Increased Caster

K

Ken H.

Active member
Sep 9, 2000
19,428
5
38
Time for a survey of those using Dave Lenzi's upper A-arms modified for
increased caster:

What's your opinion after using them for a while? Do they significantly
increase the steering stability? Did you try the offset bushings before
going to modified A-arms? How do they compare? Did either affect the
steering effort significantly? Which is the "better buy" -- or is either
worth the trouble/cost?

Thanks for your opinions.

Ken H.
 
This is a project that is on my "want" list, but I do not want to do the labor yet, so not sure if it will happen sometime in the near future. I am
thinking for sure steering box this year, since I have one, and the electric wiper kit. I also want to put a beefier track bar in. After that it is
time to look at bushings and adding that caster.

There are GMC owners that really like the offset bushings. I have heard real good things about Dave's arms, however I am under the impression that
they are no longer available. Maybe you have some? There is a GMC that has a bad frame and engine here in MN that has a set of Dave's arms on it,
and someone was discussing buying that coach just for the Arms because he mentioned Dave no longer does the arms.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
Last word I heard was that Dave is willing to do TWO pair, but would rather
not fool with just one pair -- probably has to do with the labor of setting
up the jigs, I'd guess. I know of one person who's probably ready. Maybe
if someone else chimes in, they can get together and strike a deal with
Dave -- or more might be better.

Ken H.

On Thu, Jan 14, 2021 at 3:25 PM Jon Roche via Gmclist <

> This is a project that is on my "want" list, but I do not want to do the
> labor yet, so not sure if it will happen sometime in the near future. I am
> thinking for sure steering box this year, since I have one, and the
> electric wiper kit. I also want to put a beefier track bar in. After that
> it is
> time to look at bushings and adding that caster.
>
>
>
>
> There are GMC owners that really like the offset bushings. I have heard
> real good things about Dave's arms, however I am under the impression that
> they are no longer available. Maybe you have some? There is a GMC that
> has a bad frame and engine here in MN that has a set of Dave's arms on it,
> and someone was discussing buying that coach just for the Arms because he
> mentioned Dave no longer does the arms.
>
>
>
> --
> Jon Roche
> 75 palm beach
> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
I have installed offset bushings on stock front ends as part of a repair of
the entire front end, and also in 1 ton conversions. They are nearly always
capable of allowing 5° of camber. That is probably the maximum that you
need. Any more, and the steering box will groan in protest. If you feel
that you need more than that to make your coach go "hands off" straight
down the road, look elsewhere for your problem. Worn bogie pins and
bushings will give your coach a bad case of the "wig wags" as will bent
bogie arms. This will be felt in the seat of your pants, and is often
followed by minor corrections with your hands on the steering wheel. Then
the assumption will be made that the problem lies with the front end parts.
So, do not forget the rear wheels when chasing steering problems.
As for Dave's control arms, I have no experience with them.
Jim Hupy
Salem, Oregon

On Thu, Jan 14, 2021, 12:44 PM Ken Henderson via Gmclist <

> Last word I heard was that Dave is willing to do TWO pair, but would rather
> not fool with just one pair -- probably has to do with the labor of setting
> up the jigs, I'd guess. I know of one person who's probably ready. Maybe
> if someone else chimes in, they can get together and strike a deal with
> Dave -- or more might be better.
>
> Ken H.
>
> On Thu, Jan 14, 2021 at 3:25 PM Jon Roche via Gmclist <

>
> > This is a project that is on my "want" list, but I do not want to do the
> > labor yet, so not sure if it will happen sometime in the near future.
> I am
> > thinking for sure steering box this year, since I have one, and the
> > electric wiper kit. I also want to put a beefier track bar in. After
> that
> > it is
> > time to look at bushings and adding that caster.
> >
> >
> >
> >
> > There are GMC owners that really like the offset bushings. I have
> heard
> > real good things about Dave's arms, however I am under the impression
> that
> > they are no longer available. Maybe you have some? There is a GMC
> that
> > has a bad frame and engine here in MN that has a set of Dave's arms on
> it,
> > and someone was discussing buying that coach just for the Arms because he
> > mentioned Dave no longer does the arms.
> >
> >
> >
> > --
> > Jon Roche
> > 75 palm beach
> > EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
> > St. Cloud, MN
> > http://lqqkatjon.blogspot.com/
> >
> > _______________________________________________
> > 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
>
 
I did my front end back in 2007 or so, before Dave was doing the upper arms. So after confiring with Steve Ferguson, who was the expert at the time,
I installed the offset bushings. Had access through a GMC friend to the GM tools to do the job. When I do check my alignment, I now can get 4* on one
side and 3.5* caster on the other. Between that and setting the steering box on high point, steering is one handed. (though I mostly have two on the
wheel...just because I should...) Installing offset bushings is a time consuming job, but IMO because of the difference in cost, worth the effort to
try it. After doing it, I did notice a positive difference in handling. But that may have been cumulative of all of the other stuff I did at the time.
JMHO
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
FWIW I got about 4 deg on a 77 with no offset bushings. Of course one side was limiting factor and I stopped where camber would start to go negative.
If I could find the scrap of cardboard I was using as a note sheet in the process I could give exact numbers, but was several years ago. Numbers
don’t lie as equal caster gave a road test with no pull hands off wheel first try.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I hate you all. With offset upper bushings we had to work to get zero caster
________________________________
From: Gmclist on behalf of John R. Lebetski via Gmclist
Sent: Thursday, January 14, 2021 5:00 PM
To: gmclist
Cc: John R. Lebetski
Subject: Re: [GMCnet] Increased Caster

