Now that I have the power steering box and pump working as they should, I am back to the question of caster shims. As I stated in another thread, the alignment shop set the toe-in to specs and the camber was still within specs and the caster was at +2 1/2 degrees with no shims between the axle and springs. Having driven the truck a bit with the new steering box working, the truck still wanders a little bit although livable if I didn't make any changes. When coming out of a turn, the steering wheel does somewhat return to center but not entirely as compared to our new modern car. The 54-55 shop manual says the minimum caster should be 3 degrees and maximum should be 4 degrees. So right now it is only 1/2 degree below the minimum per the manual. If I want to correct the slight bit of wandering and make the truck a bit easier to drive, do I add a couple degrees of positive caster? Mid Fifty has 2 and 4 degree shims available and longer center bolts with larger heads. A 2 degree shim will put it at 1/2 degree above the maximum and the 4 degree will be 3 1/2 degrees above maximum. I have seen on the forum some guys use as much a 6 degree shims. Is 6 or 6 1/2 degrees getting too high, causing other problems? Will adding 2 degrees of positive caster to the 2 1/2 degrees I already have kill the wander and improve the return of the steering wheel when coming out of a turn? I am thinking adding 4 degrees would be too much. I am inclined to go with just adding the 2 degree shim. Is this a good plan or should I live with what I have now?
As always, your input is much appreciated.
Thanks---Bob

 

Bob,

Others with more ft. end knowledge then me are sure to reply. You are shimming between the axle and spring correct? That seems fairly easy to add or subtract. I would start with the 2 degree and see if it is the difference you seek. Then go up or down from there.

B

 

You want the 4 degree shims.
See my other posts on this subject.
Your truck specs were set for manual steering, very heavy loads, on bad roads, going slow, bias ply tires. I doubt you are going to use your truck in that way.
You do not want wander at high speed. All things equal, more degrees are needed to correct that.
The more degrees, the harder to turn the steering wheel. That is one reason factory spec is low on castor. No one wants to buy a truck that is very, very hard to turn steering wheel at low speeds. So a "happy medium" was struck between driveability and easier steering, But you have fixed the easier steering with the power steering. Hard steering not even an issue for your truck.
You do not want to be under spec, which is too low to start with. If jumping to 2 1/2 degrees over spec with 4 degree shims (total of 6 1/2 degrees for your truck based on what you said) seems scary, then go with 2 degrees. It will be better for sure, and maybe good enough for your style.
Others have other opinions that are different. Basically, its what works for you. Right now it sounds like it is not working to your liking. Try more degrees of castor.
If you have stock spring pack, be sure to buy the longer center bolt from Mid-fifty. You want the shim as part of the spring pack, held together with center bolt. Thick end toward back, thin end pointing toward the front.

 

I went back and re-read your response to my previous thread and I agree with your points there and here. I decided to get the 4 degree wedges and the new longer center bolt from Mid Fifty. The job to R&R the bolt and install the shims doesn't look too difficult as long as the springs are secured with a couple of clamps. I will let you know how it all works out in the coming days. Thanks for your reply's and information. I am looking forward to digging into this project, as ongoing as it always is. The fun never ends!