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Paul Keller
Champion Member
2 Posts |
 Posted - 06/13/2009 : 4:24:29 PM
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Thanks to the forum for all the past info and help.
Am
now completing (hopefully) a retro to R&P on a '63 Hawk using
forum/avnti info sites, bulking up the brackets and changing (several
times) the location of the rack. Want to increase caster to POSITIVE 2
1/2 - 3 1/2 degrees (No, do not want to go the Fatman/Must !! route).
Has anyone been able to exceed the 1 - 1 1/2 deg positive that is
available normally?? Any ideas as to mod'g the caster adjustment?? Any
leads at all??
Thanks again, Paul K, Oceano, CA |
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nels
Regal Member
420 Posts |
Posted - 06/13/2009 : 7:42:58 PM
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nels
Regal Member
420 Posts |
Posted - 06/13/2009 : 8:19:29 PM
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I did a lot of playing around using a 60 Lark about ten years ago. I
heated and twisted the lower knuckle, reversed the kp and other crazy
things. When I finally got what I wanted, about 3 degrees pos caster, I
decided the best approach would have been to move the upper ctrl arm
back by redrilling the holes and welding a new plate to match the
holes. This plate could be elevated in the front and welded or just
shimmed as necessary. The lower ctrl arm will need to be shimmed at the
rear or better yet, a plate of the apprpriate thickness welded between
the frame and the lower ctrl arm pivot. I think this plate needs to be
pretty thick to get three degrees. I really do think this is the best
way to go. |
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buddymander
Commander Member
1307 Posts |
Posted - 06/13/2009 : 8:31:34 PM
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| I elongated the upper front hole towards the outside about 3/32" |
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BobPalma
Commander Member
USA
4766 Posts |
Posted - 06/13/2009 : 9:07:22 PM
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I can't believe I'm reading this inquiry right now! What a conicidence
I saw this thread after Cari and I just returned from visiting Tom
& Judy Lawlis in Plainfield IN.
(It was overcast and
had rained hard late this afternoon, so we left the convertibles home
and took the 1964 Daytona sedan. We picked up Tom & Judy and
cruised the motel parking lots around the GoodGuys Hot Rod Show site,
checking out the cars.)
Anyway, as many of you know, Tom
Lawlis is SDC's 1957 Golden Hawk 400 guru. He is carefully restoring
the solid-color, Inca Gold 1957 "400" his brother bought off a gas
station corner on the west side of Indianapolis in 1960. It's been well-used in the family ever since, racking up about 199,000 miles in all kinds of midwest weather  before being set aside for restoration maybe 20 years ago.
Tom
acquired a 1957 Golden Hawk western frame and chassis from to build up
for the project. That bare frame is now on jack stands in Tom's shop,
having just been dismantled.
Tom was surprised at what he had
found where the lower control arm shaft attached at the front, at the
bottom of the large front crossmember. What he found and showed me (and
asked about) were three shims that
looked made for that very application, that had been sandwiched between
the bottom of the crossmember and the control arm shaft bracket "feet"
at the front end of the shaft.
Such shim placement would
certainly change caster, yet it was the first time in our lives either
of us (ages 63 and 66) had ever such shims. As I said, they looked made
for the application, with the two slots at 90-degree angles to one
another.
The slot positions would permit the technician to
loosen (but not remove) the bolts holding the front of the shaft to the
crossmember, pry the shaft down, and insert one end of the shim(s). He
would then rotate it (them, if more than one shim) around and under the
other of the two bolts.
Finally, the tech would tighten the bolts. The end result would be the lower control arm being positioned ever so slightly down at the front, changing the car's caster a few degrees by moving the lower end of the kingpin rearward ever so slightly.
So to answer your question, Paul: Yes, it can and apparently has been done, as I just saw first hand for the first time a couple hours ago on a 1957 Golden Hawk chassis being torn down.  BP
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nels
Regal Member
420 Posts |
Posted - 06/13/2009 : 9:14:22 PM
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It sounds as if they were shimming to get neg caster. I wonder why? The
factory R3 Avantis spec'd out more pos caster and this was accomplished
with shim at the rear of the lower ctrl arm shaft. |
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buddymander
Commander Member
1307 Posts |
Posted - 06/13/2009 : 9:32:46 PM
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| I've heard of shimming the rear lower arm to compensate for the elongated upper front hole. |
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BobPalma
Commander Member
USA
4766 Posts |
Posted - 06/13/2009 : 9:35:15 PM
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quote:
Originally posted by nels
It
sounds as if they were shimming to get neg caster. I wonder why? The
factory R3 Avantis spec'd out more pos caster and this was accomplished
with shim at the rear of the lower ctrl arm shaft.
