Caster is off...how should I fix it?

[Tywebb2]

Next up this winter is to get the front end straightened out on my '72 Cuda.  I had it aligned last year and everything checked out except for the caster.  They could only get a max of 0.8 on the right and -2.1 on the left.  The car was restored about 3 years ago and all front bushings were replaced along with a set of new heavy duty front strut rods.  I did have to install an Auto Rust Technicians front left frame rail cap because it had rusted out in the typical spot from battery acid.  My guess is that is slightly off and causing my caster to be out on the left side?

Anyway...what would be the best (and cheapest) way to correct the difference and get both sides to around +2-3deg?  As it drives now I am being pulled into oncoming traffic and the car isn't real stable at high speeds (at the end of the track when slowing down).

   1.  shave the front strut rod bushing down on the left side so that it pulls the LCA forward to even the sides out...then install offset upper control arm bushings?
   2.  machine and thread the strut rod so that a nut can be place both front and back making it adjustable...then installing offset upper control arm bushings?
   3.  installing adjustable strut rods and offset upper control arm bushings?
   4.  installing adjustable upper control arms?

I was planning on doing #4 but if I can get away with fixing it some other way while saving money and still keeping things safe I would be open to it. 

[vitamindart]

if they adjust the caster so there isn't so much of a difference it will stop pulling ,1.3 cross caster is too much!! my suggestion would be adjustable uppers at least if you want it to spec. i have bills (RMS) tubular uppers and his strut rods and my car has never aligned easier
it use to have a simalar problem as yours i tried messing with the strut rods to fix it and ended up with binding in the lower control arms

[Tywebb2]

Those caster #'s are with both sides max'd out.  So if I back off on the right side that would leave me with -2.1 on both sides and that is not quite the +2-3deg I was looking for.  By the way, are you running with the adjustable heim joints?  How do they work for street driving?

[signet]

can you get the original alignment sheet out for a scan then post it?

all the info on that paperwork can usually help determine what the problem is.

[Tywebb2]

I don't have a scanner but here is the info I was given:

                  camber       caster
   Left           0.3            -2.1

   Right         0.1             0.8

The toe is listed as 0.2 and 0.2? 

[Bill_Reilly]

On a system I tested here, I was able to get 2* extra from using the offset bushings, so it's not certain if the offset bushings would give you enough - really, you need something to give you an extra 5* on the left side. That's quite a bit. It's possible that the offset bushings and the shorter strut rod together might get you close. It's best to have 3* + caster, but if you can manage 1* on both sides you'll be fine.  You could machine the strut rods, but that causes binding in the lower bushing and pulls on the torsion bar, so I'm not a fan of doing that.  The trimmed bushing and offset arm bushings would be the best bet to do it cheap, if it works. The simplest method would be to use the adjustable strut rods and a-arms, which also fixes alot of other problems, although more expensive. You can eyeball caster easily with a little angle finder - cut yourself a short straightedge that's just long enough to reach between the upper and lower balljoint studs. Put the angle finder directly on that straight edge and you'll have a very accurate idea of how far the spindle leans back. If you look carefully, you'll be able to see within 1/2 degree, which isn't perfect, but plenty good enough to bypass the alignment shop on a street car. It's not so important that you know the caster to the 0.001 degree, but that both sides are close to equal - the eyeball angle finder method is definitely accurate enough to do that. Whether you have 2 degrees on both sides, or 2.5 degrees on both sides, the car will still behave well.
Keep in mind, you have to check the caster with the car sitting at it's ride height - if the nose is higher, or the wheels are not at the ride height position, the caster numbers will be all wrong - camber and caster are measured as the spindle angle in relation to the ground, so if the car or the suspension isn't at it's normal attitude, you'll get bad numbers. It's not easy to squiggle under the car to read the gauge, but it's a cheap, simple method. I've done it a million times here as the final alignment on my own car. I have customer cars aligned at a shop so I can give them true numbers, but it's far from necessary.

[Tywebb2]

Thanks for the feedback.  Do you think I could get away with just the adjustable UCA's without the adjustable strut rods?  Wouldn't tightening down the adjustable strut rods cause binding as well...i.e. to anything shorter than the 17.5" length I measured on my current set-up (inside front washer to LCA). 

[Bill_Reilly]

True and true. The adjustable uppers will take care of any alignment problems. And yes, tightening the strut rod will cause some binding in the lower arm. It's best to fix alignment with the uppers, and just use the strut rod to get rid of the sloppy bushing.

When I install the strut rods, I let the lower arm relax, and adjust the rod length to match up to it at that point - that way I know there is no binding in the lower. Then I put the uppers in and straighten out the alignment by adjusting those instead.

[Jim_Lusk]

Is the ride height correct? A lot of shops don't realize that this is the FIRST thing to adjust on a Chrysler product.

[moparrr07]

Is the ride height correct? A lot of shops don't realize that this is the FIRST thing to adjust on a Chrysler product.

on any vehicle

[Jim_Lusk]

Is the ride height correct? A lot of shops don't realize that this is the FIRST thing to adjust on a Chrysler product.

on any vehicle

Well, yes, but it's adjustable on the Chrysler products. I got in an argument at one shop over ride height. They don't even check it anymore.