Wandering steering/response/fishtailing

74_Coach

74_Coach

Active member
Oct 28, 2019
670
246
43
Central Coast, CA
Hi Everyone:

I just finished a complete front suspension rebuild including a steering box replacement but steering is still wonky wandering left, right, left,
right. I provided the GMC maintenance manuals for an explanation of the ride height adjustment and I know they got the height adjustment correct as
they wrote down all of the settings including front camber. But I am not sure the shop adjusted rear wheel camber - at all. I read this thread
http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=349032&rid=0&srch=Steering%20problems&SQ=7cb20fdc537ec765b800e80d2b03796b& that a
maladjusted camber on the tandem wheels can cause wandering. I have a tru-track that needs installed but not sure it will solve steering wander. And,
where would I find alignment shims for the rear if the camber was out of adjustment? I recall seeing an image in the GMC Service supplement that
showed shims for the rear alignment.

I posted this question on another unrelated thread and member Larry from WI responded with this valuable information:
Quote:
> Here is a post copy/pasted to this that I posted a while back. HTH
>
> Most of the time when someone complains of this kind of steering issue, the steering gear is no longer on "high point'. I'm guessing that at some
> time in the past, someone took your steering shaft apart and did not put it back together right. There is a very specific procedure that needs to be
> followed to get it back where it belongs. Alex Ferrara has mastered the art of putting it on high point and cured something over 100 GMC's with
> handling manners. So, driving your coach to Florida to have Alex F. do the adjustment on your steering box is not practical. So check out this set
> of instructions posted on the GMCphoto site of how to do high point.
>
> http://www.gmcmhphotos.com/photos/steering-gear-box/p52883-set-steering-box-highpoint.html
>
> Let us know how things turn out.

I am definitely heading back to the shop to see if they can check the steering box for correct center alignment. This shop has been in business for
over 45 years and my GMC is not the first one in their shop but probably not with my steering problems. Any suggestions would be appreciated.

Ed
--
Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of 6/26/19
 
The alignment specs in the book are correct as far as ride height is
concerned. But the camber, caster, and toe in/tow out are NO LONGER
CORRECT. Unless you are buying bias ply tires, which are not in common use
today.
Radial tires present a different footprint to the pavement static, as well
as dynamic. Correct specs should be, "0" degrees Camber, "3" degrees at
minimum, more (up to 5) is better. Toe is subject to discussion. But, front
drive vehicles tend to "drive around" their center axis, so start with +
1/32", and work towards Toe in. MOST GMC COACHES DO FINE WITH THESE
SETTINGS, but there are exceptions to the rule.
As far as the rear goes, wear is more important than specs. The rear
can, and often is responsible for what feels like, for all intents and
purposes, steering wander like you are complaining of. You feel slight
movement of the rear of the coach in your butt, "seat of the pants", and
compensate with slight steering inputs, thus the "right, left, right"
wiggle you are talking about. If the bogie pins and bushings are worn out,
(many, many are) no amount of fixing the front end of the coach is going to
cure that wander. Fix the rear, install your already purchased but not yet
installed stabilizers, and go on to other stuff.
Jim Hupy
Salem, Oregon

On Thu, Jan 2, 2020, 7:30 AM Ed Clerkin via Gmclist
wrote:

> Hi Everyone:
>
> I just finished a complete front suspension rebuild including a steering
> box replacement but steering is still wonky wandering left, right, left,
> right. I provided the GMC maintenance manuals for an explanation of the
> ride height adjustment and I know they got the height adjustment correct as
> they wrote down all of the settings including front camber. But I am not
> sure the shop adjusted rear wheel camber - at all. I read this thread
>
> http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=349032&rid=0&srch=Steering%20problems&SQ=7cb20fdc537ec765b800e80d2b03796b&
> that a
> maladjusted camber on the tandem wheels can cause wandering. I have a
> tru-track that needs installed but not sure it will solve steering wander.
> And,
> where would I find alignment shims for the rear if the camber was out of
> adjustment? I recall seeing an image in the GMC Service supplement that
> showed shims for the rear alignment.
>
> I posted this question on another unrelated thread and member Larry from
> WI responded with this valuable information:
> Quote:
> > Here is a post copy/pasted to this that I posted a while back. HTH
> >
> > Most of the time when someone complains of this kind of steering issue,
> the steering gear is no longer on "high point'. I'm guessing that at some
> > time in the past, someone took your steering shaft apart and did not put
> it back together right. There is a very specific procedure that needs to be
> > followed to get it back where it belongs. Alex Ferrara has mastered the
> art of putting it on high point and cured something over 100 GMC's with
> > handling manners. So, driving your coach to Florida to have Alex F. do
> the adjustment on your steering box is not practical. So check out this set
> > of instructions posted on the GMCphoto site of how to do high point.
> >
> >
> http://www.gmcmhphotos.com/photos/steering-gear-box/p52883-set-steering-box-highpoint.html
> >
> > Let us know how things turn out.
>
> I am definitely heading back to the shop to see if they can check the
> steering box for correct center alignment. This shop has been in business
> for
> over 45 years and my GMC is not the first one in their shop but probably
> not with my steering problems. Any suggestions would be appreciated.
>
> Ed
> --
> Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of
> 6/26/19
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
My bad. My cell phone changed the word Caster to camber. Correct specs are
0 Camber, +3 or more up to 5 CASTER, and +1/32" toe . Sorry.
Jim Hupy
Salem, Oregon

> The alignment specs in the book are correct as far as ride height is
> concerned. But the camber, caster, and toe in/tow out are NO LONGER
> CORRECT. Unless you are buying bias ply tires, which are not in common use
> today.
> Radial tires present a different footprint to the pavement static, as well
> as dynamic. Correct specs should be, "0" degrees Camber, "3" degrees at
> minimum, more (up to 5) is better. Toe is subject to discussion. But, front
> drive vehicles tend to "drive around" their center axis, so start with +
> 1/32", and work towards Toe in. MOST GMC COACHES DO FINE WITH THESE
> SETTINGS, but there are exceptions to the rule.
> As far as the rear goes, wear is more important than specs. The rear
> can, and often is responsible for what feels like, for all intents and
> purposes, steering wander like you are complaining of. You feel slight
> movement of the rear of the coach in your butt, "seat of the pants", and
> compensate with slight steering inputs, thus the "right, left, right"
> wiggle you are talking about. If the bogie pins and bushings are worn out,
> (many, many are) no amount of fixing the front end of the coach is going to
> cure that wander. Fix the rear, install your already purchased but not yet
> installed stabilizers, and go on to other stuff.
> Jim Hupy
> Salem, Oregon
>
> On Thu, Jan 2, 2020, 7:30 AM Ed Clerkin via Gmclist <

>
>> Hi Everyone:
>>
>> I just finished a complete front suspension rebuild including a steering
>> box replacement but steering is still wonky wandering left, right, left,
>> right. I provided the GMC maintenance manuals for an explanation of the
>> ride height adjustment and I know they got the height adjustment correct as
>> they wrote down all of the settings including front camber. But I am not
>> sure the shop adjusted rear wheel camber - at all. I read this thread
>>
>> http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=349032&rid=0&srch=Steering%20problems&SQ=7cb20fdc537ec765b800e80d2b03796b&
>> that a
>> maladjusted camber on the tandem wheels can cause wandering. I have a
>> tru-track that needs installed but not sure it will solve steering wander.
>> And,
>> where would I find alignment shims for the rear if the camber was out of
>> adjustment? I recall seeing an image in the GMC Service supplement that
>> showed shims for the rear alignment.
>>
>> I posted this question on another unrelated thread and member Larry from
>> WI responded with this valuable information:
>> Quote:
>> > Here is a post copy/pasted to this that I posted a while back. HTH
>> >
>> > Most of the time when someone complains of this kind of steering issue,
>> the steering gear is no longer on "high point'. I'm guessing that at some
>> > time in the past, someone took your steering shaft apart and did not
>> put it back together right. There is a very specific procedure that needs
>> to be
>> > followed to get it back where it belongs. Alex Ferrara has mastered the
>> art of putting it on high point and cured something over 100 GMC's with
>> > handling manners. So, driving your coach to Florida to have Alex F. do
>> the adjustment on your steering box is not practical. So check out this set
>> > of instructions posted on the GMCphoto site of how to do high point.
>> >
>> >
>> http://www.gmcmhphotos.com/photos/steering-gear-box/p52883-set-steering-box-highpoint.html
>> >
>> > Let us know how things turn out.
>>
>> I am definitely heading back to the shop to see if they can check the
>> steering box for correct center alignment. This shop has been in business
>> for
>> over 45 years and my GMC is not the first one in their shop but probably
>> not with my steering problems. Any suggestions would be appreciated.
>>
>> Ed
>> --
>> Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of
>> 6/26/19
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
 