It was easy to see why this had been done to this old chassis, Nels.
The bushings at the outer end of that lower control arm were hopelessly worn out. They were so worn they had ground out and cracked the large front hole at the outer end, ruining the lower conrol arm entirely.
Someone
had just shimmed it as described to bring it into alignment and
compensate for a worn part that should have been replaced. BP |
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hotwheels63r2
Commander Member
1832 Posts |
Posted - 06/13/2009 : 11:31:15 PM
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Flip the upper shafts over. (eccentricly drilled hole) Other wise, shim
the lowers. Be SURE your springs are possitioned as per the book, and
jounce the suspension to settle it. Never tighten the end caps until
the cars has actually driven.
MIKE |
Edited by - hotwheels63r2 on 06/13/2009 11:33:01 PM |
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cliffh
Champion Member
16 Posts |
Posted - 06/14/2009 : 12:26:16 AM
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A few years ago, I was disassembling a 55 K parts car and found a
professionally made caster shim with the slotted holes exactly as
described in the post above under the rear of the driver's side lower
inner pin. It was about 3/16" thick and was stamped with the numeral 1
and a degree symbol. Recently, I was working on my 54 coupe and could
not get better than about negative 2 1/2 degrees caster so I made a
couple of identical copies of this shim and installed them under the
rear of the lower inner pins. I did gain about 3/4 degree of caster.
Cliff
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Warren Webb
Golden Hawk Member
USA
660 Posts |
Posted - 06/14/2009 : 12:39:55 AM
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How about an angle iron bracket for the upper control arm mount? Drill
the bracket to accept the stock bolts to the frame & have the side
of the bracket drilled with longer bolts so as to accept shims & an
alignment proceedure similar to the period GM cars. The Stude alignment
using the hex in the upper outer pivot could still be used to fine tune
it.
60 Lark convertible
61 Champ
62 Daytona convertible
63 G.T. R-2,4 speed
63 Avanti (2)
66 Daytona Sport Sedan |
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leyrret
Golden Hawk Member
USA
538 Posts |
Posted - 06/14/2009 : 05:47:42 AM
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"It was about 3/16" thick and was stamped with the numeral 1 and a
degree symbol." That was caster or pinion axle shim available from
any
source that deals with alignment supplies.(i.e.heavy truck spring shop)
Placing a shim under one end only would place the ends of shaft on
different
mounting plane and side load bushing which may or may not shorten their
life(?).If you were to have one made long enough to fit under both ends
it would eliminate this concern. Same with upper shaft. Dropping rear
of lower and raising the front of upper equal amounts
would rotate the whole assembly and eliminate any binding of pins and bushing. |
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nels
Regal Member
420 Posts |
Posted - 06/14/2009 : 07:05:06 AM
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The axis of both upper and lower shafts and king pin upper and lower
axis must be parallel just as leyrret said. If you don't the upper and
lower will bind during suspension travel. When shim is added to the
front of the upper and back of the lower the upper must be moved back
accordingly to keep all four axis parallel. This gets the caster you
want. |
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showbizkid
Commander Member
USA
2592 Posts |
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BobPalma
Commander Member
USA
4766 Posts |
Posted - 06/14/2009 : 12:13:32 PM
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quote:
Originally posted by showbizkid
Bob, I wonder if Tom would allow someone to take photos and measurements of the shims he found so that they could be fabricated?
Clark in San Diego
I'm sure he would, Clark, and Tom is an excellent photographer. But he's not on the internet.
Having
held and inspected those shims last evening, they don't look so
terribly unique that they might not be available to alignment shops. I
will be at the tire & alignment shop where I trade on Tuesday as
I'll be there anyway for other business. I'll ask the owner to show me
an assortment of shims and see if something looks familiar.
From what Larryet said in a previous post, they may be over-the-counter items.
I have a note to check and will post back in a couple days. BP |
Edited by - BobPalma on 06/14/2009 7:56:43 PM |
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leyrret
Golden Hawk Member
USA
538 Posts |
Posted - 06/14/2009 : 5:19:08 PM
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Here's a couple pinion angle or caster shims. One is 4 degree and the
other an aluminum 1 degree. They come in various degrees, widths and
lengths. Some are slotted some just have a hole in them. The notches on
the 4 deg. I cut to clear u-bolts.
