to take a look at it around the end of September when he's done with Canada and another trip to CA, and in his exceptional and legendary customer service, JimK will make everything right if there was a problem in his install, but meanwhile I'm just looking for some answers.
>
> 1) How could front end be so low after a rebuild? Offset bushings were installed, alignment came in good with 4 deg caster.
>
> 2) What is it about the geometry of the front-back suspension that so destroys handling if the rear is too high in relation to the front?
>
> Thanks for my continuing education,
>
> :)
>
> Jay Rabe
> 76 PB
> Portland, OR
> -------------------------
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Hndling vs ride height [message #183000 is a reply to message #182991] |
Mon, 03 September 2012 12:41 |
Gary Berry
Messages: 1002
Registered: May 2005
Karma: -1
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Senior Member |
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Hey;
When I was at the last SOOR rally, Manny installed the 1-Ton
frontend for me (I was of little help). The next day, JerryW helped me
do the alignment with his GREAT alignment tools. I must have driven
over 100 miles that day just in 10 mile jaunts trying to get the ride
height set. All in all, a 6 hour exercise (but worth every minute). I
think if your ride height is off and you take it to someone (anyone)
to get it adjusted and it takes them less than a couple of hours, then
you're awfully lucky, or your ride height will be off after you drive
it down the road. Man, I LOVE that 1-Ton frontend...
--
Gary and Diana Berry
73 CL Stretch in Wa.
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