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Paul Keller
Champion Member

2 Posts

Posted - 06/13/2009 :  4:24:29 PM  Show Profile  Email Poster  Reply with Quote
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

nels
Regal Member

420 Posts

Posted - 06/13/2009 :  7:42:58 PM  Show Profile  Email Poster  Reply with Quote
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nels
Regal Member

420 Posts

Posted - 06/13/2009 :  8:19:29 PM  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
"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  Show Profile  Email Poster  Reply with Quote
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

Posted - 06/14/2009 :  10:42:19 AM  Show Profile  Email Poster  Visit showbizkid's Homepage  Reply with Quote
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
'63 F2/Lark Standard
https://studeblogger.blogspot.com
www.studebakersandiego.com
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BobPalma
Commander Member

USA
4766 Posts

Posted - 06/14/2009 :  12:13:32 PM  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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

Posted - 06/16/2009 :  6:03:39 PM  Show Profile  Email Poster  Reply with Quote
This looks very much like whats pictured.https://cgi.ebay.com/ebaymotors/Universal-10-Caster-Camber-3-16-Thick-Shims_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116QQhashZitem1bf5b4c457QQitemZ120086381655QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
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PackardV8
Commander Member

USA
1386 Posts

Posted - 06/16/2009 :  8:19:10 PM  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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  Show Profile  Email Poster  Reply with Quote
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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