Thank you Jim for the camber/caster specs. Yeah, bias-ply Tire's are now a relic and certainly radials change the specs. I need to break in the front
end first with ~300 miles before heading back to the shop. Front end is sitting high at the moment because of new/tight parts. But just driving this
beast is a challenge even below 45mph.
--
Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of 6/26/19
 
Make sure that your tires are not overinflated for the weight you are
carrying. Inflation information on tires is maximum pressure allowed under
maximum loading.
Jim Hupy
Salem, Oregon

On Thu, Jan 2, 2020, 8:35 AM Ed Clerkin via Gmclist
wrote:

> Thank you Jim for the camber/caster specs. Yeah, bias-ply Tire's are now a
> relic and certainly radials change the specs. I need to break in the front
> end first with ~300 miles before heading back to the shop. Front end is
> sitting high at the moment because of new/tight parts. But just driving this
> beast is a challenge even below 45mph.
> --
> Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of
> 6/26/19
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
One thing more, when setting the ride heights you MUST drive the coach
several miles to settle the coach and then take your ride height
measurements. If you require several adjustments, then you MUST drive and
resettle the coach. Failure to do so will cause the ride height to wander
all over the place, and you will be chasing your tail. This is wether you
do just the front or rear or both!

Some articles if you haven't reviewed are here:

http://www.gmceast.com/technical/Mueller_Steering_Inspection_Guide.pdf

http://www.gmceast.com/technical/Wirth_GMCMH_Steering_Box.pdf

Dave Lenzi provides a procedure on how to center the steering wheel with
his steering boxes and is the correct way to center the steering wheel. I
have a copy at home but NOT with me here in Tucson. If any one has bought
a Lenzi steering box and has the procedure then it would be helpful to post
it. Dave is NOT available at this time.

Other helpful information is listed here:

http://bdub.net/gmcmotorhome.info/steering.htm

The GMC motorhome can be a dream to drive when it is setup right and it in
not a one adjustment or componet part that fixes all, but a number of
measurements that result in the final ride.

J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)

On Thu, Jan 2, 2020 at 9:49 AM James Hupy via Gmclist <

> Make sure that your tires are not overinflated for the weight you are
> carrying. Inflation information on tires is maximum pressure allowed under
> maximum loading.
> Jim Hupy
> Salem, Oregon
>
> On Thu, Jan 2, 2020, 8:35 AM Ed Clerkin via Gmclist <
> gmclist>

>
> > Thank you Jim for the camber/caster specs. Yeah, bias-ply Tire's are now
> a
> > relic and certainly radials change the specs. I need to break in the
> front
> > end first with ~300 miles before heading back to the shop. Front end is
> > sitting high at the moment because of new/tight parts. But just driving
> this
> > beast is a challenge even below 45mph.
> > --
> > Ed Clerkin | 1974 GMC Canyon Lands 26’ | 14,445 original miles as of
> > 6/26/19
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Good Luck. unfortunately if you search, this is way too common of a problem. the "just rebuilt my front end and now it wanders" is all too
common of a problem. It all comes down to the entire system at that point. I have seen idler arms installed backward, wrong bushings used. All
sorts of crazy things done by "professional". Also always check the lower ball joint, and those bolts come loose way too often after a front end
rebuild. There also is some "wrong" idler arms out there.

Start with checking and verifying everything and do not take any mechanic's word for it, verify it yourself.

Like stated above too- you have to drive it between adjustments of not only ride height, but also alignment changes.
--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
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