Just a Skosh or so. What would you do????

[Kent mosby]

1973 scamp. All new doctor diff front end rebuild last year. Qa1 k-member, manual steering, (converted from power). PST 1.03 t-bars, Viking shocks. Ride height 1 1/4 a-b measurement. This gives me almost 1/2 inch from bump stop.

I did a home alignment with an SPC Fastrax gauge. Right side is maxed out on rear upper control arm bolt. Left side maxed out as well. I did not adjust the front but they look maxed out as well.

My settings on the driver side 2.5* caster and 1 1/4 degree (-) camber
passenger side 1.5* caster and 1 degree (-) camber

Toe in is 3/16 inch.

There is a slight pull to the right. Would you reduce the caster and camber on the left? Would that help the pull that was not there before? FWIW, my driver side rear adjuster had slipped and was inward all the way. No adjustments made to the right side.

Before redoing the front end, the car was crabbing a bit and I installed 3 shims from Bergman to the left front leaf spring hanger. This helped a bit. Not sure the thrust of the rear is correct as I have never had an alignment at a shop.

I did speak to my tire store and spoke about a custom alignment and they said they would adjust to my specs. Of course they would be limited by hardware.

What to do??? Am I correct that if I reduce the camber, I lose caster as well?

 

[67Dart273]

With as "hot" as that car might be I would darn sure check the chassis alignment as a whole, AKA rear axle alignment. There are ways to do that at home. Personally I would accept closer to 0 camber for more caster. (Assume you run radials) I've been told even -1/2 degree is enough camber

If you try and set up to check axle alignment bear in mind that front and rear track is likely different widths, as well as wheel offset

On a side point, "Are you sure" the gauge is accurate?" I don't measure caster by a gauge, I measure camber, and figure caster from two readings, taken by turning the wheels in/ out. So far as camber, all that amounts to is in/ out tilt and you can at least check the gauge for zero on a plumb surface, and you can check THAT with a level. Rotate the level so the bubble is reversed, and any error should stay on the same end if the level is accurate, IE you put a level on a vertical column, and the bubble, say, "edges" to the post side. of the index mark on the bubble. If you turn the level around, and if it's accurate, the bubble should still be on the "post" side. If it goes outside, the level is "off."

 

[Kent mosby]

With as "hot" as that car might be I would darn sure check the chassis alignment as a whole, AKA rear axle alignment. There are ways to do that at home. Personally I would accept closer to 0 camber for more caster. (Assume you run radials) I've been told even -1/2 degree is enough camber

If you try and set up to check axle alignment bear in mind that front and rear track is likely different widths, as well as wheel offset

So, If I reduce the camber, I get more caster?? I did not know that. Yes, radials.

I did go through some chassis measurements and I think 3 shims may be too much. More like one or 2. I will determine that at the tire shop.

 

[67Dart273]

Think about how the A arms move. With the arms "all in" front and rear, you get maximum (negative) camber. But if you leave the rear pivot "all in" (inboard towards the engine) and lean the front one out a bit, this must tilt the (top of the) spindle outwards and reduce camber, but it also tilts the spindle BACK and increases caster

 

[Kent mosby]

Think about how the A arms move. With the arms "all in" front and rear, you get maximum (negative) camber. But if you leave the rear pivot "all in" (inboard towards the engine) and lean the front one out a bit, this must tilt the (top of the) spindle outwards and reduce camber, but it also tilts the spindle BACK and increases caster

That makes sense. Thanks

 

[72bluNblu]

-.5* camber is just fine for the majority of street cars. More can be beneficial for hard cornering or on a car that is frequently driven on winding roads, but it depends on the rest of the suspension and tire set up too. I run -1*, but I also run 275’s up front, and tires that wide change some things from an alignment perspective. Even then, if I had -1* camber and only +1.5* caster I would absolutely trade some of that camber for more caster. That’s not enough caster.

I generally set max caster first, so, front UCA adjuster set so it pushes the front UCA arm all the way “out”, rear adjuster set so it pulls the rear UCA arm all the way in.

3/16” is a lot of toe too, with a fresh rebuild you want more like 1/16”.

On a side point, "Are you sure" the gauge is accurate?" I don't measure caster by a gauge, I measure camber, and figure caster from two readings, taken by turning the wheels in/ out. So far as camber, all that amounts to is in/ out tilt and you can at least check the gauge for zero on a plumb surface, and you can check THAT with a level. Rotate the level so the bubble is reversed, and any error should stay on the same end if the level is accurate, IE you put a level on a vertical column, and the bubble, say, "edges" to the post side. of the index mark on the bubble. If you turn the level around, and if it's accurate, the bubble should still be on the "post" side. If it goes outside, the level is "off."

The Fastrax gauge calculates caster the same way. You’re just taking two camber measurements with the wheels turned and getting the caster reading from that. You just do it by adjusting the bubble level on the gauge.

The biggest thing with the Fastrax gauge is making sure you’ve got it attached to the wheel correctly and in a way that’s repeatable. The temptation is to hammer the height adjustment to make it stay put, but you can actually distort the frame of the gauge if you tighten it too much and that’ll mess with your readings. It takes some practice to get repeatable results.

 

[Kent mosby]

A bit of operator error on my first readings. I started the caster reading with the wheel straight and just moved the wheel in one direction. You need to start 15* in and move to 15 degrees out. OOPS

I then moved the UCA adjusters all the way to the inside on the rear and all the way to the outside on the fronts. Then I took it for a drive going around town, over RR tracks and turning tight circles at slow speed to settle things a bit.
Driver's side almost +4* caster and -1.5* camber
Passenger side +3.5* caster and -1* camber
Toe was 1/8 inch I left it there, I can finalize that after all is completed.

More caster than I expected. Next, I will get it to the alignment shop to double check everything and check the thrust angles that I cannot do as easily as caster and camber. Since I am maxed out on the front, would you compromise the caster to bring the camber down? I really don't want to raise the car up to reduce the camber if these settings are OK. I will double check my numbers at the alignment shop before any adjustments are made.

 

[Brooks James]

Moog offset uca bushing, more caster

 

[Kent mosby]

Moog offset uca bushing, more caster

I am ok with that caster but would you move the caster to 3* and hopefully get the camber to 0.5*? I am not sure if the movements would correlate to a 1 to 1 ratio. I would have to move the rear bolt out to reduce camber but that takes away caster as well. I don't want to change the bushings if I do not have to.

 

[72bluNblu]

Personally I wouldn’t want to go to less than +3* on the caster. That should get to under -1* on the camber, which should be fine for tire wear. You’re pretty much there on the passenger side. I’d just try to get the drivers side to match.