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buddymander
Commander Member
1307 Posts |
Posted - 06/14/2009 : 6:16:21 PM
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Flipping the upper shaft only changes camber. Also, let's not forget
about the stresses placed on the trunnions by the simple adjustment for
caster in a stock studebaker. Adjusting the trunnions twists the
kingpin angle thereby twisting the control arms as well. No matter what
you do, there will be strain on the trunnions unless you remount both
ends of both control arm shafts to set alignment. |
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buddymander
Commander Member
1307 Posts |
Posted - 06/14/2009 : 6:27:44 PM
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And while I'm on the subject, how many times have you disassembled a
trunnion to find the center shaft worn partially away because the inner
wasn't centered in the outer? I like my trunnion inners fully supported
by my trunnion outers...So; if you manage to crank your trunnions
enough to accomplish positive caster, better recheck the centering of
your inner. You'll find the inners riding on less outer and this will
cause premature wear of both. |
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cliffh
Champion Member
16 Posts |
Posted - 06/15/2009 : 9:23:09 PM
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Here is a picture and drawing of the caster shim I took off of a 55
hardtop. The second drawing is of the copies that I made. I didn't use
slotted holes because I thought it would be easier to take the bolts
all the way out while supporting the inner pin with a floor jack.
Cliff
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BobPalma
Commander Member
USA
4766 Posts |
Posted - 06/15/2009 : 9:38:50 PM
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Thanks for that post, Cliff. That's exactly the configuration of the
shim (three of them, actually) that was under the 1957 Golden Hawk
chassis Tom dismantled. Note that yours is stamped 1 degree; thinner
ones are stamped for less variation in caster. BP |
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Paul Keller
Champion Member
2 Posts |
Posted - 06/16/2009 : 4:32:15 PM
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Am VERY thankful for all the input - installation and drawings. This is better than the shop manual!!
Many thanks again, Paul K |
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leyrret
Golden Hawk Member
USA
538 Posts |
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PackardV8
Commander Member
USA
1386 Posts |
Posted - 06/16/2009 : 8:19:10 PM
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Am not sure those are wedges. They are a constant 3/16" thick, if I am reading the ad correctly.
thnx, jack vines
PackardV8 |
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leyrret
Golden Hawk Member
USA
538 Posts |
Posted - 06/17/2009 : 05:00:41 AM
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It states they are a constant thickness but it appears to be stamped
3/4 degree in the photo. This guy has several sizes listed . |
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PackardV8
Commander Member
USA
1386 Posts |
Posted - 06/17/2009 : 7:44:41 PM
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If they're a constant thickness, then the 3/4* could refer to camber, not caster.
thnx, jack vines
PackardV8 |
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leyrret
Golden Hawk Member
USA
538 Posts |
Posted - 06/18/2009 : 06:00:24 AM
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I don't see how a constant thickness shim could be marked for a fixed
degree because it would depend on the distance from pivot point, unless
the
shim is not universal and designed for a specific application. Either
way the markings are meaningless used as discussed here.
A 8 1/2" x
3" for the bottom and a 4 1/2" x 2" for the top of desired degree
should rotate your mounting surface to intended amount. Lots of people
custom make these as pinion angle shims for the 4 wheel drive crowd. If
made out of milder steel would be easy to drill the holes
so all you
would need is a solid shim without any holes or slots. This would be my
approach if I desired to change adjustment range to more
positive.
A bear frame could be bent up a few degrees but it could make body,
front sheet metal, and front bumper alignment a little more difficult.
This would involve removing a bottom section at the upward transition
point and flexing desired amount and then locking with
new bottom piece and bracing. A bit much for most people. |
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PackardV8
Commander Member
USA
1386 Posts |
Posted - 06/18/2009 : 10:18:52 AM
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Again, that listing is a CAMBER shim for cars which use those, it has
to be constant thickness. In that context, the degree stamp is correct.
Using
a pinion angle shim for Studebaker caster adjustment is a whole
different concept. The degrees stamped on the pinion shim probably have
very little correlation to the change in caster they would provide used
on a Stude front suspension.
thnx, jack vines
PackardV8 |
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leyrret
Golden Hawk Member
USA
538 Posts |
Posted - 06/18/2009 : 4:57:29 PM
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Camber shim is used generally to vary upper control pivot position.(in
and out) The extend a given thickness would vary the angle from
vertical would depend on the distance between the lower and upper pivot
points. Though they should be constant in thickness, unless designed for
a given distance between the two points the angle would vary and not be constant for a given shim thickness. |
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buddymander
Commander Member
1307 Posts |
Posted - 06/21/2009 : 12:54:02 AM
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There's no way you can keep the upper and lower control arms running
perfectly in the same arc and keep the arms from flexing and still
adjust for caster. Once you adjust the trunnions, you have tweaked the
spindle off center and stressed both control arms. That's why
Studebaker made them so flexible. They bend, they crack, and then they
break. It's the nature of the beast. |
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Topic |
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More Positive Caster
