Vintage Mustang Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
519 Posts
Discussion Starter #1
I need to adjust my caster on my front end and was wondering if I move a shim from the back of the upper control arm to the front of the control arm, how many degrees of positive caster that equals?

I have about 2 to 3 degrees of negative caster now and want to end up with 1 to 2 degrees of positive. I thought maybe someone here would know approximately how many degrees each shim will give. Thanks.
 

·
Registered
Joined
·
6,911 Posts
When the 65/66 experts reply, I am curious....

I know 69/70 strut rods adjust caster....can you do the same on 65/66?
 

·
Registered
Joined
·
1,656 Posts
The 65/66 strut rods are non-adjustable and are merely torqued to specs. I would think that the thickness of the shim/shims would determine the caster change if they were simply moved from one side to the other. It seems to me that the caster and camber settings should be checked with allignment equipment when any shims are changed.
 
G

·
Guest
Joined
·
0 Posts
umm, measured in 1/16" i think to 1/2 degree, lemme check my book. nope, 1/32" is *approximately* 1/2 degree. I would think that the rate of change of the angle change with how offset they are to start with, so in other words, you cannot be sure and will need to get it checked out before hand.

Interestingly, the shop manual says shouldn't exceed 1/16" difference in stack . . not much recommended adjustment. Anyone else know how far you can go? I'm planning on dialing in some more castor myself at some point.
 

·
Registered
Joined
·
3,894 Posts
Yes, you can move one from the back to the front and increase caster. But, you should actually add one to the front and leave the one in the rear alone unless you want to increase negative camber too.

Most shims are 1/8" thick, I play with mine all the time. Remember, tha car will pull or steer AWAY from the side with more positive caster.

Another way to increase caster if shims can't get you there is to unbolt the upper control arm and rotate the bar (the one the two bolts pass through) such that the bolt holes move forward (ie: the upper ball joint will move rearward, more caster).
 

·
Registered
Joined
·
2,596 Posts
Hey Plessm: How've you been? We don't hear from you much these days. Is the car totally recovered from its dip in that canal? I hope so.

Anyhoo - regarding your question, the amount of positive caster added by removing a shim from the rear and moving it to the front will vary from car to car. You should know, though, that with Ford's wonderful alignment system on early cars, moving shims around will change the camber settings too.

Consider this: Re-bush or replace the upper arms with new stuff (unless they are pretty new already). Removing slop from the bushings and ball joints will do wonders for alignment accuracy.

While you've got the upper arms off the car, do the Shelby drop to the arm bolt locations. The 1/8 rearward set of the control arm mounts will help with the positive camber. The 1 inch downward movement will also make the car stick better in corners.

As far as how thick a wad of shims you can use on the front mounts goes, the manual says limit it to 1/16" - but both of my 66s had at least a quarter inch stack on both sides. No doubt to try and get a as much positive caster as possible.

IMHO, this (shimmed upper arms) is a miserable system and one that most alignment techs hate with a passion.

I hope that helps.
 

·
Registered
Joined
·
2,750 Posts
Shimming the strut rods will make the caster even more negative. Basically, you have to pull the rod in tighter to get more positive caster. It can't be done with the stock rods since they are fixed length. There are at least three aftermarket adjustable rods, TCP, Global West and Delta Bay Mustang. Of these, the lowest cost is Delta Bay. You can also make your own from '67 strut rods. To do this, you have to modify the flattened end as follows: mount the front hole of the '67 strut in the rear hole in the '65/'66 LCA temporarily. You'll note that the back of the flat extends past the LCA. You can cut this exta length off. Also note that the flat does not extend quite far enough forward so you'll have some machine work to flatten it. Carefully mark and drill the front hole in the modified strut rod to allow the front bolt in the LCA to be fitted. Once this is done, you'll have a strut rod of the right length to do the job. For hardware, use '67 Mustang parts for bushings, Chevy Nova parts work well. There will be some extra length up front so you'll want to trim it off and clean up the threads. The hard part is finding a set of '67 strut rods. They are quite hard to find these days.
 

·
Registered
Joined
·
519 Posts
Discussion Starter #8
Yeah, I've been out of the "Mustang hobby" for a few months. I was so disgusted with the amount of money and time I was having to spend to get my car back on the road again that I just put it down and didn't mess with it for awhile. I'm getting the bug and it's becoming enjoyable again.

I have been driving my car since March this year. Engine/trans/rear run strong. Interior is almost complete. Just working on the suspension now. My ball joints and leaf spring bushings are shot and I will be replacing those in the next month or so.

Thanks for the reply to my shim question and the inquiry about my car's status.
 
1 - 8 of 8 Posts
Top