FWIW I got about 4 deg on a 77 with no offset bushings. Of course one side was limiting factor and I stopped where camber would start to go negative.
If I could find the scrap of cardboard I was using as a note sheet in the process I could give exact numbers, but was several years ago. Numbers
don’t lie as equal caster gave a road test with no pull hands off wheel first try.
--
John Lebetski
Woodstock, IL
77 Eleganza II

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> I hate you all. With offset upper bushings we had to work to get zero caster

Hummm. Never heard of this...... Is it possible that you put the bushings in wrong?
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
Sir, or possibly got caster and camber mixed up?

> > I hate you all. With offset upper bushings we had to work to get zero caster
>
> Hummm. Never heard of this...... Is it possible that you put the bushings in wrong?

--
C. Boyd
76 Crestmont
East Tennessee
 
We supply the offset bushing and encourage people to use it on the back arm
as using it on both does not gain.
We supply our own instructions.

On Thu, Jan 14, 2021 at 7:40 PM Charles Boyd via Gmclist <

> Sir, or possibly got caster and camber mixed up?
>
>
>
>
>

> > > I hate you all. With offset upper bushings we had to work to get zero
> caster
> >
> > Hummm. Never heard of this...... Is it possible that you put the
> bushings in wrong?
>
>
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
The increase in caster won't cure the bump steer in the one ton conversion.
--
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
 
Did you put them in the correct holes? ;)

Sully
Bellevue wa

On Thu, Jan 14, 2021 at 5:02 PM Keith V via Gmclist
wrote:

> I hate you all. With offset upper bushings we had to work to get zero
> caster
> ________________________________
> From: Gmclist on behalf of John R.
> Lebetski via Gmclist
> Sent: Thursday, January 14, 2021 5:00 PM
> To: gmclist
> Cc: John R. Lebetski
> Subject: Re: [GMCnet] Increased Caster
>
> FWIW I got about 4 deg on a 77 with no offset bushings. Of course one side
> was limiting factor and I stopped where camber would start to go negative.
> If I could find the scrap of cardboard I was using as a note sheet in the
> process I could give exact numbers, but was several years ago. Numbers
> don’t lie as equal caster gave a road test with no pull hands off wheel
> first try.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> 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
>
 
Doing the offset bushings or Daves control arms to get more caster is a good thing. But unless your steering gear is centered (AKA on "high point")
you may still have wandering issues. It all comes from the lower shaft between the upper steering shaft and the steering box. If that shaft has been
taken apart at sometime in the past, there is a good chance that it was put back together wrong. Dave Lenzi noted this some time ago and was picked up
by Alex Ferrara who was then responsible for correcting steering issues on several hundred coaches. So, while you are at it, doing the offset bushing
thing, see this set of pictures documented by Alex, and put your steering box on high point. JWID

http://www.gmcmhphotos.com/photos/steering-box/p54238-steering-box-adjustment.html

Also this by Rob

http://www.gmcmhphotos.com/photos/steering-gear-box/p52883-set-steering-box-highpoint.html
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
knowing me its highly likely. I'll check in the summer.
But my recollection is that the caster is better now than it was.

Also Yes caster not camber

________________________________
From: Gmclist on behalf of Larry via Gmclist
Sent: Thursday, January 14, 2021 9:11 PM
To: gmclist
Cc: Larry
Subject: Re: [GMCnet] Increased Caster

> I hate you all. With offset upper bushings we had to work to get zero caster

Hummm. Never heard of this...... Is it possible that you put the bushings in wrong?
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

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Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> knowing me its highly likely. I'll check in the summer.
> But my recollection is that the caster is better now than it was.
>
> Also Yes caster not camber
>
> ________________________________
> From: Gmclist on behalf of Larry via Gmclist
> Sent: Thursday, January 14, 2021 9:11 PM
> To: gmclist
> Cc: Larry
> Subject: Re: [GMCnet] Increased Caster
>

> > I hate you all. With offset upper bushings we had to work to get zero caster
>
> Hummm. Never heard of this...... Is it possible that you put the bushings in wrong?
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> 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

Keith, I almost put them in wrong. Spent a lot of time in email and phone calls with Steve Ferguson before I understood the geometry. That was 2005,
so CRS has taken over relative to the proper install of the offset bushings. Maybe someone who has done this recently or many times could speak up
here.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
If you put in the bushings, have the cams at max, and can only get zero, you put them in backwards. You want the rear of the upper arm to move
INBOARD. That moves the upper ball joint rearward.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
That would be great! I definitely will be checking after the snow melts.
I do understand steering geometry so I want to believe I did it right. But I'm also very good and making stupid mistakes
________________________________
From: Gmclist on behalf of John R. Lebetski via Gmclist
Sent: Wednesday, January 20, 2021 10:07 AM
To: gmclist
Cc: John R. Lebetski
Subject: Re: [GMCnet] Increased Caster

