Front Wheel Alignment

[Dan Williams]

I have a 1972 Avanti II.  I have been told that my car has a Lark convertible frame and the front suspension is also the same as a Lark. I am trying to determine what the caster angle should be. The alignment shop report shows the caster angles as -2 degrees on both wheels.  From the Avanti Workshop Manual the caster angle should be = / - 3/4 degrees.

Any insight on this issue would be appreciated

Dan

Edited July 16, 2023 by Dan Williams
Corrected my name

[ronmanfredi]

Dan,  I'm working on a similar project and the caster on my recently purchased 82 model is -1.0 (L) , +.4 (R)  Camber is -.3 and -2.0.  It's obvious the right front wheel is tilted inward at the top (camber).  Most of the bushings are rotted, so I'm going to replace all of them and make modifications once I check the alignment again.  I'm an X auto tech and have ordered some basic alignment components to use at home to do this.  (turn tables, 1 caster/camber gauge).

The Avanti uses Kingpin/Spindles instead of ball joints/spindle.  The Kingpins do have an eccentric Pin at the top of the Kingpin that allows about 1 degree of camber adjustment and around 1 degree of caster.  The Pin is threaded into the Upper Kingpin metal bushings, so the caster adjustment is obtained by screwing the pin back and forth in the 2 bushings.  But, because there aren't any ball joints, the Kingpin can't move much for caster change without binding.  To make adjustments, you remove the upper pin rear grease nipple and insert a 1/4" allen wrench into the pin. (There is a pinch bolt that clamps down on the pin which has to be loosened first)  The eccentric pin can then be rotated and screwed back and forth.  Each full turn covers the entire range of camber, and moves the pin forward or backward to change the caster.

The old Lark frame design was for 0 to negative caster for old bias ply tires and manual steering so you could turn the wheels.  Newer radials and power steering can easily handle more caster to reduce wandering as you drive.  With this in mind, I'm going to replace the lower/upper arm bushings and replace the king pin to arm metal bushings if needed.  Once done, I'll do an alignment check and see what final adjustments I can make.  Next, I plan on tilting the Kingpins back at the top (to increase + caster).  This can be done by shimming the rear mount of the lower control arm at the crossmember mounting point and the front mount of the upper control arm.  This will tilt the king pin backwards at the top for more positive caster.  I'm guessing that 1/4" spacers is around 1-1 1/4 degree + caster.  If true, the I can fine tune the caster with the upper pins.  More than likely, the upper arm mounting bolts may need a little slotting for the bolts to go through once the lower arm is in place with the shim.  

Next is the Camber.  Once I know the final measurements after the caster is set to my liking, then I'll know if I'm going to have to slot the right side frame some to get the upper control arm out at the top (to increase camber).  If so, then I'll add a flat washer between the upper arm and frame on each end and tack weld it into place once everything is set.  This will prevent any slippage in the future.

Lastly will be to set the Toe in to 1/8-1/4" in.

Hope this helps.

 

 

[Dan Williams]

Thank you.  However, I think my front suspension looks different than the diagram you included.  Is it possible that they changed between 1972 and 1982?

Edited July 19, 2023 by Dan Williams

[ronmanfredi]

The diagram is not an Avanti,  it is just a basic front end with kingpins that I found so I could show you the location of the eccentric pin and king pin.  You can purchase a parts catalog and service manual from AvantiParts.biz or myersstudebakerparts.com for detailed images and rebuild/alignment instructions.

 

[Dan Williams]

Thank you.  I have the parts manual and service manual.  You answered my concerns.  🙂

[mfg]

As most know, the two Avanti upper control arm's inner shaft holes are factory drilled off center...The shaft can be flipped over to gain (or lose) about one degree of camber....Probably worth a try before you start slotting the frame holes.

Edited July 21, 2023 by mfg
added text

[Dan Williams]

Thank you

[ronmanfredi]

8 hours ago, mfg said:

As most know, the two Avanti upper control arm's inner shaft holes are factory drilled off center...The shaft can be flipped over to gain (or lose) about one degree of camber....Probably worth a try before you start slotting the frame holes.

On my 82 model, the offset holes are already positioned for maximum + Camber.

 

[mfg]

1 hour ago, ronmanfredi said:

On my 82 model, the offset holes are already positioned for maximum + Camber.

 

A bit unusual...

Your upper & lower control arm bushings are all in good shape..could there have been earlier accident damage on this Avanti?... Bent suspension part?

 

 

[ronmanfredi]

I'll be replacing the OEM bushings and then see where I am.  The car is all original, no accidents and the suspension/frame don't show any damage.  We will see when I get everything done.

 

[ronmanfredi]

On 7/21/2023 at 7:35 PM, mfg said:

A bit unusual...

Your upper & lower control arm bushings are all in good shape..could there have been earlier accident damage on this Avanti?... Bent suspension part?

 

 

Suspension is now off the car.  The Kingpin on the negative camber side is completely shot.  There wasn't any new grease inside because the grease fitting is stuck shut.  Needle bearings are solid rust, pin is worn badly in both locations.  

 

[Dan Williams]

 

 

Specifically which parts are you going to have to replace.  I have not taken my 72 to the alignment shop yet but i would like to have all the parts available in case I have the same problem.

[Gunslinger]

The last I had need to check…Studebaker International sells a complete king pin rebuild kit. The only thing not included is the labor involved to do it.  I believe Studebaker International will want the old, rebuildable parts back so they can be put back in the food chain, so to speak.

[mfg]

16 hours ago, ronmanfredi said:

Suspension is now off the car.  The Kingpin on the negative camber side is completely shot.  There wasn't any new grease inside because the grease fitting is stuck shut.  Needle bearings are solid rust, pin is worn badly in both locations.  

 

That's too bad....Very typical of how many Studebaker owners treated their front suspension parts back in the day when these cars were in regular service....A few shots of grease for the front suspension parts, on a regular basis, would have made the Stude/Avanti front end suspension almost bullet proof.

 

 

 

[ronmanfredi]

On 8/1/2023 at 4:10 PM, Dan Williams said:

 

 

Specifically which parts are you going to have to replace.  I have not taken my 72 to the alignment shop yet but i would like to have all the parts available in case I have the same problem.

On mine, I am replacing the upper and lower control arm bushings, King Pins with bearings/bushings/shims, Upper A Arm bumpers, Front Shocks and all related bolts/nuts/washers.  The King pins are remanufactured and require a core charge which is refunded once my old pins are returned.

[Dan Williams]

1 minute ago, ronmanfredi said:

On mine, I am replacing the upper and lower control arm bushings, King Pins with bearings/bushings/shims, Upper A Arm bumpers, Front Shocks and all related bolts/nuts/washers.  The King pins are remanufactured and require a core charge which is refunded once my old pins are returned.

 

2 minutes ago, ronmanfredi said:

On mine, I am replacing the upper and lower control arm bushings, King Pins with bearings/bushings/shims, Upper A Arm bumpers, Front Shocks and all related bolts/nuts/washers.  The King pins are remanufactured and require a core charge which is refunded once my old pins are returned.

Thanks