If you put in the bushings, have the cams at max, and can only get zero, you put them in backwards. You want the rear of the upper arm to move
INBOARD. That moves the upper ball joint rearward.
--
John Lebetski
Woodstock, IL
77 Eleganza II

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Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I've got another question (or more) for this survey:

1. Is it feasible to use offset bushings in both the rear AND front of the
upper A-arms? Seems to me it should be perfectly OK and potentially give
about twice as much caster increase as using them only in the rear.

2. Seems to me installing the offset bushing in the rear, to increase
caster, would inevitably tend to move camber toward negative. By the same
rationale, using offset bushings front and rear would have less effect on
camber because the front would tend toward positive camber about equal to
the rear's negative effect.

3. Has anyone considered or tried the offset upper A-arm shafts? Like
this:
bit.ly/3obunmp
or
https://www.globalwest.net/billet-steel-stock-upper-control-arm-offset-cross-shaft-camaro-67-68-69-global-west.html

I have no idea whether those are available to fit the GMC, but we've got
plenty of folks capable of designing and building them. It might be easier
than modifying A-arms, as Lenzi does. What are the pros & cons?

4. Other options?

Rest assured, I'm just trying to learn something here -- I'm happy with my
1-ton front end -- and it was installed before Manny decided to increase
the caster. (I THINK I did use offset bushings in the rear though -- tooo
long ago for my old memory to be sure.)

Thanks for all your inputs/ideas.

Ken H.

On Thu, Jan 14, 2021 at 11:42 AM Ken Henderson
wrote:

> Time for a survey of those using Dave Lenzi's upper A-arms modified for
> increased caster:
>
> What's your opinion after using them for a while? Do they significantly
> increase the steering stability? Did you try the offset bushings before
> going to modified A-arms? How do they compare? Did either affect the
> steering effort significantly? Which is the "better buy" -- or is either
> worth the trouble/cost?
>
> Thanks for your opinions.
>
> Ken H.
>
 
Well, I guess I've had my head screwed on backward for quite some time:
I've been thinking, and discussing, the use of offset bushings in the UPPER
REAR of the upper A-arm. Tonight, I've been researching offset bushing
part numbers. LO and BEHOLD: Moog (and everyone else) ONLY mentions
eccentric (offset) bushings for the upper FRONT! NOT the rear! Holy Moly,
why hasn't someone called me on that? Or have we GMCers been "doing our
own thing"?

Here are the ONLY Moog part numbers I've found for '76 Toronado (and by
extension GMCMH):

Standard Offset(Eccentric)
Upper Front K7006 K7104
Upper Rear K6111
Lower Front K5222
Lower Rear K6116

Does this mean that the K7104 will ONLY fit the Upper Front, or merely that
that's where they're recommended (but CAN fit the rear?).

Come on, somebody straighten this mess out.

Ken H.

On Wed, Jan 20, 2021 at 9:01 PM Ken Henderson
wrote:

> I've got another question (or more) for this survey:
>
> 1. Is it feasible to use offset bushings in both the rear AND front of
> the upper A-arms? Seems to me it should be perfectly OK and potentially
> give about twice as much caster increase as using them only in the rear.
>
> 2. Seems to me installing the offset bushing in the rear, to increase
> caster, would inevitably tend to move camber toward negative. By the same
> rationale, using offset bushings front and rear would have less effect on
> camber because the front would tend toward positive camber about equal to
> the rear's negative effect.
>
> 3. Has anyone considered or tried the offset upper A-arm shafts? Like
> this:
> bit.ly/3obunmp
> or
>
> https://www.globalwest.net/billet-steel-stock-upper-control-arm-offset-cross-shaft-camaro-67-68-69-global-west.html
>
> I have no idea whether those are available to fit the GMC, but we've got
> plenty of folks capable of designing and building them. It might be easier
> than modifying A-arms, as Lenzi does. What are the pros & cons?
>
> 4. Other options?
>
> Rest assured, I'm just trying to learn something here -- I'm happy with my
> 1-ton front end -- and it was installed before Manny decided to increase
> the caster. (I THINK I did use offset bushings in the rear though -- tooo
> long ago for my old memory to be sure.)
>
> Thanks for all your inputs/ideas.
>
> Ken H.
>
>
> On Thu, Jan 14, 2021 at 11:42 AM Ken Henderson

>
>> Time for a survey of those using Dave Lenzi's upper A-arms modified for
>> increased caster:
>>
>> What's your opinion after using them for a while? Do they significantly
>> increase the steering stability? Did you try the offset bushings before
>> going to modified A-arms? How do they compare? Did either affect the
>> steering effort significantly? Which is the "better buy" -- or is either
>> worth the trouble/cost?
>>
>> Thanks for your opinions.
>>
>> Ken H.
>>
>
 
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